| variation between strains of hamsters in the lethality of pichinde virus infections. | infection by pichinde virus, a member of the arenavirus group, was studied in golden syrian hamsters (mesocricetus auratus) with regard to possible mechanisms of resistance to virus infection in adult hamsters. two hamster strains were found to differ in their susceptibility to lethal pichinde virus infection. lvg/lak randomly bred hamsters were found to be 100% susceptible to low doses of pichinde virus during the first 6 days of life, but after 8 days of life, mortality was uncommon. peak viru ... | 1977 | 193786 |
| structural components of the arenavirus pichinde. | purified pichinde virions grown in monolayers of bhk-21 cells were found to contain three major species of virion proteins as described previously (ramos et al., j. virol. 10:661-667, 1972). two of the proteins were glycosylated (g1, molecular weight = 64,000; g2, molecular weight = 38,000) and were present in similar proportions on the outer surface of the virions. a third protein (n, molecular weight = 66,000) was not glycosylated and, in association with the viral rna species, was the major p ... | 1977 | 197271 |
| pseudotypes of vesicular stomatitis virus and pichinde virus. | super-infection of pichinde virus-infected cells with vesicular stomatitis virus (vsv) resulted in the production of pseudotype virus which was not neutralized by antiserum to vsv but which was neutralized by antiserum to pichinde virus. analysis of pseudotype virus production in relation to the kinetics of replication of pichinde virus demonstrated that pseudotype virus production occurred when super-infection with vsv was initiated 8 h or more after infecting the cells with pichinde virus. the ... | 1979 | 215705 |
| cytotoxic cells induced during lymphocytic choriomeningitis virus infection of mice. i. characterization of natural killer cell induction. | lymphocytic choriomeningitis virus (lcmv) infection of c3h/st, nude (balb/c background), and other mice induced high levels of natural killer (nk) cell activity in the spleen and peritoneum. l-929 cells were used as targetsand were not lysed by spleen or peritoneal cells from uninfected mice. the cytotoxic cells were characterized as nk cells because they were nonadherent, nonphagocytic lymphocytes lacking theta and immunoglobulin antigens on their plasma membranes. their activity was sensitive ... | 1978 | 307587 |
| the reticuloendothelium as the target in a virus infection. pichinde virus pathogenesis in two strains of hamsters. | the course of pichinde virus infection in two strains of hamsters, lvg and mha, was studied by sequential frozen-section immunofluorescence and light and electron microscopy. the major destructive effects of the infection were in the spleen and liver. in the spleen, primary target cells were macrophages in the marginal zone of the white pulp with subsequent spread into elements of the red pulp. in the liver, there was kupffer cell and hepatocellular infection. the extent of involvement correlate ... | 1977 | 335164 |
| differences between syrian hamster strains in natural killer cell activity induced by infection with pichinde virus. | | 1979 | 501084 |
| arenavirus defective interfering particles mask the cell-killing potential of standard virus. | lymphocytic choriomeningitis virus (lcm) and pichinde virus grew readily and produced cytopathology in mdck and pk-15 cells. it is known that in these cell lines, the synthesis or function of defective interfering (di) virus particles is restricted. survival curves of single mdck cells infected with low multiplicities of lcm showed one-particle-to-kill kinetics. at high multiplicities of infection, there was a maximum degree of cell-killing, or even a reduction in the amount of cell-killing, dep ... | 1978 | 627871 |
| arenavirus inactivation on contact with n-substituted isatin beta-thiosemicarbazones and certain cations. | n-methyl and n-ethyl isatin beta-thiosemicarbazones inactivate cell-free parana and pichinde viruses as well as three strains of lymphocytic choriomeningitis virus. this antiviral activity is abolished in the presence of the chelating agent edta. the rate of virus inactivation by n-methyl isatin beta-thiosemicarbazone is greatly enhanced and controlled by the addition of cupric sulphate. divalent cations of other first transition series metals are less effective. a difference exists in the coppe ... | 1975 | 809544 |
| inhibition of pichinde virus replication by actinomycin d. | the yields of pichinde virus, a member of the arenavirus group, were markedly inhibited when infected bhk 21 cells were incubated in the presence of 0.4 to 4 mug/ml of actinomycin d. maximal inhibition was observed when actinomycin d was added after the adsorption of virus to cultures; however, addition of drug as late as 12 h after infection reduced the 24 h yield by 50%. virus antigen synthesis, as measured by complement fixation and immunodiffusion, was not dramatically reduced by actinomycin ... | 1976 | 1003168 |
| requirement of cell nucleus for the replication of an arenavirus. | baby hamster kidney (bhk21) cells enucleated with cytochalasin b were infected with pichinde virus or sindbis virus. viral replication was measured by plaque assay, and the synthesis of viral antigens was determined by immunofluorescence. pichinde virus replication was completely inhibited in cells enucleated prior to infection as measured by both techniques while the replication of sindbis virus was unaffected. enucleation of cells at different times after infection with pichinde virus indicate ... | 1975 | 1235853 |
| possible involvement of endogenous beta-endorphin in the pathophysiological mechanisms of pichinde virus-infected guinea pigs. | previously, we demonstrated that naloxone, an opiate antagonist, prolonged survival of strain 13 guinea pigs infected with pichinde virus. thus, endogenous opiates may be involved in the pathogenesis of this viral disease. to determine whether endogenous opiate levels were affected by pichinde viral infection, beta-endorphin concentrations in plasma and cerebrospinal fluid (csf) of normal and infected strain 13 guinea pigs were measured by radioimmunoassay. cerebrospinal fluid beta-endorphin con ... | 1992 | 1319583 |
| increased platelet-activating factor (paf) concentrations in hearts and lungs of pichinde virus-infected guinea pigs. | platelet-activating factor (paf) has been implicated as a cause of cardiopulmonary disturbances in certain diseases. in the present study, concentrations of paf in hearts, lungs, whole blood, and other organs of control and pichinde virus-infected guinea pigs on post-inoculation days (pid) 10 and 14 were measured by radioimmunoassay. results were further confirmed by bioassay after separation and purification with thin-layer chromatography. paf concentration in the hearts and lungs of virus-infe ... | 1992 | 1334721 |
| metabolism of platelet-activating factor in neutrophils isolated from pichinde virus-infected guinea pigs. | metabolism of platelet-activating factor (paf) was studied in cultured polymorphonuclear neutrophils (pmns) obtained from pichinde virus-infected strain 13 guinea pigs. neutrophils obtained from control and infected guinea pigs on postinoculation days 10 and 14 were incubated with [3h]lyso-paf, [3h]paf, or [3h]acetate. after incubation for 1 h at 37 degrees c, formation of [3h]acyl-paf from either [3h]lyso-paf or [3h]paf increased significantly in pmns from infected guinea pigs compared to contr ... | 1992 | 1541904 |
| antiviral immunotoxins: antibody-mediated delivery of gelonin inhibits pichinde virus replication in vitro. | immunotoxins were produced and evaluated for antiviral activity against pichinde virus, a member of the family arenaviridae. immunoglobulins were conjugated to the ribosome-inactivating protein, gelonin, through a disulfide linkage to form the immunotoxins. immunotoxins were produced utilizing monoclonal antibodies, immunoglobulin-binding proteins and hyperimmune sera. an immunotoxin consisting of hyperimmune rabbit sera conjugated with gelonin displayed strong antiviral activity against pichind ... | 1991 | 1650165 |
| pulmonary responses of conscious strain 13 guinea pigs to pichinde viral infection. | a laboratory animal model for studying pulmonary responses to arenaviral infection was established with advanced technologies. tidal volume (tv), respiratory rate (rr), minute volume (mv), expiratory time (te), inspiratory time (ti), peak expiratory flow (pef), and specific pulmonary airway resistance (res) were measured with a double plethysmograph and a computer data-acquisition system in six conscious, strain 13 guinea pigs. using the same animal, experiments were conducted before and after s ... | 1991 | 1667202 |
| assessment of the specificity of cytotoxic t lymphocytes for the nucleoprotein of pichinde virus using recombinant vaccinia viruses. | pichinde virus (pv) infection of mice results in induction of a strong h-2 restricted, virus-specific cytotoxic t lymphocyte (ctl) response and rapid clearance of the virus. to define the specificities of ctl induced by pv infection, we constructed vaccinia virus recombinants containing cloned cdnas corresponding to full-length (vvnp) and a truncated form (vvnp 51-561) of the nucleoprotein (np) gene of pv. radioimmunoprecipitation analysis of infected cell lysates indicated that vvnp expressed a ... | 1990 | 1701987 |
| natural killer (nk) cell response to virus infections in mice with severe combined immunodeficiency. the stimulation of nk cells and the nk cell-dependent control of virus infections occur independently of t and b cell function. | the activation, proliferation, and antiviral properties of natural killer (nk) cells were examined in severe combined immunodeficiency (scid) mice to determine the influence of mature t or b cells on virus-induced nk cell functions and to more conclusively determine the antiviral properties of prototypical cd3- nk cells. nk cells were activated to high levels of cytotoxicity 3 d after infection of mice with lymphocytic choriomeningitis virus (lcmv) or murine cytomegalovirus (mcmv). analyses of s ... | 1991 | 1850779 |
| influence of volume expansion on capillary transport in the gut of pichindé virus infected strain 13 guinea pigs. | hydropenic strain 13 guinea pigs (gp13) injected with pichindé virus show marked jejunal capillary disruption determined by a reduction in protein reflection coefficient (sigma) [katz and starr, 1990]. these studies examined whether this is reversed by a 2% ringer's expansion, and whether anorexia may contribute to reduced sigma. gp13 were either infected or given a 60% expected ad lib diet, and were studied while under a 2% ringer's expansion. the results showed 1) infected gp13 separated into ... | 1991 | 1940885 |
| the effect of an arenavirus infection on liver morphology and function. | patients with severe lassa fever have high serum levels of liver enzymes. studies of the histology of the liver have shown only minor alterations, seemingly insufficient to account for death. pichinde virus is an arenavirus which causes severe illness similar to lassa fever in strain 13 guinea pigs, but does not cause severe illness in man. this can serve as a relatively safe model for studying the pathology and pathophysiology of fatal arenaviral infection. we used this infection to evaluate th ... | 1990 | 1974392 |
| characterization of pichinde virus infection of cells of the monocytic lineage. | to establish a model of viral infection of monocytes, we examined infection of human cells and cell lines of the monocytic series with the arenavirus pichinde virus. we demonstrate for the first time that human peripheral blood monocytes are susceptible to pichinde virus infection, as shown by immunoprecipatation of virus-specific polypeptides from infected cells, immunofluorescence analyses, and quantitation of virus production from infected cells. the human promyelocytic leukemia cell line hl6 ... | 1991 | 2041083 |
| pichinde virus infection in strain 13 guniea pigs reduces intestinal protein reflection coefficient with compensation. | pichinde virus inoculation into strain 13 guinea pigs is a model with features reputed to be similar to hemorrhagic fever in humans. although the infection is lethal by day 13-19, guinea pigs of approximately 600 g do not show edema or effusions. this raises the questions of whether capillary damage is present in such infected animals and, if it is, why edema is absent. the effects of pichinide virus on protein transport across jejunal capillaries were examined in 38 normal and 7 infected strain ... | 1990 | 2230259 |
| cytotoxic t lymphocytes do not control lymphocytic choriomeningitis virus infection of bb diabetes-prone rats. | biobreeding worcester diabetes-prone (bbdp) rats develop insulin-dependent autoimmune-driven diabetes mellitus spontaneously and intravenous administration of 1 x 10(7) p.f.u. of lymphocytic choriomeningitis virus (lcmv) to young adult mice prevents disease. the virus is lymphotropic, binding to and replicating in such cells. bbdp rats fail to generate virus-specific major histocompatibility complex-restricted cytotoxic t lymphocyte (ctl) responses when challenged with this dose or other doses o ... | 1990 | 2324708 |
| inhibition of diabetes in bb rats by virus infection. ii. effect of virus infection on the immune response to non-viral and viral antigens. | lymphocytic choriomeningitis virus (lcmv) infection prevents the usual insulin-dependent diabetes mellitus of aged bb rats (dyrberg, schwimmbeck & oldstone, 1988; schwimmbeck, dyrberg & oldstone, 1988). in this study earlier observations are extended by noting that lcmv infection substantially alters the immune responsesof bb diabetic-prone (dp) rats. the control, uninfected rats make vigorous primary and secondary antibody responses when challenged with keyhole limpet haemocyanin (klh), human i ... | 1990 | 2335372 |
| properties and characterization of monoclonal antibodies to tacaribe virus. | monoclonal antibodies prepared against tacaribe and junin viruses have been used to define further the serological relationships between arenaviruses of the tacaribe complex. a close relationship was found between these two viruses and the heterologous amapari and machupo viruses, with pichinde virus and parana virus being more distantly related. among the antibodies specific for tacaribe virus, five were found to react with viral antigens at the surface of infected cells and to neutralize virus ... | 1985 | 2410550 |
| virus-induced polyclonal cytotoxic t lymphocyte stimulation. | infections with a variety of viruses (lymphocytic choriomeningitis (lcmv), murine cytomegalovirus, pichinde virus, vaccinia virus) stimulated c57bl/6 mice to generate allospecific ctl coincidental with the generation of virus-specific ctl. in c57bl/6 (h-2b) mice, lcmv-induced ctl with reactivity against cells from mice bearing gene products of the d, f, k, p, q, and s but not the b mhc loci. studies with congenic mouse strains indicated that the mhc loci coded for the target of the allospecific ... | 1989 | 2537363 |
| arenavirus infection in the guinea pig model: antiviral therapy with recombinant interferon-alpha, the immunomodulator cl246,738 and ribavirin. | human arenaviral infections have a high mortality, and are dangerous to work with in the laboratory. there is a need for good antiviral agents to treat these infections. pichinde virus infection of the inbred strain 13 guinea pig is a relatively safe, good animal model for human arenavirus infections. mortality is consistently 100% between days 12 and 25 (mean 14.8) days after infection. when infected animals were treated with recombinant human interferon alpha a, or with cl246,783, an immunomod ... | 1989 | 2561334 |
| replication of hemorrhagic fever viruses in monocytic cells. | monocytes play a central role in protection against many viruses. in some infections they are target cells for viral replication. there is increasing evidence that these cells may also be important in regulation of hemostasis. the part played by monocytic cells in the pathogenesis of hemorrhage in the viral hemorrhagic fevers is presently uncertain. monocytes and monocytic cell lines have been used to investigate the ability of viruses to infect these cells in vitro. several factors may affect t ... | 1989 | 2665010 |
| pathogenesis of viral hemorrhagic fevers: rift valley fever and lassa fever contrasted. | although many viral infections have on occasion been associated with hemorrhagic complications, infection with any of several rna viruses regularly results in vascular involvement and the syndrome called viral hemorrhagic fever (vhf). in spite of clinically useful similarities among various vhfs, there are significant differences in their pathogenesis and clinical evolution; these are often related to characteristics of their viral taxon. infection with rift valley fever (rvf) virus, a phlebovir ... | 1989 | 2665011 |
| observation of the in situ contracting heart of guinea pigs infected with pichinde virus. | the in situ beating hearts from anesthetized control and pichinde virus-infected strain 13 guinea pigs, between days 7 and 19 postinoculation, were directly observed and video recorded. although some hearts from pichinde virus-infected animals were visually depressed and had altered contraction patterns, such a pronounced cardiac dysfunction was not associated with any marked histopathological changes in the cardiac tissue. the manifestations of cardiac dysfunction were limited mainly to the rig ... | 1987 | 2824949 |
| neurochemical changes in brains of mice infected with pichinde virus. | | 1986 | 2873503 |
| changes in body weight and body surface area in strain 13 guinea pigs infected with pichinde virus. | in studying pathogenetic mechanisms of pichinde virus-induced disease in strain 13 guinea pigs, a large decrease of body weight (approximately 28%) observed within 14 days postinoculation raises a question concerning the validity of standardizing body or organ functions in terms of body weight. this study was to examine changes in body weight and body surface area of pichinde virus-infected strain 13 guinea pigs after various days postinoculation. control guinea pigs were also subjected to the s ... | 1989 | 2915597 |
| abrogation of anti-pichinde virus cytotoxic t cell memory by cyclophosphamide and restoration by coinfection or interleukin 2. | previously, we demonstrated that memory cell-mediated immune responses can be generated in pichinde virus (pv)-primed mice after secondary challenge in vivo with homologous virus. further, treatment of mice with cyclophosphamide (cy) before primary infection with pv abrogated the generation of h-2-restricted, virus-specific cytotoxic t lymphocytes (ctl), and rechallenge of these mice was followed by neither a primary nor a secondary ctl response. here, we demonstrate that this cy-induced block i ... | 1985 | 2989365 |
| intraepithelial leukocytes contain a unique subpopulation of nk-like cytotoxic cells active in the defense of gut epithelium to enteric murine coronavirus. | initially the intraepithelial leukocytes (iel) of specific pathogen free (spf) mice were compared with those of mice held without isolation and were found to differ markedly in total number and distribution of cell surface antigens. the iel from spf mice expressed significantly less thy-1, lyt-1, and lyt-2 antigens than their conventional counterparts. the local cell-mediated immune response of mucosal lymphocytes to an enteric murine coronavirus (mhv-y) was studied in inbred strains of naive sp ... | 1986 | 3005395 |
| antibody to mouse alpha/beta interferon abrogates pichinde virus-induced liver lesions in suckling mice. | infection of newborn c3heb/fej mice with the arenavirus pichinde resulted in stunted growth, severe liver cell degeneration, and death. administration of sheep anti-mouse alpha/beta interferon globulin completely abrogated liver lesions in virus-infected mice, although it did not decrease the incidence of mortality. these results indicate that endogenous interferon may be responsible for some manifestations of viral disease. | 1986 | 3016334 |
| evidence for the involvement of sulfidopeptide leukotrienes in the pathogenesis of pichinde virus infection in strain 13 guinea pigs. | strain 13 guinea pigs inoculated subcutaneously with pichinde virus developed fever, lost body weight, decreased water and food consumption, and died at 14 +/- 0.6 days. after fpl-55712, a leukotriene d4 antagonist, was administered beginning on pid (post-inoculation day) 3 for 18 days, the magnitude of body weight loss decreased and food intake increased, despite a persistent fever. the treated guinea pigs also survived significantly longer than infected animals receiving placebo injection (21 ... | 1986 | 3025893 |
| accumulation and chemotaxis of natural killer/large granular lymphocytes at sites of virus replication. | a model for monitoring the accumulation of natural killer cell/large granular lymphocytes (nk/lgl) at a site of virus replication was studied by using mice infected i.p. with either lymphocytic choriomeningitis virus (lcmv), murine cytomegalovirus (mcmv), mouse hepatitis virus (mhv), pichinde virus, or vaccinia virus. an i.p. but not i.v. infection resulted in a localized increase in nk/lgl cell number (a fourfold to greater than 20-fold increase) and augmentation (a 10- to 20-fold increase) of ... | 1987 | 3027167 |
| studies of the coagulation system in arenaviral hemorrhagic fever: experimental infection of strain 13 guinea pigs with pichinde virus. | significant coagulation abnormalities were associated with experimental infection of strain 13 guinea pigs with pichinde virus, an arenavirus related to the virulent human pathogens junin, machupo, and lassa viruses. infected animals developed decreased activity of multiple coagulation factors, decreased antithrombin iii levels, high levels of fibrin-fibrinogen degradation products, impaired platelet function, and thrombocytopenia. testing for the presence of a coagulation inhibitor revealed a p ... | 1987 | 3030150 |
| [isolation and characteristics of monoclonal antibodies to the pichinde arenavirus]. | | 1988 | 3051668 |
| a newly developed immunofluorescent assay for determining the pichinde virus-inhibitory effects of selected nucleoside analogues. | an immunofluorescent assay (ifa) for pichinde virus (pcv), a member of the family arenaviridae, was developed for antiviral drug assays against the virus. the assay was performed by adding fluorescein-labeled anti-pcv monoclonal antibody to virus-infected cells at 24 h after the initial infection and counting the infected cells with an epifluorescence microscope. the average 50% effective dose (ed50) for a series of nucleoside analogues tested against pcv using this ifa was: 2-beta-d-ribofuranos ... | 1988 | 3069048 |
| immune serum increases arenavirus replication in monocytes. | the u937 monocytic cell line was used to determine whether antibodies could facilitate infection and replication of the arenaviruses, pichinde virus (pv) and lassa fever virus (lfv). when high dilutions of pv-immune serum were added to cultures simultaneously with pv inoculum, virus replication was dramatically (1000-fold) increased. low dilutions of this antiserum neutralized the virus. lfv also replicated in u937 cells. the presence of lfv-specific immune serum in the growth medium increased t ... | 1988 | 3292697 |
| localization of an arenavirus protein in the nuclei of infected cells. | host cell nuclear involvement in an arenavirus infection was examined by immunofluorescence. both polyclonal antisera and monoclonal antibodies specific for the major nucleocapsid (n) polypeptide revealed virus-specific nuclear inclusions in pichinde virus-infected vero cells. immunoprecipitation of infected cell extracts with the anti-n monoclonal antibodies and subsequent analysis by sds-page, identified two n-related proteins with mol. wt. of 36,000 (p36) and 28,000 (p28) in addition to the n ... | 1987 | 3309183 |
| biobreeding/worcester (bb/wor) rats are deficient in the generation of functional cytotoxic t cells. | the biobreeding/worcester (bb/wor) rat provides a good model of spontaneous autoimmune diabetes. there are several sublines of the bb/wor rat. the diabetes prone (dp) sublines develop diabetes at a frequency of 50 to 80% from 60 to 120 days of age. the dp rats are lymphopenic, have a severe deficit in phenotypic ox 19+ ox 8+ cytotoxic t cells (tc), and lack rt 6.1 t cells. these rats have a relative increase in ox 19- ox 8+ natural killer (nk) cells and in nk activity as compared with the diabet ... | 1987 | 3497974 |
| exquisite specificity of adoptive immunization in arenavirus-infected mice. | lymphocytic choriomeningitis virus (lcmv)-infected mice can be adoptively immunized with t cells from immune mice sharing mhc compatibility in h-2k or d, suggesting direct cytotoxic effects of t cells in vivo. however, t cells, upon recognition of an appropriate target, secrete lymphokines which may be capable of mediating antiviral effects nonspecifically. in this report we show that lcmv-immune cells reduced lcmv spleen titers in mice infected with lcmv alone or with lcmv and pichinde virus (p ... | 1985 | 3877492 |
| conserved sequences and coding of two strains of lymphocytic choriomeningitis virus (we and arm) and pichinde arenavirus. | analyses of the 3' end sequences of the small, s, and large, l, rna species of lymphocytic choriomeningitis (lcm) virus isolates arm and we, and dna clones of lcm-we, have shown that there are extensive rna sequence homologies between the 3' ends of the two rna species of both lcm strains. limited sequence data of dna clones representing the lcm-we l rna species indicate that a gene product (presumably the minor 200 kdalton virion protein) is coded in a viral-complementary mrna species. sequence ... | 1985 | 3984491 |
| thermal inactivation of pichinde virus. | detailed information regarding the kinetics of thermal inactivation of pichinde, an arenavirus, is presented. inactivation of virus infectivity proceeded as a first order reaction over the temperature range 22-53 degrees c. the determined inactivation rates analysed as a function of absolute temperature revealed that two different reactions were involved. below 37 degrees c, the energy of activation was determined to be compatible with rna degradation, whereas at higher temperatures a correspond ... | 1985 | 4030997 |
| complete sequence of the s rna of lymphocytic choriomeningitis virus (we strain) compared to that of pichinde arenavirus. | previous studies have reported that the 3' half of the small, s, rna species of the we strain of lymphocytic choriomeningitis (lcm) virus codes for the viral nucleoprotein in a subgenomic, viral-complementary, mrna species (romanowski, v. and bishop, d.h.l. (1985) virus res. 2, 35-51). the complete sequence of the lcm-we s rna has now been obtained, indicating that the 5' half of the rna codes for the viral glycoprotein precursor in a viral-sense sequence that does not overlap the n gene. it is ... | 1985 | 4060885 |
| polymerase activity of pichinde virus. | pichinde virus, a member of the arenavirus group, was examined for polymerase activity. purified virus was found to contain rna-dependent rna polymerase but not rna-dependent dna polymerase activity. since rnase but neither dnase nor actinomycin d inhibited the endogenous polymerase reaction, rna of the virus appeared to be used as the template. the divalent cations mg(2+) and mn(2+) were required for optimal reactivity. the rna product was partially resistant to rnase and the resistant portion ... | 1974 | 4132669 |
| effects of actinomycin d and ultraviolet and ionizing radiation on pichinde virus. | actinomycin d (0.05 mug/ml) suppresses the synthesis of ribosomal rna of baby hamster kidney (bhk21) cells. the production of infectious pichinde virus was enhanced in the presence of actinomycin d, although the production of virus particles was not substantially different from cultures inoculated in the absence of the drug. by prelabeling bhk21 cells with (3)h-uridine and then allowing the virus to replicate in the presence of actinomycin d, it was possible to show that ribosomal rna synthesize ... | 1973 | 4199107 |
| characterization studies of the pichinde virus-a member of the arenavirus group. | | 1971 | 5544511 |
| pichinde virus-specific cell-associated suppression of primary footpad swelling in an inbred strain of syrian hamsters. | pichinde virus causes a lethal disease after i.p. inoculation of adult mha hamsters; other strains of syrian hamsters are resistant to this lethal infection. during studies of cell-mediated immune responses to pichinde virus, it was noted that mha hamsters survived infection when the virus was given in the footpad. however, unlike the resistant lsh and lvg strains of hamsters, the mha hamsters did not manifest a footpad swelling response. failure of the mha hamster to respond to a footpad inocul ... | 1983 | 6184408 |
| immune recognition of tumor cells in mice infected with pichinde virus. | pichinde virus (pv), a member of the arenaviridae family, protects mice from a lethal inoculation with the sarcoma 180 (s180) tumor cell line. virus replication, which is required for protection, occurs primarily in the spleen and tumor. during the first 4 days, elevated natural killer (nk) cell activity parallels an increase in serum interferon in pv-infected mice. on day 7 after infection virus-specific cytotoxic t cells (ctls) are found in the mouse. this strong response peaks on day 13 and g ... | 1984 | 6203637 |
| susceptibility to fatal pichinde virus infection in the syrian hamster. | the data presented in this paper suggest that the susceptible mha hamster strain possesses a spleen target cell for pichinde virus replication which is minimally expressed in the resistant strain. this target cell co-purifies with cells mediating nk activity, raising the possibility that the nk cell itself may be the additional target cell for pichinde virus replication in the susceptible hamster strain. we hypothesize that early virus replication in the spleens of ip-inoculated hamsters leads t ... | 1981 | 6261541 |
| role of natural killer cells in pichinde virus infection of syrian hamsters. | pichinde virus produced a fatal infection in adult mha hamsters but not lsh hamsters after intraperitoneal inoculation. after footpad inoculation, an 8-day swelling response was observed in lsh but not mha hamsters; however, both strains survived infection by this route. examination of the kinetics of viral replication in the two hamster strains inoculated by the two routes revealed a correlation between infectious centers and natural killer activity in cells obtained from spleens and popliteal ... | 1981 | 6262252 |
| pathogenesis of a pichinde virus strain adapted to produce lethal infections in guinea pigs. | a model for studying the pathogenesis of virulent arenavirus infection was developed by adapting pichinde virus to produce lethal infections of inbred guinea pigs. this adapted pichinde virus retained low virulence for primates, thus potentially reducing the biohazard to investigators. whereas all inbred (strain 13) guinea pigs were infected and killed by 3 plaque-forming units or more of adapted pichinde virus injected subcutaneously, outbred (hartley strain) guinea pigs were relatively resista ... | 1981 | 6265367 |
| analyses of the genomes of prototype pichinde arenavirus and a virulent derivative of pichinde munchique: evidence for sequence conservation at the 3' termini of their viral rna species. | | 1982 | 6278715 |
| antiviral efficacy of pyrazofurin against selected rna viruses. | the antibiotic pyrazofurin, 3-(beta-d-ribofuranosyl)-4-hydroxypyrazole-5-carboxamide, markedly inhibited the in vitro replication of a number of rna viruses including rift valley fever (rvf), venezuelan equine encephalomyelitis (vee), sandfly, pichinde, lassa and lcm virus. plaque formation was reduced by 80% or more with 2-10 micrograms/ml of pyrazofurin while 2 micrograms/ml reduced by 1000-fold the yield of lassa and lcm virus in a yield reduction assay. in vivo, pyrazofurin failed to protect ... | 1982 | 6299188 |
| [sedimentation analysis of the virion rna of machupo virus]. | pichinde and machupo viruses labeled with 3h-uridine were concentrated and purified by different methods. the buoyant density of the viruses was for pichinde 1.14-1.15 g/cm3 (urographimeter), 1.19 g/cm3 (sucrose), 1.25 g/cm3 (cesium chloride), for machupo virus 1.25 g/cm3 (cesium chloride). virion rnas of pichinde and machupo viruses were divided in sucrose concentration gradient into 4 sedimentation classes: 7-10 s, 18 s, 20-22 s, and 28-30 s. virion 28 s and 18 s rnas cosedimented with ribosom ... | 1983 | 6314674 |
| generation of memory cell-mediated immune responses after secondary infection of mice with pichinde virus. | pichinde virus (pv), a member of the arenavirus group, was found to elicit strong cell-mediated immune responses in various strains of mice. after primary i.v. inoculation, augmentation of natural killer (nk) cell activity occurred and peaked 3 to 4 days after infection. the nk response was followed by a second peak of cytotoxic activity that was found to be h-2 restricted, virus specific, and mediated by thy-1.2+, lyt-2.2+ lymphocytes. this cytotoxic t lymphocyte (ctl) response peaked 7 days po ... | 1984 | 6317748 |
| ribonucleic acids of machupo and lassa viruses. | sucrose gradient velocity centrifugation, polyacrylamide gel electrophoresis and rna-rna hybridization were used to characterize lassa and machupo virion rnas as well as virus-specific rnas from cells infected with pichinde and machupo viruses. five rna species: 30-31s, 28s, 22-24s, 18s and 4-6s have been detected in lassa, machupo, and pichinde virion rnas. among them 28s, 18s and 4-6s rnas cosediment and comigrate with respectively cell rnas. rnase resistance analyses suggest the presence of e ... | 1984 | 6320777 |
| the sequences of the n protein gene and intergenic region of the s rna of pichinde arenavirus. | two overlapping dna clones representing more than half of the pichinde arenavirus s rna segment were cloned into pbr322 and their nucleotide sequences were determined. the analyses predict that the viral nucleocapsid protein (n) is encoded in a reading frame in the viral complementary rna sequence starting at viral s rna nucleotide residue 84 from the 3' end and terminating with an opal codon at residues 1767-1769. the position of the termination codon has been confirmed by primer directed dideo ... | 1984 | 6324469 |
| sequencing studies of pichinde arenavirus s rna indicate a novel coding strategy, an ambisense viral s rna. | analyses of the complete sequence of the 1.1 x 10(6)-dalton, small (s) rna of the arenavirus pichinde and virus-induced cellular rna species have revealed that the viral nucleoprotein, n, is coded in a subgenomic, non-polyadenylated, virus-complementary mrna corresponding to the 3' half of the viral rna (auperin et al., virology 134:208-219, 1984). by contrast, a second s-coded product, presumably the viral glycoprotein precursor (gpc), is coded in a subgenomic, virus-sense mrna corresponding to ... | 1984 | 6492264 |
| differences in lymphocyte responsiveness to lymphokines in two inbred strains of syrian hamster. | two inbred strains of syrian hamster have been shown to display differences in splenic nk cell activity both endogenously and after infection with pichinde virus. on further investigation of these differences, it was found that the spleens and thymuses of the high nk strain, mha, displayed greater cellularity than those of the low nk strain, lsh. additionally, thymocytes from mha hamsters were found to proliferate to a greater extent than those of lsh hamsters in response to con a-induced condit ... | 1984 | 6609982 |
| broad-spectrum antiviral activity of 2-beta-d-ribofuranosylselenazole-4-carboxamide, a new antiviral agent. | the relative in vitro antiviral activities of three related nucleoside carboxamides, ribavirin (1-beta-d-ribofuranosyl-1,2,4-triazole-3-carboxamide), tiazofurin (2-beta-d-ribofuranosylthiazole-4-carboxamide), and selenazole (2-beta-d-ribofuranosylselenazole-4-carboxamide), were studied against selected dna and rna viruses. although the activity of selenazole against different viruses varied, it was significantly more potent than ribavirin and tiazofurin against all tested representatives of the ... | 1983 | 6615611 |
| fine structure analysis of pichinde virus nucleocapsids. | the structure and organization of the ribonucleoprotein (rnp) complex of an arenavirus, pichinde virus, was investigated. the basic configuration of the rnp was found to be a linear array of globular subunits or nucleosomes, 4 to 5 nm in diameter, that represent individual molecules of the major n polypeptide. this filament appears to fold progressively through a number of intermediate helical structures, 12 to 15 nm in diameter, that reveal an increasing number of nucleosomes associated with ea ... | 1983 | 6682139 |
| endo-beta-n-acetylglucosaminidase f: endoglycosidase from flavobacterium meningosepticum that cleaves both high-mannose and complex glycoproteins. | we have detected an endoglycosidase activity produced by flavobacterium meningosepticum. this enzyme, named endo f, cleaves glycans of both the high-mannose and the complex type linked through asparagine to the protein backbone. the data indicate that cleavage occurs via hydrolysis of the glycosidic bond of the n,n'-diacetylchitobiose core structure adjacent to asparagine, similar to that due to endo h and endo d. extreme variability was noted in the availability of this cleavage site among n-li ... | 1982 | 6812050 |
| differential alterations in host peripheral polymorphonuclear leukocyte chemiluminescence during the course of bacterial and viral infections. | previous studies have shown that stimulation of the oxidative metabolism in polymorphonuclear leukocytes (pmn) by in vitro phagocytosis of various microorganisms results in photon emission, termed chemiluminescence (cl). studies were conducted to determine whether bacterial and viral infections induce enhanced basal endogenous host peripheral pmn cl in the absence of in vitro phagocytic stimulation. nonimmune rats and guinea pigs as well as immune rats were inoculated with various doses (10(5) t ... | 1980 | 7228389 |
| [accumulation of certain arenaviruses in transplantable vero and bhk-21 cells]. | production of lassa and machupo viruses in vero and bhk-21 cells was studied in relation to various conditions of the infected cell cultivation and as a function of different multiplicities of infection. the highest titers (expressed in pfu/ml) were obtained when the cells were grown in roller bottles with daily changes of the medium. the maximum titer in lassa virus-infected cells was over 10(6), in machupo virus-infected cells over 10(7). the effect of the autointerfering factor on the growth ... | 1981 | 7269524 |
| changes in cell adhesion molecule expression on t cells associated with systemic virus infection. | virus-induced changes in adhesion molecule expression on t cells were investigated to understand how antiviral effector cells migrate into infectious foci. facs analysis revealed that after systemic infection with lymphocytic choriomeningitis virus a number of cell adhesion molecules, including vla-4, lfa-1, and icam-1, are up-regulated on cd8+ cells, whereas the lymph node homing receptor mel-14 is down-regulated during the infection; only marginal changes were observed for cd4+ cells. basicall ... | 1994 | 7507962 |
| analysis of pichinde arenavirus transcription and replication in human thp-1 monocytic cells. | human promonocytic thp-1 cells were previously shown to be nonpermissive for pichinde virus (pv) replication unless the cells were induced to differentiate to macrophages by stimulation with phorbol ester (pma) (j. virol. 65, 3575, 1991). the restriction did not involve receptor modulation, virus binding, nor internalization of virus but a requirement for a host cell function in pv replication was observed in that the phorbol ester effect required protein kinase c activation and was inhibited by ... | 1995 | 7625125 |
| tumor necrosis factor and the pathogenesis of pichinde virus infection in guinea pigs. | pichinde virus (pic) is a reticuloendothelial arenavirus of the new world tropics. a guinea pig passage-adapted strain of this virus (adpic) is uniformly lethal for inbred guinea pigs, while the related, prototype strain (pic3739) has attenuated virulence. the abilities of adpic and pic3739 to induce tumor necrosis factor (tnf) in vivo and in cultured macrophages were compared. infection with adpic, but not pic3739, was associated with detectable serum tnf that peaked in week 2 of infection. tum ... | 1995 | 7694969 |
| 5' termini of pichinde arenavirus s rnas and mrnas contain nontemplated nucleotides. | primer extension of pichinde arenavirus purified virion rna suggests that genomes have at least a single nontemplated base at the 5' end which is a g in all cdna clones having one such single base. on the other hand, the predominant products of primer extension on total virus-infected-cell rna are at positions -1 and -2. the primer extension product at position -2 is not represented in virion rna, and neither of these products is proportionally represented in mrna. mrna is predominantly 3 or 4 b ... | 1995 | 7707553 |
| the nucleoprotein of pichinde virus expressed by a vaccinia-pichinde virus recombinant partially protects hamsters from lethal virus challenge. | syrian hamsters, strain mha/lak, are susceptible to intraperitoneal infection with pichinde virus and die from an overwhelming viremia. we have studied the ability of a vaccinia-pichinde recombinant virus expressing amino acids 51-561 of the viral nucleoprotein (vvnp51-561) to protect from lethal pichinde virus infection. priming with vvnp51-561 significantly delayed mortality and increased final survival outcome after challenge with 2 x 10(3) pfu of pichinde virus. this protection was not compl ... | 1994 | 7826212 |
| cardiovascular and pulmonary responses to pichinde virus infection in strain 13 guinea pigs. | in fatal human lassa fever, severe hypotension, circulatory shock, and pulmonary edema develop as terminal events. we examined cardiovascular and respiratory functions in strain 13 guinea pigs infected with pichinde virus, an animal model for studying human lassa fever. cardiovascular functions were studied in anesthetized and conscious guinea pigs, whereas pulmonary functions were measured only on animals under anesthesia. in anesthetized animals, cardiovascular disturbances were severe and pro ... | 1994 | 7898034 |
| pathological and virological features of arenavirus disease in guinea pigs. comparison of two pichinde virus strains. | a guinea pig passage-adapted strain of the arena-virus pichinde (adpic) is highly virulent in inbred guinea pigs, whereas the related strain pic3739 is attenuated. both viruses were macrophage tropic and infected peritoneal, splenic, liver, and alveolar macrophages during experimental pichinde virus infection. infection with the virulent strain was associated with unlimited viral replication in the face of exaggerated delayed-type hypersensitivity response, manifested by the macrophage disappear ... | 1994 | 8030751 |
| changes in platelet-activating factor, catecholamine, and serotonin concentrations in brain, cerebrospinal fluid, and plasma of pichinde virus-infected guinea pigs. | brain concentrations of platelet-activating factor (paf), catecholamines, and serotonin were measured in control and pichinde virus-infected strain 13 guinea pigs on postinoculation day (pid) 12. after virus inoculation, paf concentrations increased 81% in cerebrum, 147% in diencephalon-brain stem, and 110% in cerebellum from baseline values of 2.6 +/- 0.3, 4.3 +/- 0.2, and 6.1 +/- 0.5 (ng/g wet tissue), respectively. dopamine concentrations in the infected cerebrum and diencephalon-brain stem i ... | 1993 | 8158981 |
| cross-reactivities in memory cytotoxic t lymphocyte recognition of heterologous viruses. | analyses of the relationships between different viruses and viral proteins have focused on homologies between linear amino acid sequences, but cross-reactivities at the level of t cell recognition may not be dependent on a conserved linear sequence of several amino acids. the ctl response to pichinde virus (pv) and vaccinia virus (vv) in c57bl/6 mice previously immunized with lymphocytic choriomeningitis virus (lcmv) included the reactivation of memory cytotoxic t lymphocyte (ctl) specific to lc ... | 1994 | 8195718 |
| pichinde virus-induced respiratory failure due to obstruction of the small airways: structure and function. | respiratory distress that leads to death is seen in patients with lassa fever. the development of this respiratory problem was studied using a pichinde virus model (10(4) plaque forming units, ip, survival time 20 +/- 1 days) in strain 13 guinea pigs (n = 35, 229-353 g) of this lethal human contagious infectious disease. extravascular lung water to bloodless dry lung weight (evlw/bdlw) ratio showed a modest yet significant increase in animals 13 and 18-21 days postinoculation (pi). in contrast, ... | 1993 | 8281916 |
| treatment of lethal pichinde virus infections in weanling lvg/lak hamsters with ribavirin, ribamidine, selenazofurin, and ampligen. | a lethal pichinde (an 4763 strain) virus infection was produced in 3-week-old random-bred golden syrian (lvg/lak strain) hamsters inoculated intraperitoneally with virus, causing mortality in 6-9 days. high virus titers (> or = 10(7.5) cell culture infectious doses/g) were present in visceral organs, serum, brain and salivary glands near the time of death. intraperitoneal treatments with ribavirin (10 and 32 mg/kg) and ribamidine (32, 100, and 320 mg/kg) for 10 days starting 24 h after virus cha ... | 1993 | 8384433 |
| haemostatic derangements associated with arenavirus infection in the guinea-pig: radioimmunoassay of fibrinopeptide a to assess thrombin action in infected animals. | pichinde virus infection of inbred guinea-pigs is a model for arenaviral infections in humans. infected animals experience reduced levels of multiple coagulation factors caused by either consumption coagulopathy or impaired factor synthesis. a radioimmunoassay (ria) of guinea-pig fibrinopeptide a (gfpa) has been developed to measure the degree of thrombin action in vivo. gfpa was synthesized via the solid-phase method and conjugated to bovine serum albumin (bsa). a double antibody ria was establ ... | 1993 | 8384497 |
| death after pichinde virus infection in large and small strain 13 guinea pigs. | the lethal events of pichinide virus infections were studied in large (> 36-week-old), small (4- to 6-week-old), and uninfected strain 13 guinea pigs. time to death was shorter and the rate of body weight loss greater for large than for small virus-infected guinea pigs. severely ill large guinea pigs developed a life-threatening, nonlactate metabolic acidemia with an increased anion gap, hypokalemia, and renal failure. small infected guinea pigs near death demonstrated a modest increase in blood ... | 1993 | 8387562 |
| pathogenesis of pichinde virus infection in strain 13 guinea pigs: an immunocytochemical, virologic, and clinical chemistry study. | pichinde virus has been adapted to produce lethal infection of strain 13 guinea pigs. viral replication and presence of viral antigen in frozen tissues stained by immunofluorescence has been previously described. further investigation into the pathogenesis of this disease has been hampered by the lack of a light microscopic method for correlating histologic lesions and the presence of pichinde viral antigens. for this purpose, we developed a sensitive immunocytochemical technique for staining pi ... | 1993 | 8394659 |
| role of atrial natriuretic peptide in disturbed water and electrolyte metabolism of guinea pigs infected with pichinde virus. | daily intake and output of water and electrolytes (na+, k+, and cl-) were determined for 14 days in control and pichinde virus-infected strain-13 guinea pigs. although water intake began to decrease 7 days after virus inoculation, total daily water output (insensible water loss, urine excretion, plus fecal water loss) had little change. however, insensible water loss alone increased markedly in the virus-infected animals. both intake and excretions of urinary and fecal electrolytes decreased at ... | 1995 | 8569144 |
| persistent infection of mice with pichinde virus associated with failure to thrive. | intracranial inoculation of neonatal mice of certain inbred strains with pichinde virus has been found to be fatal, but balb/c neonates survive such infection. survival of balb/c mice after neonatal inoculation was not linked to the major histocompatability complex. virus was gradually cleared in surviving balb/c mice but could be detected in the brain and kidneys for up to 9 months after infection. these animals were not immunologically tolerant but exhibited high antibody titers to viral antig ... | 1995 | 8577237 |
| cd40l-deficient mice show deficits in antiviral immunity and have an impaired memory cd8+ ctl response. | the ligand for cd40 (cd40l) is expressed on the surface of activated cd4+ t cells and its role in t-b cell collaborations and thymus-dependent humoral immunity is well established. recently, by generating cd40l-knockout mice, we have confirmed its previously described role in humoral immunity and defined another important function of this molecule in the in vivo clonal expansion of antigen-specific cd4+ t cells. here, we investigated the potential in vivo role of cd40l in antiviral immunity by e ... | 1996 | 8642323 |
| reduction of otherwise remarkably stable virus-specific cytotoxic t lymphocyte memory by heterologous viral infections. | experimental analyses of the acute cytotoxic t lymphocyte (ctl) response to viruses have focused on studying these infections in immunologically naive hosts. in the natural environment, however, viral ctl responses occur in hosts that are already immune to other infectious agents. to address which factors contribute to the maintenance and waning of immunological memory, the following study examined the frequencies of virus-specific ctl precursor cells (pctl) not only using the usual experimental ... | 1996 | 8676069 |
| inhibition of arenavirus multiplication in vitro by phenotiazines. | trifluoperazine (tfp) and chlorpromazine (cpz), two pharmacologically active phenotiazine derivatives, were evaluated for their inhibitory activity on the replication of the arenaviruses junin (jv), the etiological agent of argentine hemorrhagic fever, tacaribe virus and pichinde virus. both compounds achieved a concentration-dependent inhibition of viral multiplication at concentrations not affecting cell viability. the 50% inhibitory concentration (ic50) values determined by a virus yield inhi ... | 1996 | 8811199 |
| the lassa fever virus l gene: nucleotide sequence, comparison, and precipitation of a predicted 250 kda protein with monospecific antiserum. | the large (l) rna segment of lassa fever virus (las) encodes a putative rna-dependent rna polymerase (rdrp or l protein). similar to other arenaviruses, the las l protein is encoded on the genome-complementary strand and is predicted to be 2218 amino acids in length (253 kda). it has an unusually large non-coding region adjacent to its translation start site. the las l protein contains six motifs of conserved amino acids that have been found among arenavirus l proteins and core rdrp of other seg ... | 1997 | 9049403 |
| sequence analysis of the small rna segment of guinea pig-passaged pichinde virus variants. | the established animal model for lassa fever is based on the new world arenavirus pichinde (pic). natural isolates of pic virus are attenuated in guinea pigs, but serial guinea pig passage renders them extremely virulent in that host. we have compared the nucleotide sequences of the small rna segments of two attenuated, low-passage variants of the pic virus munchique strain (coan 4763) and two virulent, high-passage derivatives. missense mutations in the glycoprotein precursor (gpc) gene at codo ... | 1999 | 10463670 |
| virus-induced abrogation of transplantation tolerance induced by donor-specific transfusion and anti-cd154 antibody. | treatment with a 2-week course of anti-cd154 antibody and a single transfusion of donor leukocytes (a donor-specific transfusion or dst) permits skin allografts to survive for >100 days in thymectomized mice. as clinical trials of this methodology in humans are contemplated, concern has been expressed that viral infection of graft recipients may disrupt tolerance to the allograft. we report that acute infection with lymphocytic choriomeningitis virus (lcmv) induced allograft rejection in mice tr ... | 2000 | 10666251 |
| antiviral and virucidal activities against arenaviruses of zinc-finger active compounds. | fifteen antiretroviral zn-finger active compounds with diverse chemical structures, including azoic compounds, hydrazide derivatives, disulphide-based reagents and others were screened in vitro against junin virus (junv), the aetiological agent of argentine haemorrhagic fever, by a virus yield inhibition assay in vero cells. cytotoxicity was evaluated simultaneously by the mtt method. of the compounds, three were totally inactive as antivirals, nine presented moderate anti junv-activity and thre ... | 2000 | 10901294 |
| nucleotide sequence of the pirital virus (family arenaviridae) small genomic segment. | pirital virus is a newly discovered south american member of the family arenaviridae. we determined that the complete nucleotide sequence of the small genomic segment of pirital virus is 3393 nt long, and encodes the viral nucleoprotein (n) and glycoprotein precursor (gpc) (561 aa and 509 aa, respectively) in nonoverlapping open reading frames of opposite polarities. the n and gpc genes are separated by an intergenic region that is 80 nt long; the predicted secondary structure of this region inc ... | 2001 | 11162687 |
| alterations in nf-kappab and rbp-jkappa by arenavirus infection of macrophages in vitro and in vivo. | pichinde virus is an arenavirus that infects guinea pigs and serves as an animal model for human lassa fever. an attenuated pichinde virus variant (p2) and a virulent variant (p18) are being used to delineate pathogenic mechanisms that culminate in shock. in guinea pigs, the infection has been shown to begin in peritoneal macrophages following intraperitoneal inoculation and then spreads to the spleen and other reticuloendothelial organs. we show here that infection of the murine monocytic cell ... | 2002 | 11773391 |
| reassortant analysis of guinea pig virulence of pichinde virus variants. | the new world arenavirus pichinde (pic) is the basis of an accepted small animal model for human lassa fever. pic (munchique strain) variant p2 is attenuated in guinea pigs, whereas variant p18 is extremely virulent. previous sequence analysis of the s segments of these two viruses indicated a small number of possible virulence markers in the glycoprotein precursor (gpc) and nucleoprotein (np) genes. in order to determine the role of these s segment genes in guinea pig virulence in this system, ... | 2001 | 11883003 |
| characterization of the glycoproteins of crimean-congo hemorrhagic fever virus. | crimean-congo hemorrhagic fever (cchf) virus is the cause of an important tick-borne disease of humans throughout regions of africa, europe, and asia. like other members of the genus nairovirus, family bunyaviridae, the cchf virus m genome rna segment encodes the virus glycoproteins. sequence analysis of the cchf virus (matin strain) m rna segment revealed one major open reading frame that potentially encodes a precursor polyprotein 1,689 amino acids (aa) in length. comparison of the deduced ami ... | 2002 | 12072526 |
| phylogeny of the venezuelan arenaviruses. | guanarito virus (the etiologic agent of venezuelan hemorrhagic fever, vhf) and pirital virus coexist in the region of venezuela in which venezuelan hemorrhagic fever is endemic. the purpose of this study was to extend our knowledge of the evolutionary relationship between these two arenaviruses. we determined that the large genomic segments of guanarito virus and pirital virus are similar in size and identical in structural organization to the large genomic segments of other south american arena ... | 2004 | 15084402 |
| private specificities of cd8 t cell responses control patterns of heterologous immunity. | cd8 t cell cross-reactivity between viruses can play roles in protective heterologous immunity and damaging immunopathology. this cross-reactivity is sometimes predictable, such as between lymphocytic choriomeningitis virus (lcmv) and pichinde virus, where cross-reactive epitopes share six out of eight amino acids. here, however, we demonstrate more subtle and less predictable cross-reactivity between lcmv and the unrelated vaccinia virus (vv). epitope-specific t cell receptor usage differed bet ... | 2005 | 15710651 |
| evaluating the immunogenicity and protective efficacy of a dna vaccine encoding lassa virus nucleoprotein. | several viruses in the arenavirus genus of the family arenaviridae cause severe, often fatal, hemorrhagic fever. one such virus, lassa virus (lv), is a frequent cause of disease in africa, and survivors often are left with substantial neurological impairment. the feasibility of protective immunization against lv infection, and the associated disease, has been demonstrated in animal models, using recombinant vaccinia viruses to deliver lassa proteins. circumstantial evidence implicates cellular i ... | 2005 | 15823608 |
| interferon alfacon-1 protects hamsters from lethal pichinde virus infection. | hemorrhagic fever of arenaviral origin is a frequently fatal infectious disease of considerable priority to the biodefense mission. historically, the treatment of arenaviral infections with alpha interferons has not yielded favorable results. here we present evidence that interferon alfacon-1, a nonnaturally occurring bioengineered alpha interferon approved for the treatment of chronic hepatitis c, is active against pichinde and tacaribe arenaviruses in cell culture. in the hamster model of pich ... | 2005 | 15917537 |
| narrowed tcr repertoire and viral escape as a consequence of heterologous immunity. | why some virus-specific cd8 tcr repertoires are diverse and others restricted or "oligoclonal" has been unknown. we show here that oligoclonality and extreme clonal dominance can be a consequence of t cell cross-reactivity. lymphocytic choriomeningitis virus (lcmv) and pichinde virus (pv) encode np(205-212) epitopes that induce different but highly cross-reactive diverse tcr repertoires. homologous viral challenge of immune mice only slightly skewed the repertoire and enriched for predictable tc ... | 2006 | 16614754 |
| differential signaling networks induced by mild and lethal hemorrhagic fever virus infections. | the family arenaviridae includes several national institutes of allergy and infections diseases category a select agents which cause hemorrhagic fever. there are few vaccines available, and treatment is limited to ribavirin, which varies in efficacy. development of new antiviral compounds has been hindered by a lack of understanding of the molecular basis of pathogenesis. we used two variants of pichinde virus, one attenuated and one virulent in the guinea pig model, to delineate the host determ ... | 2006 | 17005702 |