| feline leukaemia virus: generation of pathogenic and oncogenic variants. | | 1991 | 1667630 |
| evolutionary conservation and chromosomal localization of flvi-1. | a locus in feline dna, termed flvi-1, has been identified as harboring retroviral integrations commonly found in natural feline lymphomas induced by infection with feline leukemia virus (felv). southern blot analysis of human and murine dna using restriction fragments representing flvi-1 demonstrates its phylogenetic conservation among mammals, flvi-1 is localized to murine chromosome 2, proximal portion of band e, by in situ hybridization to metaphase chromosomes. this position is adjacent to t ... | 1991 | 1679530 |
| colloquium on feline leukemia virus/feline immunodeficiency virus: tests and vaccination. orlando, florida, march 1-3, 1991. | | 1991 | 1686876 |
| virus neutralizing and enhancing epitopes characterized by synthetic oligopeptides derived from the feline leukaemia virus glycoprotein sequence. | synthetic peptides that mimic antigenic determinants of viral proteins were used in vaccine studies of feline leukaemia virus (felv) infection. immunoreactive epitopes on felv gp70 and p15e were predicted according to the criteria of their terminal position, hydrophilicity and the probability of them constituting helical structures. nineteen peptides, consisting of seven to 19 amino acid residues, were synthesized, of which two peptides were derived from the felv subtype a, 16 from subtype b and ... | 1990 | 1689371 |
| biological effects of staphylococcal protein a immunotherapy in cats with induced feline leukemia virus infection. | biological effects of staphylococcal protein a (spa) immunotherapy were studied in 5 viremic and 6 nonviremic cats with induced felv infection and in 6 control cats. the spa therapy neither reversed felv viremia nor resulted in consistent improvement in humoral immune responses to felv antigens. however, spa immunotherapy induced a proliferative response in bone marrow granulocytic lineage, possibly resulting in expression of felv-free mature neutrophils in the blood. seemingly, viral burden and ... | 1990 | 1690524 |
| receptor interference groups of 20 retroviruses plating on human cells. | the types of receptors on the surfaces of human and other mammalian cells for 13 c-type and 7 d-type retrovirus strains were determined by interference to the formation of syncytia and the plating of viral pseudotypes. all the d-type simian retroviruses (srv-1-5, smrv, po-1-lu) share a common receptor which is also utilized by the baboon and cat endogenous c-type viruses (baev, rd114). syncytial cross-interference was also observed in human cells between the gibbon ape leukemia/simian sarcoma as ... | 1990 | 1691887 |
| presentation and immunogenicity of viral epitopes on the surface of hybrid hepatitis b virus core particles produced in bacteria. | we recently reported the enhanced immunogenicity of a peptide epitope when it was presented as a fusion protein with hepatitis b core antigen. in those experiments the fusion protein was expressed in vaccinia virus. we have now refined the system so that large amounts of highly immunogenic particles can be produced using a simple bacterial expression system. we describe the expression of three different viral epitopes as chimeric particles that induce good antibody responses to each epitope afte ... | 1990 | 1693163 |
| tyrosine protein kinase activity of the hz4-feline sarcoma virus p80gag-kit-transforming protein. | the hardy-zuckerman 4 feline sarcoma virus (hz4-fesv), isolated from a feline fibrosarcoma, is a replication defective acute transforming feline retrovirus that originated by transduction of feline c-kit sequences with feline leukemia virus (felv). the v-kit sequences of the hz4-fesv, a segment of 1106 nucleotides, correspond to sequences of the cytoplasmic domain of the c-kit receptor kinase. the hz4-fesv is known to encode an 80-kilodalton protein with felv gag and kit determinants. the p80gag ... | 1990 | 1697669 |
| prophylactic and therapeutic effects of phosphonoformate against feline leukemia virus in vitro. | phosphonoformate (pfa), a noncompetitive inhibitor of reverse transcriptase (rt), inhibited feline leukemia virus (felv) infection of 2 feline cell lines and inhibited progeny virus rt activity in a chronically felv-infected cell line. feline leukemia virus infection of 3201 cells, an felv-negative lymphoma cell line, was inhibited by greater than 70% at a concentration of only 1 microm pfa and by greater than 90% at concentrations of 64 to 256 microm pfa, as evidenced by rt activity. however, f ... | 1991 | 1724122 |
| use of immunomodulators as an aid to clinical management of feline leukemia virus-infected cats. | | 1991 | 1724773 |
| antibody response to reverse transcriptase in cats infected with feline immunodeficiency virus. | the antibody response in cats to feline immunodeficiency virus (fiv) reverse transcriptase (rt) was followed for 3 years. eight of the nine cats used in this study produced reverse transcriptase-inhibiting (rti) antibodies. relative inhibitory means of 2.9%, 18.4%, 33%, and 47% were found 6, 12, 24, and 36 months, respectively, after infection with fiv. the enzyme activity was suppressed by greater than or equal to 78% with the use of 100 micrograms of fiv-associated igg. the rti antibodies were ... | 1991 | 1726399 |
| retroviral pseudotypes produced by rescue of a moloney murine leukemia virus vector by c-type, but not d-type, retroviruses. | human hos cells containing a moloney murine leukemia virus (mo-mlv) recombinant genome were infected by a panel of retroviruses. the c-type viruses simian sarcoma associated virus, feline leukemia virus subgroup b, and the feline endogenous virus rd114 were able to form pseudotypes with the mo-mlv genome, which transferred a selectable marker gene to target cells; however, human t cell leukemia virus-1 and the d-type viruses mason-pfizer monkey virus and simian retrovirus-1 failed to rescue the ... | 1992 | 1733113 |
| some viral and protozool diseases in the european wildcat (felis silvestris). | ten european wildcats (felis silvestris) were examined at necropsy and an additional 23 were examined clinically for evidence of viral diseases in scotland. two plasma samples taken from live free-living wildcats showed positive elisa reactions to feline leukemia antigen. a feline leukemia virus of subgroup a was isolated from one of these samples, taken from a wildcat in north-western scotland. no antibodies to feline coronavirus or feline immunodeficiency virus were detected in any sample. thr ... | 1991 | 1758037 |
| evaluation of a biologic response modifier derived from serratia marcescens: effects on feline macrophages and usefulness for the prevention and treatment of viremia in feline leukemia virus-infected cats. | normal feline bone marrow-derived macrophages released maximum concentrations of interleukin-6, tumor necrosis factor, and interleukin-1 when stimulated with imuvert (cell technology inc, boulder, co, usa) at dosages of 1.0 microgram/ml, 5.0 micrograms/ml, and 10.0 micrograms/ml, respectively. when imuvert was administered to healthy adult cats, significant elevations in rectal temperature and neutrophil counts were observed 10 and 24 hours after each treatment. weekly treatment with imuvert fai ... | 1991 | 1768375 |
| nuclear factor 1 activates the feline leukemia virus long terminal repeat but is posttranscriptionally down-regulated in leukemia cell lines. | a recombinant feline leukemia virus (felv) proviral clone (t17t-22) with a long terminal repeat (ltr) which differs from prototype felv by a point mutation within a conserved nuclear factor 1 (nf1)-binding motif in the ltr enhancer domain was found to be poorly expressed after dna transfection. the nf1 point mutation reduced in vitro protein binding as assessed by gel shift analysis and reduced promoter activity significantly (2- to 10-fold). however, the degree of promoter impairment due to the ... | 1991 | 1848314 |
| retrovirus-induced feline pure red blood cell aplasia: pathogenesis and response to suramin. | feline leukemia virus, subgroup c/sarma (felv-c/sarma) induces pure red blood cell aplasia in cats. although erythroid (bfu-e and cfu-e) and granulocyte/macrophage (cfu-gm) progenitors are infected with this virus, only erythropoiesis is impaired. two to 3 weeks before the onset of anemia, cfu-e become undetectable in marrow cultures while earlier erythroid progenitors (bfu-e) persist, suggesting that felv-c/sarma (presumably via its envelope glycoprotein gp70) inhibits the differentiation of bf ... | 1991 | 1849031 |
| disease progression and viral genome variants in experimental feline leukemia virus-induced immunodeficiency syndrome. | a fatal immunodeficiency syndrome with clinical and pathologic features similar to human aids is inducible in cats by experimental inoculation with a specific strain of feline leukemia virus (felv) called felv-faids. the course of the feline disease is characterized by an age-dependent prodromal period during which a non-disease-specific, common form of proviral dna is detected in bone marrow. preceding clinical onset of immunodeficiency is production of high levels of specific, pathogenic varia ... | 1991 | 1850796 |
| ocular disease in felv-positive cats: 11 cases (1981-1986). | a total of 147 cats positive for felv were retrospectively studied to determine the incidence of ocular disease. of those cats, 97 had clinical cases of the disease and 50 were artificially infected with the virus. the incidence of ocular disease among felv-positive cats with clinical signs of disease was less than 2%, and represented less than 0.1% of the total feline cases for the 5-year period studied. the only ocular findings that could be associated with felv were pupillary and motility abn ... | 1991 | 1851738 |
| isolation of felv from a wild felid (felis silvestris). | | 1991 | 1852080 |
| national felv/fiv awareness project. | | 1991 | 1852082 |
| concurrent infection with toxoplasma gondii and feline leukemia virus. antibody response and oocyst production. | four adult cats (two testing positive and two negative for feline leukemia virus felv) were fed toxoplasma gondii tissue cysts collected from the brains of mice. two control cats (1 felv+, 1 felv-) were not fed cysts. the cats infected with t. gondii shed thousands of oocysts but remained clinically and physically normal, with hemograms and clinical chemistry values essentially unchanged irrespective of their felv status. infection with felv did not increase the duration of oocyst shedding. at n ... | 1991 | 1920257 |
| cytologic, microbiologic, and biochemical analysis of bronchoalveolar lavage fluid obtained from 24 healthy cats. | twenty-four healthy cats underwent bronchoscopy and bronchoalveolar lavage to determine the normal cytologic environment of the lower respiratory tract of cats. initial screening to ensure the health of the study population included complete histories, physical examinations, thoracic radiography, cbc, serologic tests for feline leukemia virus, feline immunodeficiency virus, and occult heartworm, and sugar and baermann fecal flotation. in 18 cats, protected catheter brush samples of airway secret ... | 1991 | 1928912 |
| therapy of presymptomatic felv-induced immunodeficiency syndrome with azt in combination with alpha interferon. | azt inhibited replication of an immunodeficiency-inducing strain of feline leukemia virus (felv-faids) in vitro at concentrations as low as 0.005 microgram/ml. this antiviral activity was augmented an additional 25-30% when azt was combined with human recombinant alpha-interferon (2b) (ifn alpha). administration of azt alone or in combination with ifn alpha, beginning at the time of exposure to a 100% persistent viremia-inducing dose of felv-faids, abrogated the progression of viral infection an ... | 1990 | 1964030 |
| induction of feline immunodeficiency syndrome by feline leukemia virus: pituitary and adrenocortical dysfunctions. | seven young cats were injected with feline leukemia virus (felv); six of them became viremic. all of the viremic cats developed aids-related symptoms, i.e. lymphopenia, neutropenia, thymic atrophy, and wasting syndrome, along with an altered pituitary and adrenocortical function. these symptoms closely resemble human aids induced by hiv. it was discovered that, after 2 weeks of infection, the average amount of plasma adrenocorticotropic hormone (acth) detected in the infected cats was reduced by ... | 1990 | 1965124 |
| a serologic survey of oklahoma cats for antibodies to feline immunodeficiency virus, coronavirus, and toxoplasma gondii and for antigen to feline leukemia virus. | a serologic survey was done on 618 cat sera submitted to the oklahoma animal disease diagnostic laboratory between july 1, 1987 and june 30, 1988. the samples were collected from clinically normal and sick cats. the sera were tested for the presence of antibodies to feline immunodeficiency virus by a commercial immunoassay, to a coronavirus by an indirect fluorescent antibody test, and to toxoplasma gondii by a commercial latex agglutination test and for the presence of feline leukemia virus ant ... | 1990 | 1965583 |
| effect of administration of diethylcarbamazine on murine leukemia virus (cas-br-m) infected mice. | previous studies indicate that decreased serum viral infectivity and viral antigen levels follow oral administration of diethylcarbamazine (dec) in feline leukemia virus infected cats, even though dec has not been shown to exhibit in vitro antiviral activity. in this investigation, dec was given by oral administration or (single dose) ip injection to murine leukemia virus (cas-br-m) inoculated mice to permit evaluation of its effect on viral-induced central nervous system disease. the survival o ... | 1990 | 1967004 |
| biological activities of a synthetic peptide composed of two unlinked domains from a retroviral transmembrane protein sequence. | we report several biological activities of a synthetic peptide whose sequence contains the highly conserved region of feline leukemia virus transmembrane protein (tm) synthetically linked to another short tm-derived sequence particularly rich in polar positive residues. this 29-amino-acid peptide blocked [3h]thymidine uptake 30 to 50% by concanavalin a-stimulated cd4(+)--but not cd8(+)-enriched murine splenocytes. maximal suppression was detected at 12.5 micrograms (3 microm) to 75 micrograms (1 ... | 1990 | 1969500 |
| natural killer cell activity of rhesus macaques against retrovirus-pulsed cd4+ target cells. | rhesus peripheral blood mononuclear cells (pbmc) fail to demonstrate natural killer (nk) activity against the human t-cell lines cem, cem x 174, or sup-t1. however, these cell lines could act as nk-sensitive target cells if they were pulsed with heat-inactivated, whole simian immunodeficiency virus (siv). the ability of these siv-pulsed t-cell lines to act as nk-sensitive target cells was directly related to the relative density of cd4 on their surface. target cell generation was inhibited by pr ... | 1990 | 1975194 |
| lymphocyte subset alterations and viral determinants of immunodeficiency disease induction by the feline leukemia virus felv-faids. | the felv-faids strain of feline leukemia virus consistently induces fatal immunodeficiency. to investigate the immunopathogenesis and viral genetic determinants responsible for the induction of immunodeficiency disease in vivo, we have generated chimeras between the two major viral genomes in the original virus isolate, designated common form clone 61e and major variant clone 61c, which were molecularly cloned directly from dna of the same animal and tissue. each of three 61e/c chimeras, contain ... | 1990 | 1976822 |
| asymptomatic feline leukemia virus carrier cats have an enhanced susceptibility to feline immunodeficiency virus-induced disease. | | 1990 | 1980900 |
| lymphocyte population changes in cats naturally infected with feline immunodeficiency virus. | feline immunodeficiency virus (fiv) is associated with feline acquired immunodeficiency syndrome (faids) and has been suggested as a model for hiv-induced human aids. the most obvious immunological defect in hiv infection is a reduction in cd4+ cell numbers and an inversion of the cd4:cd8 ratio. to determine whether the same is true in fiv infection, we analyzed by flow cytometry using a panel of monoclonal antibodies to feline lymphocyte populations the cd4:cd8 ratios in cats naturally infected ... | 1990 | 1982410 |
| serological survey of the iriomote cat (felis iriomotensis) in japan. | the iriomote cat (felis iriomotensis) was first discovered on iriomote island in the yaeyama islands of japan in 1965. ten male and 11 female adult cats were captured during the 6 yr period from 1983 to 1988. these were examined for evidence of viral and mycoplasmal infections. neither mycoplasma sp. nor ureaplasma sp. were detected in swab samples of oropharyngeal and urogenital regions. a foamy virus was isolated from the oropharyngeal swab of a female cat examined in 1988. feline leukemia vir ... | 1990 | 2110982 |
| sensitivity, specificity, and predictive values of clinease-virastat saliva test for feline leukemia virus infection. | detection of virus in saliva using a commercial enzyme-linked immunosorbent assay (elisa), clinease-virastatr, was compared to evidence of felv infection by the indirect immunofluorescent antibody assay (ifa) and plasma elisa. the sensitivity and specificity of the saliva elisa were derived by comparison to ifa and plasma elisa in 103 cats from a large colony in new york state. the sensitivity of the saliva test in relation to ifa and plasma elisa was approximately 100% and 93%, respectively. th ... | 1990 | 2152775 |
| feline leukemia virus infection as a potentiating cofactor for the primary and secondary stages of experimentally induced feline immunodeficiency virus infection. | preexistent feline leukemia virus (felv) infection greatly potentiated the severity of the transient primary and chronic secondary stages of feline immunodeficiency virus (fiv) infection. of 10 felv-fiv carrier cats, 5 died of experimentally induced fiv infection, compared with 2 deaths in 10 cats infected only with felv and 1 death in 7 cats infected only with fiv. fiv-infected cats with preexistent felv infections developed severe depression, anorexia, fever, diarrhea, dehydration, weight loss ... | 1990 | 2153226 |
| randomized blind trial of a commercial felv vaccine. | a randomized blind trial of a commercial felv vaccine was conducted to evaluate its performance in cats under conditions of long-term natural exposure. seventy-nine nonviremic, seronegative cats were randomized into 2 groups. cats were given 3 doses of either felv vaccine or placebo (killed rabies virus vaccine) sc at weeks 0, 3, and 9 of the trial. six weeks later, 44 known-viremic cats were added to the colony. cats were housed in a single large room and food dishes and litter pans were used i ... | 1990 | 2154424 |
| molecular cloning and characterization of a defective recombinant feline leukaemia virus associated with myeloid leukaemia. | the gm1 strain of feline leukaemia virus (felv) was isolated from a naturally occurring case of myeloid leukaemia and induces severe haematopoietic abnormalities, including myeloblastic leukaemia, on inoculation into cats. molecular clones of felv-gm1 proviruses were obtained and studied by restriction enzyme mapping, blot hybridization and partial dna sequence analysis. two types of clone were isolated; the first was a replication-competent felv of subgroup a, resembling other low or minimally ... | 1990 | 2155287 |
| evaluation of immunosuppressive effect and efficacy of an improved-potency feline leukaemia vaccine. | an inactivated feline leukaemia vaccine was tested to determine if process improvements would permit it to be effectively used in a two-dose primary regimen versus the three-dose regimen required for a previous vaccine. twenty-five cats were vaccinated with two subcutaneous doses given 3 weeks apart. vaccinates and controls were artificially immunosuppressed to enhance susceptibility to challenge, and inoculated with virulent feline leukaemia virus (felv) 2 weeks after the second dose. following ... | 1990 | 2156386 |
| structural diversity and nuclear protein binding sites in the long terminal repeats of feline leukemia virus. | the long terminal repeat u3 sequences were determined for multiple feline leukemia virus proviruses isolated from naturally occurring t-cell tumors. heterogeneity was evident, even among proviruses cloned from individual tumors. proviruses with one, two, or three repeats of the long terminal repeat enhancer sequences coexisted in one tumor, while two proviruses with distinct direct repeats were found in another. the enhancer repeats are characteristic of retrovirus variants with accelerated leuk ... | 1990 | 2157050 |
| inhibition of phorbol ester-induced neutrophil chemiluminescence by felv. | receptor-mediated activation is accompanied by phospholipid metabolism and by calcium fluctuation resulting in a chemiluminescence (cl) response in the neutrophil. this pathway involves activation of protein kinase c (pkc) and the nadph oxidase. artificial stimulants such as phorbol esters, specifically 12-o-tetradecanylphorbol-13-acetate (tpa), circumvent the receptor-mediated pathway and activate pkc resulting in a measurable cl response. neutrophils from feline leukemia virus (felv) exposed c ... | 1990 | 2158290 |
| prevalence of disease in nonviremic cats previously exposed to feline leukemia virus. | feline leukemia virus status and antibody titer to feline oncornavirus-associated cell membrane antigen (focma) were determined on plasma from 183 outpatient cats and 61 cats from 2 closed, felv-positive, multiple-cat households. cats with focma antibody titer had a significantly (p less than 0.02) higher prevalence of history of disease than did cats without focma antibody. diseases included upper respiratory tract infections, abscesses, ear infections, lower urinary tract infections, gastroint ... | 1990 | 2158493 |
| feline immunodeficiency virus and feline leukemia virus infections and their relationships to lymphoid malignancies in cats: a retrospective study (1968-1988). | sera from 353 cats with naturally occurring feline leukemia virus (felv) infection were collected in boston, los angeles, new york city, and seattle between 1968 and 1988. these sera were retrospectively assayed by enzyme-linked immunosorbent assay for antibodies to feline immunodeficiency virus (fiv). fifty-one (14.4%) of the felv-positive sera had antibodies to fiv, indicating dual oncovirus and lentivirus infections. fiv infections were confirmed by western blot analysis, antibodies against t ... | 1990 | 2159993 |
| efficacy of a feline leukemia virus vaccine in a natural exposure challenge. | a commercial feline leukemia virus (felv) vaccine was evaluated in a natural exposure system. all kittens were negative for felv antigen on two enzyme-linked immunosorbent assay (elisa) tests and one indirect immunofluorescence antibody (ifa) test before vaccination or exposure. twenty-three kittens were vaccinated subcutaneously at nine and 12 weeks of age. the vaccinated kittens and 14 unvaccinated littermates were housed in an infected environment starting at 14 weeks. the kittens were expose ... | 1990 | 2160531 |
| purine metabolism in feline lymphomas. | deficiency of the purine metabolic enzyme adenosine deaminase causes severe immunodeficiency. retroviruses have been reported to decrease the activity of adenosine deaminase, and many retroviruses, including feline leukemia virus, cause immunodeficiency. levels of purine metabolic enzymes including adenosine deaminase and consequences of adenosine deaminase inhibition were investigated in feline leukemia virus-infected fresh tumor cells and infected and uninfected cell lines. no evidence of viru ... | 1990 | 2161136 |
| a feline large granular lymphoma and its derived cell line. | a lymphoma cell line (mcc) was derived from an abdominal mass from a 13-yr-old castrated male cat. the cells resemble natural killer precursor cells, have membrane-bound granules, and are positive for chloroacetate esterase, alpha-naphthyl butyrate esterase, and tartrate-resistant acid phosphatase activities. the mcc cells are negative for rearranged feline t-cell receptor genes, negative for feline t-cytotoxic antigen, ia, and surface mu, tau, and lambda chains and do not form e-rosettes. the m ... | 1990 | 2161827 |
| flvi-1, a common integration domain of feline leukemia virus in naturally occurring lymphomas of a particular type. | a locus in feline dna, termed flvi-1, which may play an important role in the natural induction of lymphomas by feline leukemia virus (felv) was identified. examination of a bank of 21 naturally occurring felv-positive feline lymphomas revealed that felv proviral integration occurs at flvi-1 in four independent tumors (19%). independent integrations occurred within a 2.4-kilobase region of flvi-1, the probability of which by random chance can be estimated as 10(-16). several lines of evidence, i ... | 1990 | 2161948 |
| molecular cloning of feline leukemia provirus genomes integrated in the feline large granular lymphoma cells. | feline leukemia virus (felv) is a horizontally transmitted agent of the domestic cat which is known to be associated with wide spectrum of diseases of the hematopoietic system. in the present study, proviral dnas of felv proviruses were examined in the tumor cells of natural killer cell lineage which is very rare in cats. in the chromosomal dna of the tumor cells, 5 distinct bands corresponding to exogenous felv provirus genomes were detected by digestion with ecori which does not cut most felv ... | 1990 | 2162159 |
| zidovudine toxicity to cats infected with feline leukemia virus. | feline leukemia virus (felv) infection of cats is a model for the acquired immunodeficiency syndrome in humans. the toxicity of zidovudine was evaluated in spf cats experimentally infected with felv. at initiation of the zidovudine study, all cats were antibody positive for felv antigens but clinically asymptomatic. four cats were also viremic. thirteen, 6- to 10-month-old cats were divided into five dosage groups and given zidovudine po at 0, 7.5, 15, 30, or 60 mg/kg daily in three equally divi ... | 1990 | 2163339 |
| should cats be vaccinated for feline leukemia? | | 1990 | 2163809 |
| zidovudine in combination with alpha interferon and interleukin-2 as prophylactic therapy for felv-induced immunodeficiency syndrome (felv-faids). | zidovudine (3'-azido-3'-deoxythymidine; azt) inhibited replication of an immunodeficiency-inducing strain of feline leukemia virus (felv-faids) in vitro at concentrations of 0.5-0.005 micrograms/ml. a 25-30% additional antiviral effect was achieved in vitro when azt was combined with human recombinant alpha interferon 2a (ifn alpha). oral administration of azt (20 mg/kg three times daily) to cats resulted in plasma concentrations of 3 micrograms/ml at 2 h post-administration with a t1/2 of appro ... | 1990 | 2164083 |
| an unusual retrovirus-like sequence identified in human dna. | the human genome contains many different types of endogenous proviruses and retrovirus-like elements. an unusual element of this kind has been isolated from human dna on the basis of its relatedness to the integrase-coding domain of the pol gene of feline leukaemia virus (felv). the element, termed hs5, is related to felv only over a short region of 81 nucleotides predicted to encode the carboxyl terminus of the felv integrase protein, p46pol. the region of relatedness between hs5 and felv ident ... | 1990 | 2165140 |
| epizootiologic association between feline immunodeficiency virus infection and feline leukemia virus seropositivity. | five hundred twenty-one feline serum samples submitted to the texas veterinary medical diagnostic laboratory between nov 1, 1988, and jan 31, 1989 were tested for antibody to feline immunodeficiency virus (fiv) by use of an elisa. the prevalence of fiv infection in this population was 11.3% (95% confidence interval: 8.6 to 14.0%). serologic test results for felv were available for 156 of the 521 cats. a significant (p = 0.008) association between fiv infection and felv seropositivity was observe ... | 1990 | 2166726 |
| characterization and significance of delayed processing of the feline leukemia virus felv-faids envelope glycoprotein. | felv-faids, an immunodeficiency-inducing isolate of feline leukemia virus, is composed of a pathogenic but replication-defective genome (molecular clone 61c) and a replication-competent but non-immunodeficiency-inducing variant genome (molecular clone 61e). the chimeric virus eecc, composed of the 5' gag-pol of 61e fused to the env-3' ltr of 61c, also induces immunodeficiency. the 61c (or eecc) gp80 can be distinguished from that of 61e on the basis of antigenic recognition, size, and rate of po ... | 1990 | 2166820 |
| in vitro and in vivo evidence that the antiviral activity of 2',3'-dideoxycytidine is target cell dependent in a feline retrovirus animal model. | 2',3'-dideoxycytidine (ddc) was evaluated for prophylactic antiviral activity in vitro and in vivo, using the feline leukemia virus (felv)-cat animal model. in vitro antiviral activity of ddc against felv was dependent upon the target cell used for infection. ddc (5 to 10 microm) inhibited felv infection of feline lymphoid cells by greater than 80%, while 6.07 to 12.13 microm ddc was required to similarly inhibit infection of feline fibroblasts. however, 43 to 384 microm ddc was needed to inhibi ... | 1990 | 2167039 |
| [feline immunodeficiency virus in switzerland: clinical aspects and epidemiology in comparison with feline leukemia virus and coronaviruses]. | serum samples from 1421 domestic cats (561 healthy, 860 sick) were tested for fiv-, felv- and coronavirus infection. the results were stored in a computer data base and compared with epidemiologic data and clinical findings. all 3 infections were significantly more prevalent in sick than healthy cats: fiv was found in 0.7% of healthy and 3.4% of sick cats. for felv the prevalence was 3.0% and 13.0% and for coronavirus 21% and 36.2%, respectively. fiv-infected cats were mostly male (73%); no sex ... | 1990 | 2167513 |
| reference intervals for feline cerebrospinal fluid: biochemical and serologic variables, igg concentration, and electrophoretic fractionation. | reference intervals are reported for feline csf biochemical and serologic variables, igg concentration, and electrophoretic fractionation, derived from 58 clinically normal adult cats that did not have histologic lesions of the cns. there was no apparent effect of age on any variable. the csf total protein concentration was significantly (p = 0.012) greater in males than in females, but all other variables were unaffected by gender. the only variable that had a statistically significant correlat ... | 1990 | 2167619 |
| effect of toxoplasma lysate antigen (tla) on feline cytotoxicity against felv positive lymphoma cells. | the cytotoxic activities of feline spleen cells treated with toxoplasma lysate antigen (tla) were assayed against feline leukemia virus (felv)-producing lymphoma. fl74 cells, and xenogeneic target lymphoma, mouse yac-1 cells. the tla treatments were performed in vivo alone, in vitro alone, and in vivo plus in vitro, respectively. in vivo plus in vitro treatments with tla induced a marked augmentation in cytotoxic activity of spleen cells to fl74 cells. the treatment with tla in vivo alone showed ... | 1990 | 2167995 |
| existence of feline immunodeficiency virus infection in japanese cat population since 1968. | | 1990 | 2168001 |
| fv-1 restriction of endogenous feline c-type rd114 virus genome phenotypically mixed with ecotropic murine leukemia viruses. | endogenous feline leukemia rd114 virus genome rendered capable of infecting mouse cells by phenotypic mixing with an ecotropic murine leukemia virus (mulv) exhibited the fv-1 restriction pattern of the ecotropic murine virus. however, rd114 genomes phenotypically mixed with ecotropic mulv showed one-hit dose-response kinetics, even when titrated with murine cells with the restricted fv-1 phenotype. | 1990 | 2168865 |
| recombinant feline herpesviruses expressing feline leukemia virus envelope and gag proteins. | we constructed recombinant feline herpesviruses (fhvs) expressing the envelope (env) and gag genes of feline leukemia virus (felv). expression cassettes, utilizing the human cytomegalovirus immediate-early promoter, were inserted within the thymidine kinase gene of fhv. the felv env glycoprotein expressed by recombinant fhv was processed and transported to the cell surface much as in felv infection, with the exception that proteolytic processing to yield the mature gp70 and p15e proteins was les ... | 1990 | 2168977 |
| feline retroviruses: a brief review. | representatives of all three retrovirus subfamilies are recognized in the cat: feline leukaemia virus (an oncovirus), feline syncytium-forming virus (a spumavirus) and feline immunodeficiency virus (a lentivirus). each of these is briefly reviewed. | 1990 | 2169669 |
| immunosuppressive actions of retroviruses. | the immunosuppressive properties of retroviruses were first demonstrated by old et al. we later showed that gross passage a retrovirus superinfection in mice resulted in decreased antibody production and diminished allograft rejection. we have studied in some detail the immunosuppression which occurs subsequent to infection with feline leukemia virus (felv) as characterized by profoundly depressed t and b lymphocyte responses and decreased production of gamma-interferon. injection of staphylococ ... | 1990 | 2170777 |
| lymphatic tissue changes in aids and other retrovirus infections: tools and insights. | based on immunohistochemistry, in situ hybridization, and electron microscopy, lymphatic tissue changes in human immunodeficiency virus (hiv) and other retroviral infections represent different stages of a dynamic process progressing from hyperplasia to atrophy. the germinal centers (gc) function early as a virus reservoir in both hiv and feline leukemia virus infection, which also produces lymphadenopathy, severe immune impairment, and death from opportunistic infections. core proteins of hiv c ... | 1990 | 2170778 |
| the polymerase chain reaction (pcr): a valuable method for retroviral detection. | although the detection of antibodies to a specific pathogen is used initially as the assay of choice, direct detection of human retroviruses is difficult. first, only a small fraction of cells are infected in the peripheral blood and lymphatic tissue may serve as a reservoir for infection. second, infected cells may harbor only a small number of copies of the viral sequences. third, a latent infection marked by transcriptional dormancy is often established thereby obviating the use of proteins o ... | 1990 | 2170779 |
| feline immunodeficiency virus, feline leukaemia virus, toxoplasma gondii, and intestinal parasitic infections in taiwanese cats. | a population consisting of 70 breeder cats, 43 clinical cases, and 16 feral cats was examined for the presence of toxoplasma gondii, feline immunodeficiency virus (fiv), and feline leukaemia virus (felv). no oocysts of t. gondii were observed in 96 faecal samples; faecal samples were not available from the feral cats. other intestinal parasites identified included isospora felis (three cats), isospora rivolta (five), dipylidium canium (two), toxocara cati (four), toxascaris leonina (one), and an ... | 1990 | 2171713 |
| type c retroviral expression in spontaneous feline olfactory neuroblastomas. | three cases of spontaneous olfactory neuroblastoma (onb) in domestic cats were morphologically and immunocytochemically characterized. diagnostic light microscopic features included flexner and homer-wright rosettes, while ultrastructurally the cells had neuritic processes, intracellular intermediate filaments, and intercellular junctions. immunocytochemically, the tumors stained positively for neuron-specific enolase, cytokeratins, and s-100 protein antigens. in each case, a key finding was the ... | 1990 | 2174630 |
| prevalence of antibody to hantavirus in some cat populations in britain. | | 1990 | 2177930 |
| feline retrovirus infections. | | 1990 | 2178110 |
| origins and characteristics of pathogenic variants of feline leukaemia virus. | | 1990 | 2178111 |
| pathogenic mechanisms of immunodeficiency syndrome and aplastic anemia induced by feline leukemia viruses. | | 1990 | 2178112 |
| the felv and siv aids pathogenesis models: search for and analysis of molecularly defined pathogens. | | 1990 | 2178113 |
| vaccination against feline retroviruses. | | 1990 | 2178114 |
| evaluation of humoral immunity tests in felv infected cats. | | 1990 | 2178116 |
| alpha interferon (2b) in combination with zidovudine for the treatment of presymptomatic feline leukemia virus-induced immunodeficiency syndrome. | the therapeutic efficacies of human recombinant alpha interferon (ifn-alpha), ifn-alpha plus zidovudine (azt), and azt alone were evaluated in presymptomatic cats with established feline leukemia virus (felv)-acquired immunodeficiency syndrome (faids) infection and high levels of persistent antigenemia. subcutaneous injection of 1.6 x 10(6) u of human recombinant ifn-alpha 2b per kg delivered peak concentrations in plasma of 3,600 u/ml at 2 h postadministration with a half-life of elimination of ... | 1990 | 2178336 |
| iscoms. | the common problem for defined purified antigens or antigen determinants has been to make them immunogenic regardless of whether they are produced conventionally, produced as cloned genetechnology products or chemically synthesized. the first problem is to get the protective antigen into a submicroscopic particle where the antigen is presented in several copies, i.e. as a multimer. for some antigens it seems also necessary to enhance the immunogenicity with an adjuvant. the immunostimulating com ... | 1990 | 2205974 |
| human recombinant interleukin-2 induces maturation and activation signals for feline eosinophils in vivo. | immunotherapy, with interleukin-2 (il-2) or il-2 plus lymphokine-activated killer (lak) cells, has been used to treat cancer and acquired immunodeficiency syndrome (aids) in man. similarities between feline leukemia virus (felv) infection in the cat and human immunodeficiency virus (hiv) infection in man have prompted immunotherapeutic studies in the cat. to develop baseline data on hematological responses to infused il-2, cats were given daily (1-14 days) i.v. injections of 5 x 10(4) u/kg of re ... | 1990 | 2230598 |
| the iscom: an immunostimulating system. | to make purified antigens highly immunogenic, they have to be presented in several copies in the form of a microscopic or submicroscopic particle. this is the case, regardless of whether the antigens are obtained by isolation from conventional microorganisms, or from gene-manipulated cells, or synthesized. in the iscom, the antigens are attached as multimers to a 40-nm cage-like particle with a built-in adjuvant. the antigens in iscoms are rapidly transported from the injection site to the drain ... | 1990 | 2283159 |
| hematologic manifestations of feline immunodeficiency virus infection. | studies were done on 53 cats with community-acquired infection with the feline immunodeficiency virus (fiv) to determine if hematologic abnormalities were comparable with those observed in patients seropositive for the human immunodeficiency virus (hiv). nine cats were asymptomatic, 24 had clinical symptoms equivalent to aids-related complex (arc), and 20 had aids-like disease. hematologic abnormalities were detected in 75% (40 of 53) of fiv-seropositive cats, and multiple concurrent cytopenias ... | 1990 | 2400806 |
| subunit vaccines against exogenous retroviruses: overview and perspectives. | vaccines prepared from purified viral envelope complexes are effective against certain animal model tumors induced by exogenous retroviruses. related viruses have recently been isolated from humans and obviously cause adult t-cell leukemia and the acquired immunodeficiency syndrome. knowledge accumulated in experiments with subunit vaccines against animal retroviruses could help to develop immunopreventive regimens against human retroviruses. | 1985 | 2410114 |
| molecular analysis of several classes of endogenous feline leukemia virus elements. | five recombinant dna clones of endogenous feline leukemia virus-related dna sequences were isolated by screening a lambda phage genomic library of cat placental dna with a probe specific to the gag-pol region of infectious feline leukemia virus. the clones containing retroviral long terminal repeat-like sequences demonstrated the existence of different size classes of endogenous elements in the cat genome, including those of nearly full length in which the gag region is heterogeneous but all of ... | 1985 | 2415715 |
| from jenner to jerne: towards idiotype vaccines. | | 1986 | 2422113 |
| characterization of a newly established feline lymphoma-derived cell line (bkd) lacking t and b cell surface markers. | a new feline lymphoma-derived cell line, designated bkd, was isolated from an anterior mediastinal tumor. cells of this line were characterized as lymphoid based on morphology, the lack of intracellular esterase and peroxidase activity, and absence of phagocytic function. in contrast with other established feline lymphoma-derived cell lines, cells of the bkd line lack characteristics of both feline t-cells and b-cells in that they neither form rosettes with guinea pig erythrocytes nor have demon ... | 1986 | 2423498 |
| analysis of retroviral pol gene products with antisera raised against fusion proteins produced in escherichia coli. | portions of the pol gene of moloney murine leukemia virus (mulv) were expressed as fusion proteins in escherichia coli, and the purified proteins were used to elicit antibodies in escherichia coli, and the purified proteins were used to elicit antibodies in rabbits. the sera were used to examine the mature pol gene products contained in virion particles and identified the reverse transcriptase and a second protein, p46pol, encoded by the 3' portion of the gene. the p46 protein was not phosphoryl ... | 1986 | 2426463 |
| localization of neutralizing regions of the envelope gene of feline leukemia virus by using anti-synthetic peptide antibodies. | we synthesized 27 synthetic peptides corresponding to approximately 80% of the sequences encoding gp70 and p15e of gardner-arnstein feline leukemia virus (felv) subtype b. the peptides were conjugated to keyhole limpet hemocyanin and injected into rabbits for preparation of antipeptide antisera. these sera were then tested for their ability to neutralize a broad range of felv isolates in vitro. eight peptides elicited neutralizing responses against subtype b isolates. five of these peptides corr ... | 1987 | 2431166 |
| infection of feline lymphoid cells with feline leukemia virus in culture. | an in-vitro system for infection of cat t lymphocytes with feline leukemia virus (felv) was developed. for establishment of this system, felv was inoculated in vitro into concanavalin-a stimulated primary lymphoid cells and long-term cultured t cells grown with interleukin-2 (il-2) from various feline lympho-hematopoietic organs. during serial cultivation with il-2, felv group-specific antigen (gsa) was detected 5-6 weeks after infection in the primary cultures, and 1 week after infection in the ... | 1987 | 2439849 |
| natural feline leukemia virus variant escapes neutralization by a monoclonal antibody via an amino acid change outside the antibody-binding epitope. | we have molecularly cloned a natural variant of feline leukemia virus subtype b. this isolate is unique in that it is not neutralized by a monoclonal antibody which neutralized all other feline leukemia virus isolates tested, including members of the a, b, and c subtypes. western immunoblotting indicated that the monoclonal antibody was less able to bind to the gp70 of the resistant isolate (designated lambda b1) than to the gp70s of susceptible viruses. nucleotide sequence analysis of the envel ... | 1987 | 2444714 |
| immunotherapy for feline leukemia, using staphylococcal protein a or heterologous interferons: immunopharmacologic actions and potential use. | | 1988 | 2453494 |
| the aids virus can take on many guises. | | 1988 | 2457946 |
| major structural polypeptides of retrovirus produced by a suncus murinus mammary tumor cell line and type d retrovirus share interspecies antigenic determinants. | constitutive polypeptides of retrovirus produced by a suncus murinus mammary tumor cell line (sm-mtv) were characterized by immunofluorescence and immunoblotting. the major structural polypeptide of sm-mtv, molecular weight 44/43k, immunologically cross reacted with the structural polypeptides of mason-pfizer monkey virus (mpmv) (molecular weights 27k and 12/10k). sm-mtv constitutive polypeptides did not show antigenic relatedness with those of the following mammalian retroviruses: murine mammar ... | 1988 | 2460996 |
| induction of anti-viral immune response by immunization with monoclonal anti-idiotype antibodies directed to private idiotopes. | syngeneic monoclonal anti-idiotypic antibodies were raised against idiotopes on neutralizing monoclonal antibodies with specificity for feline leukemia virus and canine parvovirus. the anti-idiotypic antibodies were shown to recognize paratope-related private idiotopes. mice were injected with the monoclonal anti-idiotypic antibodies and the sera of these mice were screened for antiviral reactivities. antibodies to both feline leukemia and canine parvovirus could be induced as determined by elis ... | 1989 | 2482029 |
| posttranslational modifications distinguish the envelope glycoprotein of the immunodeficiency disease-inducing feline leukemia virus retrovirus. | the envelope glycoprotein (gp70) of a molecularly cloned, replication-defective feline leukemia virus (felv-faids clone 61c) carries determinants for induction of fatal immunodeficiency disease, whereas the gp70 of its companion replication-competent, probably parent virus (clone 61e) does not. immunoprecipitation analysis of the extracellular glycoproteins of 61e and eecc, a replication-competent viral construct composed of the 61c env and 3' long terminal repeat fused to the 61e gag-pol genes, ... | 1989 | 2535725 |
| feline lymphomas: immunological and cytochemical characterization. | the immunological and cytochemical phenotypes of five primary feline lymphomas and six feline lymphoma lines are reported. thymic lymphomas induced by the rickard strain of felv (felv-r) are of prothymocyte or (immature) cortical thymocyte origin, as these express terminal deoxynucleotidyl transferase, the guinea pig erythrocyte rosette receptor, ia antigens, partial cortisone sensitivity, and nonspecific esterase. lymphomas associated with other strains of felv form rosettes with guinea pig ery ... | 1989 | 2535958 |
| in vitro erythrocytopathic activity of an aplastic anemia-inducing feline retrovirus. | although feline leukemia viruses (felv) cause a spectrum of proliferative and anti-proliferative diseases in vivo, in vitro studies demonstrating cell lineage-specific pathogenic properties of feline retroviruses have been rare. we describe here an efficient in vitro system that demonstrates the selective cytopathic effect of a molecularly cloned anemogenic felv (felv-sarma-subgroup c; fsc) on erythroid progenitor cells. forty-eight-hour coculture of normal feline bone marrow mononuclear cells w ... | 1989 | 2536328 |
| colony forming t lymphocyte deficit in the development of feline retrovirus induced immunodeficiency syndrome. | the identification and molecular cloning of a feline leukemia virus (felv) isolate (felv-faids) that consistently produces immunodeficiency syndrome has allowed prospective investigation of events that occur in the prodromal phase of disease. using a t-lymphocyte colony forming assay (t-cfu-ic) we have demonstrated that a drastic depletion of circulating t-cfu-ic prefigures the development of clinical immunodeficiency disease in inoculated cats and correlates with the appearance and replication ... | 1989 | 2537113 |
| feline immunodeficiency virus infection in cats of japan. | a seroepidemiologic survey for feline immunodeficiency virus (fiv) infection was conducted in japan. between june and december 1987, individual sera (n = 3,323) were submitted by veterinary practitioners from many parts of the country. specimens were from 1,739 cats with clinical signs suggestive of fiv infection and from 1,584 healthy-appearing cats seen by the same practitioners. the overall fiv infection rate among cats in japan was 960/3,323 cats (28.9%). the infection rate was more than 3 t ... | 1989 | 2537270 |
| serologic response of domestic ferrets (mustela putorius furo) to canine distemper and rabies virus vaccines. | nine unrelated 12-week-old naive domestic ferrets (mustela putorius furo) were used to evaluate the serologic responses to commercial canine distemper virus (cdv) and rabies virus (rv) vaccines. five of the ferrets (group 1) were inoculated 3 times at 2-week intervals with a multivalent modified-live virus vaccine of canine cell-line origin, containing cdv and an inactivated rv vaccine. four of the ferrets (group 2) were inoculated once with the multivalent modified-live virus vaccine containing ... | 1989 | 2537273 |
| feline leukemia virus and feline immunodeficiency virus infections in a cat with lymphoma. | lymphoma was diagnosed in a 7-year-old domestic cat found to be infected with felv and feline immunodeficiency virus (fiv). the cat was affected by chronic disorders suggestive of immunosuppression, including gingivitis, periodontitis, keratitis, and abscesses. despite treatment, peripheral keratitis of the left eye progressed, resulting in uveitis, chronic glaucoma, and eventual corneal rupture. microscopic retinal and optic disk pathologic processes also were suspected. abnormal jaw movements ... | 1989 | 2537274 |
| interleukin-2 suppression in cats naturally infected with feline leukemia virus. | feline peripheral blood lymphocytes (pbls) produce interleukin-2 (il-2) when stimulated with concanavalin a (con a) or the combination of the ca2+ ionophore a23187 (a2) plus the phorbol ester phorbol-12-myristate-13-acetate (pma). to determine the status of t helper cell function in cats naturally infected with feline leukemia virus (felv), pbls from 19 normal cats and 49 felv-infected (34 asymptomatic and 15 symptomatic) cats were tested for their ability to produce il-2 in response to con a or ... | 1989 | 2537886 |
| vaccines against tumor antigens. | effective vaccines against tumor antigens have not yet been produced. however, immunomodulators hold much promise in cancer therapy. such treatments will probably involve using combinations of various immunomodulators together with activated killer cells. development of vaccines against tumor-causing viruses seems to be a rational approach to preventing the onset of virus-induced cancers. it seems that efficient vaccines have already been developed for hepatitis b virus; such vaccines have the p ... | 1989 | 2539001 |
| structure, origin, and transforming activity of feline leukemia virus-myc recombinant provirus ftt. | a myc-containing recombinant feline leukemia provirus, designated ftt, was molecularly cloned from the cat t-cell lymphoma line f422. its transforming activity, as well as the nucleotide sequence of the 3' 2.7 kilobases of ftt, including v-myc, was determined. the predicted v-myc protein differs from feline c-myc by three amino acid changes and is truncated by two amino acids at the carboxyl terminus. comparison with feline leukemia virus (felv), feline c-myc, and other felv proviruses indicates ... | 1989 | 2539507 |
| nucleotide sequence and distinctive characteristics of the env gene of endogenous feline leukemia provirus. | nucleotide sequence analysis of the env gene of two different endogenous feline leukemia virus (felv) loci, cfe-6 and cfe-16, of domestic cats revealed the following characteristics. (i) both proviruses contain an open reading frame in the env region; (ii) whereas the full complement of the exogenous felv env is generally present in cfe-6 dna, it is truncated in cfe-16 dna such that the 5' half of the gp70 domain and the untranslated region 3' to the p15e domain have been fused by an internal de ... | 1989 | 2539525 |