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isolation of mammalian type c rna virus cross-reactive antigen and antibody by immuno-affinity chromatography. 197549291
interspecies antigenic determinants of the reverse transcriptases and p30 proteins of mammalian type c viruses.the major internal structural proteins (p30) of type c viruses isolated from several mammalian species were studied by radioimmunoprecipitation and competitive radioimmunoassays. three antigenically distinguishable sets of interspecies determinants could be demonstrated by both methods. one set of determinants shared by viruses of rodent origin (mouse and rat) can be detected readily in feline leukemia viruses but not in other type c viral groups. the p30 proteins of murine viruses also contain ...197549443
[proceedings: some biochemical properties of bovine leukemia virus]. 197550808
evolution of type c viral genes: origin of feline leukemia virus.reiterated gene sequences related to the rna of feline leukemia virus (felv) are detected in all tissues of domestic cats and their close felis relatives but not in more distantly related felis species. partially homologous viral gene sequences are found in rodent, and particularly rat, dna. together with the immunologic relationships observed between felv and endogenous rodent type c viruses, the results lead to the conclusion that felv-related genes were transmitted from a rodent to cat ancest ...197552892
immune response to leukemia virus and tumor-associated antigens in cats.cats represent an unusually valuable model for studying the role of the immune response to leukemia, lymphoma, and other mesodermal neoplasms. the agents that cause spontaneous feline leukemias, lymphomas, and fibrosarcomas, the feline leukemia and sarcoma viruses, are well characterized. a specific tumor cell membrane antigen, designated the feline oncornavirus-associated cell membrane antigen (focma) has also been described. feline leukemia and feline sarcoma viruses are antigenically indistin ...197656224
expression of feline leukaemia virus antigens on cat lymphoma cells: kinetics of biosynthesis. 197769678
sarcoma virus-induced transformation specific antigen: presence of antibodies in cats that were naturally exposed to leukemia virus. 197988797
anemia associated with feline leukemia virus infection in cats.the types of anemia associated with natural and experimental feline leukemia virus (felv) infection in cats were investigated. in one experiment, 10 kittens were inoculated neonatally with jarrett felv-1, an isolate of subgroup a; 6 developed anemia a few weeks later. this anemia was characterized by macrocytosis, normoblastosis, increased erythropoiesis in the bone marrow, and extramedullary hematopoiesis in the spleen. anemia was transient and nonfatal and occurred before the onset of lympoid ...1975163317
establishment of two canine sarcoma cell lines: productive infection with feline leukemia virus.two canine sarcoma cell lines (11028, 11031) were established in vitro and have been transferred 213 and 306 times, respectively, since 1970. these cell lines had a chromosome pattern consistent with their canine origin. both cultures were infected with feline leukemia virus (felv), which caused a morphologic and karyotypic changes. the cells became rounded after infection with felv and both cultures showed the presence of a single, large, acrocentric chromosome considered to be a marker chromos ...1975169374
feline oncornavirus-associated cell membrane antigen. iv. antibody titers in cats with naturally occurring leukemia, lymphoma, and other diseases.cats with naturally occurring leukemia and lymphoma had low or negative humoral antibody titers to the feline oncornavirus-associated cell membrane antigen (focma). geographic differences were seen in the relative frequencies of various forms of lymphoproliferative neoplasms. lymphatic leukemia and thymic lymphoma were most common in boston, whereas alimentary lymphoma was most frequent in glasgow. no significant differences were found in geometric mean focma antibody titers for the various form ...1975169377
editorial: leukaemia in animals and man. 1975169460
complement-fixation-inhibition as a test for antibodies in cats and humans to c-type rna tumor virus antigen.the complement-fixation-inhibition (cfi) test was evaluated as a means of detecting humoral antibodies in cat sera and in human sera to mammalian c-type rna virus interspecies antigen(s). cfi antibody titers of greater than or equal 1:2 were detected in sera from all tumor bearing (23) and normal cats (23), however, sera from most germ free cats were negative. when the same cat sera were tested for blocking antibody by the paired radioiodine labeled antibody technique the correlation between the ...1975169819
horizontal transmission of feline leukemia virus in cats.traditionally, cancer has not been considered an infectious disease although some multiple cases of leukemia in man and cattle have been reported. the discovery that feline lymphosarcoma was associated with an rna virus (feline leukemia virus(felv)) meant that infectious transmission of the disease was a possibility. the critical question was whether the predominant method of transmission from one animal to another was 'vertical' (via the gametes) or 'horizontal' (via contagion or infection). a ...1975169834
sarcomas induced in rats by feline rna virus. 1975169839
viral diseases of cats: current concepts. 1976179185
feline leukemia virus research- an update. 1975179729
prevention of the contagious spread of feline leukaemia virus and the development of leukaemia in pet cats. 1976183148
feline anemia. 1976183337
biologic and immunologic response of cats to experimental infection with feline leukemia virus. 1975183666
the epidemiology of feline leukemia virus infection. 1975183672
comparative epidemiological aspects of naturally occurring malignant lymphoma in domestic cats and rhesus monkeys. 1975183676
surface properties of mammalian c type viruses. 1975183712
lymphocyte mitogen reactivity in feline leukemia virus-infected cats and identification of feline t and b lymphocytes. 1975183735
expression of feline type-c virus in normal and tumor tissues of the domestic cat.tumor and normal tissues from domestic cats were examined for felv and rd-114 specific nucleic acids and proteins. virus-positive tissues showed a 100- to 200-fold higher level of felv and a 200- to 400-fold higher level of felv p30 than virus-negative tumors and normal cat tissues. in contrast, the levels of rd-114 viral rna and p30 antigen were comparable in the majority of tumorous and normal tissues examined. when the dna of these tissues was examined for felv-related sequences, the virus-po ...1976186414
feline oncornavirus-associated cell membrane antigen. vi. cytotoxic antibody in cats exposed to feline leukemia virus.feline leukemia virus (felv)-infected specific pathogen-free (spf) cats, normal uninfected spf cats, and healthy cats from leukemic households were tested for antibody reactive to the feline oncornavirus-associated cell membrane antigen (focma)-containing target cell line fl-74 by microcytotoxicity and indirect membrane immunofluorescence. of the infected spf animals, 81% showed concordant reactivity for the two tests. in contrast, only 55% of the healthy cats known to be naturally exposed to fe ...1976186623
feline leukemia virus infection: age-related variation in response of cats to experimental infection.sixty-seven specific-pathogen-free cats of various ages (newborn, 2 wk, 1 mo, 2 mo, 4 mo, and 1 yr) were inoculated ip with either the rickard (r) or the kawakami-theilen (kt) strain of feline leukemia virus (felv). susceptibility to felv was judged by induction of a) felv group-specific antigens (gsa) in leukocytes, b) felv-related disease, c) antibody to feline oncornavirus-associated cell membrane antigen (focma), and d) virus-neutralizing (vn) antibody. susceptibility to felv-decreased with ...1976187771
horizontal transmission of feline leukemia virus under natural conditions in a feline leukemia cluster household.ten post-weanling 4-month-old cats, designated "tracers", were placed in a feline leukemia cluster household to determine the efficiency of horizontal transmission of feline leukemia virus (felv). the tracer cats were confirmed as negative for prior exposure to felv. following the placement in the leukemia cluster environment, the tracer cats were serologically monitored at intervals of 3-6 weeks for a total period of 1 year. the tests employed included the detection of felv using fixed-cell imm ...1977188773
horizontal transmission of feline leukemia virus under experimental conditions.thirty-seven specific-pathogen-free (spf) cats ranging from newborn to 1 year were inoculated with the rickard strain of feline leukemia virus (felv). each inoculated cat shared a cage with a control spf cat for 40 weeks post inoculation. after 4-5 weeks, 20 of the inoculated cats became group-specific antigen (gsa)-positive; the other 17 remained gsa-negative but developed virus neutralizing and feline oncornavirus cell membrane-associated antigen antibody titers. seventeen of the control cats ...1977189052
felv epidemiology in los angeles cats: appraisal of detection methods.we investigated the reliability of the fixed cell indirect fluorescent antibody (ifa) peripheral blood smear test as an index of systemic infection with felv. positive results with this test were found to correlate well with detectable felv p30 antigen in bone-marrow smears by ifa, in serum and tissue by competition immunoassays, and with type-c particles in bone marrow or spleen by electron microscopy. most cats with lymphoma, anemia or infectious peritonitis were positive for felv and showed a ...1977191415
retinal neoplasia and dysplasia. i. induction by feline leukemia virus.feline leukemia virus, a naturally occurring c-type virus (oncorna virus), was injected systemically and intraocularly into fetal and newborn kittens. a light microscopy study of the resultant ocular tumor changes was carried out. one animal developed an intraocular tumor of apparent retinal origin. eight animals showed intraocular neoplastic cell infiltration. the most common ocular change observed was retinal dysplasia. sequential histologic examination of enucleated eyes showed diffuse intrao ...1977191424
feline leukemia virus. its related diseases and control. 1977191976
rejectability of virus-induced tumors and nonrejectability of spontaneous tumors: a lesson in contrasts.in contrast to the excellent surveillance against tumors induced by the ubiquitous viruses in their natural host species, spontaneous tumors developing naturally, without experimental interference, evoke little or no rejection reaction. this may be viewed in relation to the natural history of tumors. in most cases, tumors evolve in several steps, with a successful of clonal variants following each other, characterized by increasing independence of host regulations (including immune restrictions) ...1977194366
passive immunity to feline leukemia: evaluation of immunity from dams naturally infected and experimentally vaccinated.antibodies against feline leukemia virus (felv) and the feline oncornavirus-associated cell membrane antigen (focma) were transferred from pregnant cats to their suckling kittens. all of these kittens were protected against infection and oncogenesis by virulent felv when challenged at 2 weeks of age. suckling kittens acquired 25 to 100% of maternal virus-neutralizing and focma titers by 3 days of age, and titers underwent linear decay to undetectable levels by 2 to 3 months of age. focma antibod ...1977194840
endogenous rd-114 virus genome expression in malignant tissues of domestic cats.endogenous xenotropic cat type c virus (rd-114)- and infectious feline leukemia virus (felv)-specific gene expressions were measured in spontaneous sarcomas carcinomas, and nonmalignant cat tissues by molecular hybridization for virus-specific rna and competition radio-immunoassays for the major internal protein (p30) of these two viruses. the results indicate that rd-114 gene expression in sarcomas and carcinomas at both rna and p30 levels is significantly higher than histologically normal tiss ...1977197261
inhibition of normal lymphocyte mitogenic reactivity by serum from feline leukemia virus-infected cats.the effect of serum from 12 cats with lymphosarcoma induced by feline leukemia virus (felv) on the response of normal cat peripheral blood lymphocytes to phytomitogen-induced blastogenesis was studied. the majority of felv sera, when tested at a concentration of 20% of the incubation medium, caused a 40 to 70% reduction in the mean blastogenic response to concanavalin a compared to the response obtained with a similar concentration of normal feline serum. results with pokeweed mitogen were simil ...1977198125
[comparative study of oncornavirus type d polypeptides]. 1977198961
protection of kittens from feline leukaemia virus infection by maternally-derived antibody. 1977199981
reiteration frequency of feline type c viral genomes in homologous and heterologous host cell dna.differences in the multiplicity of proviral sequences of two feline endogenous viruses, rd-114 and felv, in homologous and heterologous host dna were examined by viral cdna hybridization using cellular dna fractionated with respect to reiteration frequency. the endogenous proviral dnas in cat cells were fractionated predominantly with intermediate-repeated sequences, while rd-114 proviral dna in virus-infected human cells was fractionated together with unique-sequence dna. these differences were ...1978201591
feline oncornavirus-associated cell membrane antigen: evidence for an immunologically crossreactive feline sarcoma virus-coded protein.the feline oncornavirus-associated cell membrane antigen (focma) acts as a target for natural immuno-surveillance against tumor development in the cat. in the present study, mink and rat cells nonproductively transformed by feline sarcoma virus (fesv) were shown to express focma as well as 5'-terminal feline leukemia virus (felv) gag gene proteins, p15 and p12. in contrast, such cells lack detectable levels of other felv gag gene-coded proteins or the env gene product, gp70. focma, p15, and p12 ...1977202959
cat leukemia and the cluster controversy. 1978204405
a portion of the feline leukaemia virus genome is not endogenous in cat cells.although viral sequences closely related to feline leukaemia virus are represented in multiple copies in cellular dna of all domestic cats, a specific fraction was present only in the virus-infected cells. this fraction was detected by viral cdna enriched by a prior absorption of a total complementary dna (cdna) transcript with normal cat liver dna. the recycled cdna hybridized well with the cellular dna of virus-infected cells, but to a lesser extent with dna from uninfected cat cells. the prob ...1978210130
potentiation of the neurtalization of feline leukaemia virus in hypotonic medium.the neutralization of feline leukaemia virus could be enhanced by performing the reaction in hypotonic medium. absorption of antibody by virus specific antigens was also made more sensitive under these conditions.1978211186
the occurrence of feline leukaemia virus neutralizing antibodies in cats. 1978212375
characterization of a feline sarcoma virus-coded antigen (focma-s) by radioimmunoassay.a radioimmunoassay has been developed that detects a unique antigen encoded by the genome of the feline sarcoma virus (fesv). pseudotype viral particles containing an fesv-specific polyprotein (p85) were used both as a source of antigen and to prepare specific antisera in rabbits. because p85 contains antigens related to two structural proteins (p15 and p12) of feline leukemia virus (felv), antibodies directed to these were adsorbed with purified felv proteins. the adsorbed rabbit antiserum boun ...1978212755
feline sarcoma virus-coded polyprotein: enzymatic cleavage by a type c virus-coded structural protein.a purified 15,000-molecular-weight (mr) prague strain rous sarcoma virus gag gene-coded structural protein, p15, was shown to enzymatically cleave the previously described 130,000 mr feline sarcoma virus-coded polyprotein, pr130. cleavage products included proteins ranging in molecular weight from 12,000 to 110,000. the specificity of this cleavage reactivity was indicated by the fact that, under similar conditions, neither purified type c viral structural proteins nor nonviral proteins such as ...1979219252
modifications of the immunofluorescence assay for feline leukemia virus group-specific antigens.observations and minor modifications are presented concerning the immunofluorescence assay for feline leukemia virus (felv) group-specific antigens (gsa) in blood cells of cats. data are given regarding absorption of goat felv gsa antiserum in vivo in cats, absorption of the antiserum in vitro with feline blood cells, and the comparative efficacy of various chemical fixatives in preservation of felv gsa for immunofluorescent staining. the best results were obtained with in vitro absorption of an ...1978219732
applied viral immunology. 1978220771
immunologic methods for the detection of humoral and cellular immunity.a variety of immunologic techniques have been introduced during the past few years. many of these techniques are being applied to clinical specimens in an attempt to help the practicing veterinarian make a diagnosis. the introduction of new techniques requires extensive testing with clinically normal and diseased patients. it is essential for the practicing veterinarian to understand that the techniques available for the detection of immunologic disorders in the dog and cat are not routine diagn ...1978220772
nature and distribution of feline sarcoma virus nucleotide sequences.the genomes of three independent isolates of feline sarcoma virus (fesv) were compared by molecular hybridization techniques. using complementary dnas prepared from two strains, sm- and st-fesv, common complementary dna's were selected by sequential hybridization to fesv and feline leukemia virus rnas. these dnas were shown to be highly related among the three independent sarcoma virus isolates. fesv-specific complementary dnas were prepared by selection for hybridization by the homologous fesv ...1979225544
distribution of feline leukemia virus dna sequences in tissues of normal and leukemic domestic cats. 1979227157
[feline leukemia: recent developments on the causes and immunoprevention of the disease (author's transl)]. 1978230008
[feline leukemia complex]. 1979230018
hematologic abnormalities preceding myeloid leukemia in three cats.cytopenia were recognized in three cats infected with feline leukemia virus. in one cat, marrow blast cells were increased in number, and a diagnosis of aleukemic leukemia was made. the disease progressed slowly for 3 1/2 months before terminating in acute myelomonocytic leukemia, recognized as a blast crisis in blood. in the other two cats, neutropenia and altered granulopoiesis in bone marrow preceded development of myeloid leukemia.1979289225
characterization of feline glomerulonephritis associated with viral-induced hematopoietic neoplasms.light, electron, and immunofluorescence microscopy on tissues from 63 domestic cats revealed that glomerulonephritis occurred in almost one third of cats with hematopoietic neoplasms of the type linked with feline leukemia virus (felv). glomerular lesions were of the immune complex type with subepithelial, subendothelial, and mesangial dense deposits and reticular aggregates, similar to the nephropathy associated with systemic lupus erythematosus in humans. evidence that the glomerular lesions m ...1978677265
feline leukemia virus: pathophysiology, prevention, and treatment. 19921312884
comparison of the viral promoter activities in feline cell lines (crfk and fcwf-4 cells). 19921313705
prevalence of feline leukemia virus and antibodies to feline immunodeficiency virus in cats in norway.serum samples from 224 norwegian cats were analyzed for the presence of feline leukemia virus (felv) p27 common core antigen, and for antibodies to feline immunodeficiency virus (fiv). ninety specimens originated from the serum bank at the central referral clinic at the norwegian college of veterinary medicine, which had been collected during the years 1983-1989; 67 sera were submitted from veterinarian practitioners; while 67 sera originated from cats presented for euthanasia. the cats were cla ...19921316024
pathogenesis of feline leukemia virus t17: contrasting fates of helper, v-myc, and v-tcr proviruses in secondary tumors.a naturally occurring feline thymic lymphosarcoma (t17) provided the unique observation of a t-cell antigen receptor beta-chain gene (v-tcr) transduced by a retrovirus. the primary tumor contained three classes of feline leukemia virus (felv) provirus, which have now been characterized in more detail as (i) v-tcr-containing recombinant proviruses, (ii) v-myc-containing recombinant proviruses, and (iii) apparently full-length helper felv proviruses. the two transductions appear to have been indep ...19921316466
studies in feline long-term marrow culture: hematopoiesis on normal and feline leukemia virus infected stromal cells.to study the effects of feline leukemia virus (felv) on the hematopoietic microenvironment, a two-step feline long-term marrow culture (ltmc) system was developed and characterized. the adherent, stromal layer of these cultures is composed of fibroblastoid cells (50% to 80%), macrophages (10% to 30%), fat cells (10% to 20%), and large, polygonal cells that express muscle actin (1% to 2%). when fresh, enriched marrow mononuclear cells (mmnc) were added to 3-week-old irradiated stromal cultures, n ...19921322201
feline leukemia virus subgroup c phenotype evolves through distinct alterations near the n terminus of the envelope surface glycoprotein.feline leukemia viruses (felvs) belonging to the c subgroup induce aplastic anemia in domestic cats and have the ability, unique among felv strains, to proliferate in guinea pig fibroblasts in tissue culture. previous studies have shown that the pathogenic and host range specificity of a prototype molecular clone of felv-c [felv-sarma-c (fsc)] colocalize to a region encoding the 3' 73 amino acids of the pol gene product and the n-terminal 241 amino acids of the envelope surface glycoprotein name ...19921326757
chromosome abnormalities and oncogenesis in cat leukemias.chromosome abnormalities are found in feline leukemia virus (felv)-infected tumor cells as well as in tumor cells free of the virus. three cell lines derived from tumors in the domestic cat (felis catus), two of thymic origin and one of multicentric lymphoma origin, were analyzed cytogenetically to determine whether the felv virus was associated with chromosomal abnormalities in these tumor cell lines. one thymic tumor and the multicentric lymphoma were felv infected. the other thymic tumor cell ...19921336708
association between feline immunodeficiency virus antibodies and host characteristics in finnish cats.toward the end of 1989 the largest private veterinary laboratory in finland (vet/lab) began using a commercial combined elisa test for feline immunodeficiency virus (fiv) antibodies and feline leukemia virus (felv) antigens (cite combo). the overall proportion of fiv seropositive feline samples was 5% during the 22 month study period. the number of tests performed increased slowly while the positive test results decreased with time (7% in 1990 and 4% in 1991). the decrease in prevalence was assu ...19921336930
retrovirus infections in non-domestic felids: serological studies and attempts to isolate a lentivirus.an african lioness from the zoo of zurich had to be euthanized because of an inoperable tumor. the serum tested negative for feline leukemia virus (felv) p27 antigen by enzyme-linked immunosorbent assay (elisa) but was strongly positive for feline immunodeficiency virus (fiv) antibodies by elisa and western blot. when her only offspring and mate were tested for fiv, high antibody titers to fiv were also found in their serum. lymphocytes were prepared from these two lions on different occasions a ...19921337398
tumor necrosis factor alpha levels in cats experimentally infected with feline immunodeficiency virus: effects of immunization and feline leukemia virus infection.tumor necrosis factor alpha (tnf alpha) levels were determined by enzyme-linked immunosorbent assay (elisa) and by cell culture bioassay in supernatants of lipopolysaccharide-stimulated feline monocyte cultures and in cat serum samples. there was a good correlation between the results obtained by the two methods. from the fact that tnf alpha was neutralized quantitatively by antibodies to human tnf alpha in feline monocyte supernatants and in feline sera, it was concluded that feline tnf alpha i ...19921337403
use of two virustatica (azt, pmea) in the treatment of fiv and of felv seropositive cats with clinical symptoms.in the present study the therapeutic efficacy and the side effects of two antiretroviral compounds used in human acquired immunodeficiency syndrome (aids) research, 3'-azido-2',3'-dideoxythymidine (azt, zidovudine, retrovir) and 9-(2-phosphonylmethoxyethyl)adenine (pmea), were investigated in the treatment of cats naturally infected with feline immunodeficiency virus (fiv) and cats naturally infected with feline leukemia virus (felv). azt was administered subcutaneously at a dose of 5 mg kg-1 bo ...19921363008
immunization-induced decrease of the cd4+:cd8+ ratio in cats experimentally infected with feline immunodeficiency virus.in a previous experiment a group of 15 specified pathogen free (spf) cats were experimentally infected with a swiss isolate of feline immunodeficiency virus (fiv). a group of 15 spf cats served as fiv negative controls. nine cats of each group were vaccinated with a recombinant feline leukemia virus (felv) vaccine, six cats in each group with a placebo vaccine. all vaccinated cats developed high antibody titers to felv and were protected against subsequent felv challenge infection. in both contr ...19921363009
cell lines produce factors that induce fetal hemoglobin in human bfue-derived colonies.established cell lines were screened for secretion of activities than can stimulate fetal hemoglobin (hbf) production in adult burst-forming unit-erythroid (bfue) cultures. conditioned media from four cell lines, a human teratocarcinoma, an osteosarcoma, a bladder cell carcinoma, and feline leukemia virus (felv) a-infected feline fibroblasts (fef-a cells), consistently increased the relative production of fetal globin in bfue-derived colonies. in vitro translation of rna from these cells in xeno ...19921384795
enzyme-linked immunosorbent assays for the detection of toxoplasma gondii-specific antibodies and antigens in the aqueous humor of cats.serum and aqueous humor samples, collected from 14 clinically normal cats and 96 cats with clinical evidence of intraocular inflammation, were assayed with elisa for toxoplasma gondii-specific immunoglobulin m (igm), t gondii-specific igg, t gondii-specific antigens, total igg, and total igm. additionally, serum was assayed with elisa for feline leukemia virus p27 antigen and antibodies against the feline immunodeficiency virus as well as with an immunofluorescent antibody assay for antibodies a ...19921429123
[the effectiveness of paramunization for the control of feline coryza].20 cats in a cat home were treated prophylactically and therapeutically with baypamun hk. the animals were allocated into three groups as described. 7 freshly admitted clinically healthy cats were treated prophylactically on day 1, 2 and 9 with 1 ml baypamun hk (group i). 7 cats, who already were allocated for one year in the home and were sick of the feline respiratory disease complex were treated as described for group i (group ii). 6 further cats, who also showed symptoms of the feline respir ...19921524577
use of 8-methoxypsoralen and long wavelength ultraviolet radiation for decontamination of platelet concentrates.transmission of viral diseases through blood products remains a problem in transfusion medicine. we have developed a photochemical decontamination system (pcd) for platelet concentrates (pc) utilizing treatment with long wavelength ultraviolet radiation (uva, 320-400 nm) and 8-methoxypsorlan (8-mop). this system is capable of inactivating 25-30 logs/hour of bacteria e. coli or s. aureus, 6 logs/hour of bacteriophage fd, 0.9 log/hour of bacteriophage r17, and 1.1 logs/hour of feline leukemia viru ...19921617193
genetically-engineered subunit vaccine against feline leukaemia virus: protective immune response in cats.a recombinant retroviral subunit vaccine has been developed that successfully protects cats from infectious feline leukaemia virus (felv) challenge. the antigen used is a non-glycosylated protein derived from the envelope glycoprotein of felv subgroup a, expressed in escherichia coli. this recombinant protein, rgp70d, includes the entire exterior envelope protein gp70, plus the first 34 amino acids from the transmembrane protein p15e. the vaccine consists of purified rgp70d absorbed on to alumin ...19911647576
anti-idiotypic antibodies to feline leukemia virus: an approach for retroviral immunization strategies.the present study describes an approach to the development and use of anti-idiotypic antibodies as a possible immunization strategy to prevent retroviral infection. the rationale for using anti-idiotypes (anti-ids) to try to elicit an antigenic-specific immune response is examined, and the production and characterization of polyclonal and monoclonal anti-ids are described. several techniques were used to determine antigenic mimicry and anti-id subtypes. the potential use of anti-ids in feline le ...19911648360
pathological features of lymphoid tissues in cats with natural feline immunodeficiency virus infection.a range of tissues from a total of 17 cats naturally infected with the feline immunodeficiency virus was examined histologically. in 11 cases, chronic inflammatory lesions were present in various tissues including, most commonly, the intestine, brain and lung. extensive inflammation in the intestinal wall was present in seven of the cats. no particular bacterial organisms were demonstrated in these inflammatory lesions. a range of changes was present in the lymph nodes, including hyperplasia, at ...19911651959
early therapy of feline leukemia virus infection (felv-faids) with 9-(2-phosphonylmethoxyethyl)adenine (pmea).cats infected with molecularly cloned felv-faids develop an immunodeficiency syndrome characterized by persistent antigenemia, decline in circulating cd4+ t lymphocytes, and impaired t-cell-dependent immune responses and opportunistic infection. we evaluated the capacity of pmea to inhibit the replication of felv-faids in vitro and to inhibit the progression of felv-faids infection in vivo. we found that pmea inhibited replication of felv-faids by greater than or equal to 50% at concentrations o ...19911663730
early events in the immunopathogenesis of feline retrovirus infections.feline leukemia virus and feline immunodeficiency virus (fiv) are lymphotropic retroviruses that cause a wide range of diseases in domestic cats. although it is known that both viruses are capable of infecting t lymphocytes and that infected cats are lymphopenic, it was not known how infection with either virus might alter specific lymphocyte subpopulations. using a panel of monoclonal antibodies to feline lymphocyte subpopulations, we examined, by use of flow cytometric analysis, lymphocyte cha ...19911666073
development of the immunofluorescent antibody test for detection of feline leukemia virus infection in cats.studies of the immunodetection of various microorganisms by various assay systems indicated that the most specific and sensitive assays are immunofluorescence, radioimmunoassay, and immunoblot analysis (western blot), followed by sensitive but less specific elisa and agglutination assays and, finally, by even less sensitive but very specific virus isolation and double immunodiffusion techniques. the first test for the clinical detection of felv infection in pet cats was the immunofluorescent ant ...19911666076
enzyme-linked immunosorbent assay methods for detection of feline leukemia virus and feline immunodeficiency virus.enzyme-linked immunosorbent assays have been widely used for diagnosis of felv and feline immunodeficiency virus (fiv) infections. various elisa kits for felv are available from several manufacturers. although these tests are configured in a variety of formats, they are all direct antigen-detection systems for the viral core protein p27. on the other hand, elisa for fiv exposure detects specific feline antibody to fiv. basic immunoassay principles and the application of elisa technology used in ...19911666077
how well do serodiagnostic tests predict the infection or disease status of cats? 19911666079
neoplasia associated with feline immunodeficiency virus infection in cats of southern california.between 1988 and 1991, feline immunodeficiency virus (fiv) infection status was evaluated in 1,160 cats examined at an oncology referral and general practice in los angeles, california. twenty-nine (2.5%) cats were fiv positive. neoplasia was present in 18 of the 29 (62%) cats. sampling for neoplasia was intentionally biased in the oncology referral group. however, 33% (6/18) of fiv-infected cats with neoplasia originated from the general practice. three neoplastic processes were observed; myelo ...19911666082
comparison of four test kits for feline leukemia virus antigen.the sensitivity and specificity of 4 commercial felv elisa kits, using blood, were compared with results of virus isolation from blood and immunofluorescent antibody (ifa) testing on blood. significant differences were not found among the 4 elisa kits. marked decrease in sensitivity of the elisa kits was detected when virus isolation was used as the standard of positivity rather than the ifa test. virus isolation was a more sensitive indicator of early infection, with marked discrepancy among re ...19911666085
evaluation of feline leukemia virus diagnostic tests available for in-office use by veterinarians.blood samples from cats were tested for felv group-specific antigen by use of an indirect immunofluorescent antibody (ifa) test, elisa, or both. several elisa kits were evaluated as they would be used in a veterinary clinic, and some elisa kits were compared with an ifa test for agreement of results. good agreement of results was evident among the commercially available elisa kits; results for most blood samples were clearly negative or decidely positive. occasionally, test results were equivoca ...19911666088
evaluation of a killed, whole virion feline leukemia virus vaccine. 19911666093
development of a genetically engineered vaccine against feline leukemia virus infection.a genetically engineered subunit vaccine against felv infection was developed. the protective immunogen in the vaccine was a purified recombinant protein containing the entire amino acid sequence of felv subgroup a gp70 envelope protein. the optimal adjuvant was determined to be a highly purified saponin, qs-21, derived from quillaja saponaria molina. a vaccine formulation containing the recombinant protein, qs-21, and aluminum hydroxide was tested in specific-pathogen-free kittens and was shown ...19911666096
evaluation of efficacy and safety of an inactivated virus vaccine against feline leukemia virus infection.an inactivated virus vaccine was developed for prevention of felv infection in domestic cats. when given in 2 doses, 3 weeks apart, to cats that were greater than or equal to 9 weeks old at the time of first vaccination, the vaccine prevented persistent viremia from developing in 132 of 144 (92%) vaccinates after oronasal challenge exposure with virulent felv. in contrast, persistent viremia developed after oronasal challenge exposure with felv in 39 of 45 (87%) age-matched nonvaccinated control ...19911666097
comparative efficacy of three commercial feline leukemia virus vaccines against methylprednisolone acetate-augmented oronasal challenge exposure with virulent virus.three commercial felv vaccines, (a, b, and c) were purchased on the open market and administered to 8- to 20-week-old specific-pathogen-free kittens, according to manufacturers' instructions. a similar group of nonvaccinated kittens served as controls. all kittens were challenge-exposed oronasally with virulent felv 4 weeks after the final vaccination. serum samples were monitored for felv-p27 antigenemia using an elisa at 1- to 2-week intervals for at least 16 weeks after the last day of challe ...19911666102
management of healthy feline leukemia virus-positive cats. 19911666105
prevalence of feline immunodeficiency virus and feline leukemia virus infections in random-source cats.retroviral serologic profiles were generated for 506 random-source cats (felis catus) that were received by our facility during a twenty-month period. feline leukemia virus antigens were detected in plasma samples from 26 (5.1%) of the cats. antibodies to feline immunodeficiency virus were present in 24 (4.7%) of the samples tested. a single cat (0.2%) was positive for both viruses. neither gender nor vendor correlation with retroviral seropositivity could be demonstrated.19911667194
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 ...19901690524
use of immunomodulators as an aid to clinical management of feline leukemia virus-infected cats. 19911724773
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 ...19911726399
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 ...19911758037
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 ...19911848314
national felv/fiv awareness project. 19911852082
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 ...19911928912
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 ...19901964030
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 ...19901965583
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 ...19901967004
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 ...19901982410
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 ...19902158290
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 ...19902159993
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