RESUMO
Select humans and animals control persistent viral infections via adaptive immune responses that include production of neutralizing antibodies. The precise genetic basis for the control remains enigmatic. Here, we report positional cloning of the gene responsible for production of retrovirus-neutralizing antibodies in mice of the I/LnJ strain. It encodes the beta subunit of the non-classical major histocompatibility complex class II (MHC-II)-like molecule H2-O, a negative regulator of antigen presentation. The recessive and functionally null I/LnJ H2-Ob allele supported the production of virus-neutralizing antibodies independently of the classical MHC haplotype. Subsequent bioinformatics and functional analyses of the human H2-Ob homolog, HLA-DOB, revealed both loss- and gain-of-function alleles, which could affect the ability of their carriers to control infections with human hepatitis B (HBV) and C (HCV) viruses. Thus, understanding of the previously unappreciated role of H2-O (HLA-DO) in immunity to infections may suggest new approaches in achieving neutralizing immunity to viruses.
Assuntos
Anticorpos Neutralizantes , Antígenos HLA-D/metabolismo , Antígenos de Histocompatibilidade Classe II/metabolismo , Imunidade Humoral , Vírus do Tumor Mamário do Camundongo/imunologia , Vírus Rauscher/imunologia , Infecções por Retroviridae/imunologia , Animais , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/metabolismo , Apresentação de Antígeno/genética , Biologia Computacional , Feminino , Predisposição Genética para Doença , Antígenos HLA-D/genética , Células HeLa , Hepatite B/imunologia , Hepatite B/transmissão , Hepatite C/imunologia , Hepatite C/transmissão , Antígenos de Histocompatibilidade Classe II/genética , Humanos , Imunidade Humoral/genética , Masculino , Camundongos , Camundongos Endogâmicos , Camundongos Knockout , Mutação/genética , Polimorfismo Genético , Infecções por Retroviridae/transmissãoRESUMO
The antitumor effectiveness of cyclophosphamide (CTX) and other chemotherapeutics was shown to rely not only on direct cytotoxicity but also on immunogenic tumor cell death and systemic immunomodulatory mechanisms, including regulatory T cell (Treg) depletion, Th1 cell polarization, type I interferon (IFN) and proinflammatory cytokine production. IFN regulatory factor (IRF)-1 is a transcriptional regulator of IFNs and IFN-inducible genes, involved in the control of Th1 and Treg differentiation and in sterile inflammation. Aim of this study was to explore the role of IRF-1 in CTX-induced antitumor effects and related immune activities. This study shows for the first time that IRF-1 is important for the antitumor efficacy of CTX in mice. Moreover, experiments in tumor-bearing C57BL/6 mice showed that Irf1 gene expression in the spleen was transiently increased following CTX administration and correlated with the induction of Th1 cell expansion and of Il12p40 gene expression, which is the main Th1-driving cytokine. At the same time, CTX administration reduced both Foxp3 expression and Treg cell percentages. These effects were abrogated in Irf1-/- mice. Further experiments showed that the gene and/or protein expression of caspase-1, iNOS, IL-1ß, IL-6 and CXCL10 and the levels of nitric oxide were modulated following CTX in an IRF-1-direct- or -indirect-dependent manner, and highlighted the importance of caspase-1 in driving the sterile inflammatory response to CTX. Our data identify IRF-1 as important for the antitumor efficacy of CTX and for the regulation of many immunomodulatory activities of CTX, such as Th1 polarization, Treg depletion and inflammation.
Assuntos
Ciclofosfamida/farmacologia , Inflamassomos/imunologia , Fator Regulador 1 de Interferon/fisiologia , Leucemia Experimental/tratamento farmacológico , Infecções por Retroviridae/tratamento farmacológico , Linfócitos T Reguladores/imunologia , Células Th1/imunologia , Infecções Tumorais por Vírus/tratamento farmacológico , Animais , Antineoplásicos Alquilantes/farmacologia , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Citocinas/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Leucemia Experimental/imunologia , Leucemia Experimental/metabolismo , Leucemia Experimental/patologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Vírus Rauscher/patogenicidade , Infecções por Retroviridae/imunologia , Infecções por Retroviridae/metabolismo , Infecções por Retroviridae/patologia , Células Tumorais Cultivadas , Infecções Tumorais por Vírus/imunologia , Infecções Tumorais por Vírus/metabolismo , Infecções Tumorais por Vírus/patologiaRESUMO
An approach toward elucidation of the mechanisms of action of mammalian leukemia viruses has been made by the generation in tissue culture of recombinant viruses between a potent murine leukemia virus (MuLV), Rauscher-MuLV, and an endogenous xenotropic mouse type-C virus, BALB:virus-2, without known malignant potential. Using a double selection system devised to select against the temperature-sensitive (ts) lesion associated with a mutant of Rauscher-MuLV and the xenotropic host range of BALB:virus-2, recombinant viruses were obtained at frequencies ranging from 0.01 to 0.1%. Recombinant viruses were identified on the basis of the type specific antigenic determinants in the translational products of gag (p15, p12, p30, and p10 proteins), pol (reverse transcriptase), and env (gp70 glycoprotein) genes. By this approach, the partial genetic maps of a large number of recombinants were obtained. The fact that p10 of Rauscher-MuLV ts 25, the mutant utilized, was the only protein uniformly lacking in recombinant viruses, localized the lesion inhibiting gag precursor cleavage in this mutant at the carboxy terminus of its gag gene. The recombinant viruses demonstrated two host range phenotypes as defined by Fv-1 host cell restriction. In each case, NB-tropic recombinants possessed the p30 of BALB:virus-2 p30. Thus, it was possible to assign the site of Fv-1 action at, or closely linked, to the viral p30. The target within the viral genome of a second host restriction was also mapped. A serum factor, previously shown to specifically inactivate xenotropic virus infectivity, was demonstrated to exert its action on the viral env gene product. The system described here allows the generation of specific recombinant genotypes that should be useful in defining those regions of the viral genome involved in leukemogenesis.
Assuntos
Genes Virais , Leucemia Experimental/etiologia , Recombinação Genética , Retroviridae/genética , Infecções Tumorais por Vírus/etiologia , Animais , Antígenos Virais , Técnicas de Cultura , Epitopos , Ligação Genética , Camundongos , Vírus Rauscher/genética , Vírus Rauscher/imunologia , Retroviridae/imunologiaRESUMO
BALB/3T3 cells transformed by the Kirsten sarcoma virus (nonvirus producer BALB/3T3 cells) and mutant cell lines derived therefrom by treatment with bromodeoxyuridine (BrdU) were analyzed for expression of virus-specific RNA using single-stranded DNA transcripts of Rauscher leukemia virus (RLV), a virus activated in one of the cell lines (58-2T), and Ki-SV-specific DNA transcript; the latter transcript after removal of all sequences cross-reactive with RLV RNA. The Rauscher virus DNA detected multiple copies of viral RNA in virus-producing cells ( approximately 2.5 x 10(3)/cell) whether infected with RLV or activated to produce virus with BrdU. Nonproducer (NP) cells and normal BALB cells showed small numbers of RNA genomes (70-250/cell) and only partial saturation of the transcript. The intracellular RNA sedimented at 35S (main peak) with a variable minor peak at 20S with the exception of one mutant cell, M-43-2 (main peak at 26-27S). The 58-2T transcript reacted preferentially in NP cells and their derivatives with biphasic kinetics suggesting the possibility of sequences specific for the original transforming virus. The size of Ki-SV specific sequences were 30S in mutant cells whether or not complete virus was being produced and independent of in vivo transplantability.
Assuntos
Transformação Celular Neoplásica , Gammaretrovirus , Vírus Auxiliares , RNA Viral , Vírus Rauscher , Sarcoma Experimental , Animais , Bromodesoxiuridina/farmacologia , Células Cultivadas , Camundongos , Cultura de VírusRESUMO
Endogenous retroviral gp70 was investigated as a participant in the pathogenesis of a lupus-like disease that spontaneously develops in four kinds of mice (NZB, NZB x W MRL/1, and male BXSB). Sera from these strains contain a heavy form of gp 70 that varies in sedimentation rates from 9S to 19S in sucrose density gradient analysis and appears with the onset of disease and persists throughout its course. Immunologically normal strains of mice do not develop rapidly sedimenting gp70 by 8-10 mo of life. The fact that the heavy gp70 is selectively absorbed with anti-IgG antibodies or with Staphylococcus aureus protein A suggests that it is complexed with antibodies. The incidence and quantities of these gp70 ICs rise with the progression of disease in all strains with lupus. These findings suggest that Ig-complexed heavy gp70 may be involved in the pathogenesis of glomerulonephritis of mice with SLE.
Assuntos
Anticorpos Antivirais , Complexo Antígeno-Anticorpo , Antígenos Virais , Gammaretrovirus/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Proteínas Virais/imunologia , Animais , Feminino , Glicoproteínas/imunologia , Masculino , Camundongos , Camundongos Endogâmicos , Vírus Rauscher/imunologia , Especificidade da EspécieRESUMO
Cytolytic T lymphocytes (CTL) were generated against murine tumors induced by Gross, Friend, or Rauscher leukemia virus (LV) in syngeneic mixed leukocyte-tumor cell cultures. Analogous to the patterns of specificity observed with antibodies to LV-induced cell surface antigens, CTL could be classified into two major groups of specificity. Tumor cells induced by Friend, Moloney, or Rauscher virus and positive for the FMR antigen were killed by syngeneic CTL immune to any one of these three LV; the same CTL, however, were incapable of killing syngeneic tumor cells induced by Gross LV. The converse was true for Gross LV-specific CTL: these CTL were specific for syngeneic tumor cells expressing the Gross virus-associated cell-surface antigen (GCSA), and not the FMR antigen. The H-2 specificities of the two groups of LV-immune CTL were also compared, because in both cases, CTL were restricted in their killing activity to H-2-identical tumor target cells. When CTL from single strains of mice were generated against syngeneic FMR- or GCSA-positive tumor cells, differences were observed with respect both to the requirement for the expression of compatible H-2K or H-2D specificities, and to the intensity of the CTL response in congenic mice of the H-2b, H-2d, and H-2k haplotypes.
Assuntos
Vírus AKR da Leucemia Murina/imunologia , Antígenos Virais , Citotoxicidade Imunológica , Epitopos , Antígenos H-2/genética , Células Matadoras Naturais/imunologia , Animais , Antígenos de Neoplasias , Vírus da Leucemia Murina de Friend/imunologia , Genótipo , Leucemia Experimental/imunologia , Teste de Cultura Mista de Linfócitos , Camundongos , Camundongos Endogâmicos BALB C/imunologia , Camundongos Endogâmicos C57BL/imunologia , Vírus Rauscher/imunologiaRESUMO
The natural immune response in mice to their endogenous type-C viruses involves a complex interaction between cellular and humoral immune mechanisms. The virus-specific immune reactivities are a function of age and appear only subsequent to endogenous virus expression. Cellular immune activity was found to reside in a population of lymphocytes that were characterized as natural killer cells based on their absence of theta surface antigens or immunoglobulin or complement receptors. Cellular and humoral virus-specific immune responses co-occur in the same animal and pretreatment of virus-positive target cells with sera from virus-positive aging mice is capable of partially blocking the cytotoxic activity of reactive lymphocytes. The blocking activity of sera from individual mice increases as a function of age and endogenous virus expression and is highly correlated with the virus-specific complement-dependent cytotoxic activity of these sera. Mouse sera, whether naturally immune or immune as a result of hyperimmunization with type-C virus, exhibit blocking activity that can be removed by absorption with purified type-C virus or purified viral glycoprotein (gp 70) but not by absorption with noninfected syngeneic cells. High-titered and highly specific antisera directed against certain individual R-MuLV structural proteins reveal blocking activity. Monospecific antisera to gp 70 and p 12 exhibited high-titered blocking reactivities which are absorbable by the respective purified proteins. Blocking activity of antisera directed against other viral structural proteins could not be excluded with certainty. These findings raise the possibility that immunity in the mouse to endogenous type-C virus or virus-infected cells involves competition between serum-blocking activity and natural-killer cell activity and further provides a unique model system for studying the mechanism of action of blocking antisera known to have monospecific reactivity against defined and purifiable transplantation antigens.
Assuntos
Citotoxicidade Imunológica , Imunidade Inata , Linfócitos/imunologia , Retroviridae/imunologia , Envelhecimento , Animais , Anticorpos Antivirais , Feminino , Glicoproteínas/imunologia , Imunidade Celular , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Vírus Rauscher/imunologia , Baço/imunologia , Proteínas Virais/imunologiaRESUMO
The viral antigenic determinants recognized in an autogenous immune response in mice against their endogenous C-type virus have been identified by SDS-polyacrylamide gel electrophoresis of immune precipitates between various sera and H(3)-labeled intact or disrupted AKR leukemia virus. Normal B6C3F(1) [(C57BL/6 x C3H/Anf)F(1)] serum reacts with viral envelope antigens having mol wt of approximately 68,000, 43,000, and 17,000. In addition, minor reactions with viral antigens having mol wts of approximately 19,000 and 15,000 are demonstrable. The 68,000 and 43,000 mol wt antigens can be labeled with [(3)H]glucosamine and may correspond to the major viral envelope antigens M(2) and M(1), respectively. The antigens recognized by autogenous immune sera do not differ with respect to age of the animal, nor are they significantly different in sera from various strains of mice (BALB/c, C57BL/6, and C3H/Anf). These results suggest that the age-asociated and strain variations in the autogenous immune response, as determined by radioimmune precipitation assays against intact virus, are due to quantitative and qualitative alterations of antibody levels against common antigens.
Assuntos
Anticorpos Antivirais , Isoanticorpos , Vírus da Leucemia Murina/imunologia , Fatores Etários , Animais , Antígenos Virais/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Feminino , Glucosamina/metabolismo , Soros Imunes , Marcação por Isótopo , Leucina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Testes de Precipitina , Vírus Rauscher/efeitos dos fármacos , Vírus Rauscher/imunologia , Tensoativos/farmacologia , TrítioRESUMO
Nervous system tissues from a number of patients with idiopathic neurological disorders were examined for biochemical evidence of RNA tumor virus infection. RNase-sensitive DNA polymerase activity was found in a cytoplasmic particulate fraction from two patients with Guamanian amyotrophic lateral sclerosis (ALS) but not in brains from two normal U.S. individuals. The buoyant density of the enzyme-containing fraction was 1.16-1.18 g/ml and could be converted to a denser region of the gradient (1.24 g/ml) by treatment with the nonionic surfactant, Sterox. The cation and detergent requirements for the endogenous RNase-sensitive DNA polymerase reaction were determined. The early (5 min) endogenous reverse transcriptase product was analyzed by cesium sulfate gradient centrifugation. RNase- and heat-sensitive RNA-DNA hybrids were detected in the product analysis of two ALS, one Parkinsonism-dementia (PD) brain, and two brains from asymptomatic Chamorros but not in brains from normal U.S. individuals and a number of patients with neuro-psychiatric disorders. The DNA product was a 4.5S heteropolymer that hybridized more extensively to RNA extracted from the enzyme-containing pellet from PD brain as compared to a similar fraction from normal U.S. brain. The DNA product appeared to be unrelated to Rausvher or visna virus 70S RNA as determined by RNA-[-3H]DNA hybridization.
Assuntos
Esclerose Lateral Amiotrófica/enzimologia , Encéfalo/enzimologia , Citoplasma/enzimologia , Doença de Parkinson/enzimologia , DNA Polimerase Dirigida por RNA/análise , Autopsia , Química Encefálica , Fracionamento Celular , Centrifugação com Gradiente de Concentração , DNA , Humanos , Hibridização de Ácido Nucleico , RNA , Vírus Rauscher/análise , Trítio , Vírus Visna-Maedi/análiseRESUMO
Leukemic cells from all human chronic granulocytic leukemia (CGL) and some acute myelomonocytic leukemia (AMML) donors are lysed by rabbit antisera to a purified glycoprotein of Friend murine leukemia virus (FLV gp71) in a microcytotoxicity assay. These antisera are not cytotoxic to cells from patients with acute myelocytic leukemia (AML), acute lymphocytic leukemia (ALL), chronic lymphocytic leukemia (CLL), or to peripheral blood lymphocytes from normal donors. A goat antiserum to gradient purified FLV in addition to reacting with cells from CGL and AMML donors also reacted with cells from AML patients and some ALL donors. However, this antiserum failed to react with cells from CLL patients. Peripheral blood and bone marrow leukocytes prepared from leukemic patients in clinical remission failed to react with antisera to FLV and FLV gp71. Absorption experiments demonstrated that the antigen on CGL cells which is reacting with the antiserum to FLV gp71 is also present on normal human platelets and neutrophils. Similar absorption studies showed that the antigen on AML cells detected by the FLV antiserum is not present on normal leukocytes and platelets and appears to be related to the major internal p30 antigens of mammalian RNA tumor viruses. Another antigenic relationship between oncornaviruses and membrane antigens of human leukemia cells was shown by the ability of FLV antigens to absorb the cytotoxic reactivity of nonhuman primate antisera detecting human leukemia-associated antigens. FLV and FLV gp71 antigens were able to absorb all cytotoxic activity of monkey and chimpanzee antisera to human myeloid leukemia antigens when these antisera were tested with CGL cells. These two approaches to an analysis of cross-reactivity indicate that the antigenic determinant(s) detected by the cytotoxic reactions of the FLV gp71 antiserum with human CGL cells is different from the determinant on FLV gp71 which is responsible for the inhibition of the reactivity of simian antisera with CGL cells. Since the goat and rabbit antisera to FLV and FLV gp71 are able to distinguish AML from CGL cells by direct cytotoxicity testing and absorption, they may be valuable reagents for the serological diagnosis of myeloid leukemia. In addition, since peripheral blood cells from AML and CGL patients in clinical remission were seronegative, the antisera may be valuable as management aids. The data in this report indicates that whatever the mechanism of leukemogenesis is in man, cells from CGL and AML patients possess certain membrane antigens which cross-react with FLV structural components such as p30 and gp71.
Assuntos
Antígenos de Neoplasias , Antígenos Virais , Leucemia/imunologia , Vírus Oncogênicos/imunologia , Membrana Celular/imunologia , Reações Cruzadas , Testes Imunológicos de Citotoxicidade , Epitopos , Vírus da Leucemia Murina de Friend/imunologia , Humanos , Leucemia Linfoide/imunologia , Leucemia Monocítica Aguda/imunologia , Leucemia Mieloide/imunologia , Linfócitos/imunologia , Vírus do Tumor Mamário do Camundongo/imunologia , Vírus Rauscher/imunologia , Especificidade da EspécieRESUMO
A radioimmunoassay specific for a murine leukemia virus structural protein, the gs antigen, detects an antigenic reactivity in normal murine cells in culture and natural tissues. The assay was shown to measure an antigen that is highly related to the virion protein as shown by absorption tests, immunoadsorbent chromatography, and by analysis of linearized dose-response curves. These findings combined with the finding of viral-specific RNA indicate that portions of the viral genome are being expressed with a much greater frequency than previously appreciated.
Assuntos
Antígenos Virais/análise , Rim/imunologia , Vírus da Leucemia Murina/imunologia , Fígado/imunologia , Tecido Linfoide/imunologia , Proteínas Virais/análise , Animais , Linhagem Celular , Células Cultivadas/análise , Cromatografia de Afinidade , Feminino , Humanos , Isótopos de Iodo , Masculino , Camundongos , Camundongos Endogâmicos , Hibridização de Ácido Nucleico , RNA Viral/análise , Radioimunoensaio , Ratos , Vírus Rauscher/imunologia , Retroviridae/imunologia , Timidina , TrítioRESUMO
Spleens from Moloney sarcoma virus (MSV) tumor-bearing C57BL/6N mice contained four times the normal number of mononuclear cells and displayed a markedly elevated "spontaneous" (mitogen-independent) DNA synthesis on a per cell basis. The number of macrophages were increased three-fold while there was a slight reduction in the percentage of T lymphocytes. The phytohemagglutinin (PHA) response on a per cell basis of spleens from tumor-bearing mice was decreased about 90% when compared with normal control mice. The primary in vitro immune response to sheep red blood cells was also suppressed to levels of less than 10% of normals. The PHA response could be restored by purification of MSV spleen cells by rayon adherence columns and by removal of phagocytic cells by an iron/magnet technique. The activity of suppressor cells in MSV spleens was demonstrated in mixtures with syngeneic normal spleen cells where a marked impairment of the PHA response was observed. Spleen cells from tumor-free nude mice and normal spleen cells treated by anti-theta serum plus guinea pig complement (C'), both totally unreactive to PHA, had no such effect. The inhibitor cell in MSV spleens was shown to be insensitive to inactivation by anti-theta plus C', but could be removed by the adherence columns and the iron/magnet technique. These data suggest that this suppressor cell is a cell of the monocyte/macrophage series. Suggestive evidence was also presented that the suppressor cells belong to a proliferating population in MSV spleens. Similar suppressor cells have been previously demonstrated in spleens of mice during a variety of immune responses. Our data show, that a tumor, although stimulating the immune system, nevertheless may be suppressive on certain immune functions through the activation of suppressor cells.
Assuntos
Terapia de Imunossupressão , Linfócitos/imunologia , Vírus da Leucemia Murina de Moloney/imunologia , Sarcoma Experimental/imunologia , Baço/imunologia , Animais , Formação de Anticorpos , Antígenos , Soro Antilinfocitário/farmacologia , Bromodesoxiuridina/farmacologia , Adesão Celular , Células Cultivadas , Radioisótopos de Cromo , Testes Imunológicos de Citotoxicidade , Eritrócitos/imunologia , Técnica de Placa Hemolítica , Ferro , Lectinas/farmacologia , Magnetismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Vírus Rauscher/imunologia , Baço/citologia , Timo/anormalidadesRESUMO
The use of monospecific antisera for the analysis by radioimmunoassay and immunofluorescence study of two major viral proteins, gp69/71 and p30 of murine leukemia virus, that could be of significance in the pathogenesis of immune complex glomerulonephritis of mice, particularly NZB and B/WF(1) hybrid mice, yielded the following conclusions. A remarkably high concentration of viral envelope glycoprotein, gp69/71, was detected in the spleen and serum of New Zealand mice (NZB, NZW, B/WF(1), and W/BF(1)); the concentration in the spleen was 10-fold greater than that found in AKR mice and 30-fold greater than that present in C57BL/6 mice. The gp69/71 was deposited along with bound immunoglobulins, apparently as an immune complex, in the diseased kidneys of mice, and the glomerular site and extent of deposition of gp69/71 was related to the severity of the glomerulonephritis. This study suggests that the pathogenesis of immune complex glomerulonephritis (and vasculitis) in mice is related to the expression of this specific viral envelope glycoprotein and to the host immune response to this protein.
Assuntos
Antígenos Virais , Glomerulonefrite/imunologia , Doenças do Complexo Imune/imunologia , Camundongos Endogâmicos/imunologia , Vírus Rauscher/imunologia , Animais , Anticorpos Antivirais , Reações Antígeno-Anticorpo , Antígenos Virais/análise , Imunofluorescência , Genes , Glomerulonefrite/etiologia , Glicoproteínas/imunologia , Hibridização Genética , Doenças do Complexo Imune/etiologia , Rim/imunologia , Glomérulos Renais/imunologia , Camundongos , Camundongos Endogâmicos NZB , Testes de Precipitina , Radioimunoensaio , Baço/imunologia , Proteínas Virais/imunologiaRESUMO
Small peptides, derived from endogenous proteins bind within the antigen binding groove created by the beta-pleated sheets and alpha helices of the alpha 1 and alpha 2 domains of the class I molecule of the major histocompatibility complex (MHC). However, the precise role of peptide in class I MHC conformation remains unclear. Here, we have shown that, in at least some instances, changes induced in the MHC molecule by the binding of distinct peptides can be identified as specific alterations in serological epitopes expressed on the class I protein. The nature of specific peptides expressed by class I-bearing cells may, therefore, have a dramatic influence on T cell development, self-tolerance, and alloreactivity.
Assuntos
Antígenos de Histocompatibilidade Classe I/química , Complexo Principal de Histocompatibilidade , Peptídeos/química , Conformação Proteica , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais , Sítios de Ligação , Transformação Celular Viral , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Linfoma , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Ovalbumina/química , Ovalbumina/imunologia , Peptídeos/síntese química , Vírus Rauscher/genética , Células Tumorais CultivadasRESUMO
Acute thrombocytopenia and megakaryocyte infection have been investigated during the preleukemic phase of the disease induced by the Rauscher murine leukemia virus (RMuLV) in mice. Injection of RMuLV, either intravenously or intraperitoneally, rapidly induced thrombocytopenia, possibly as a result of direct interaction between platelets and viral particles. The susceptibility to this acute thrombocytopenia was genetically controlled and was inherited as a dominant trait. Murine strains with H-2d or H-2k haplotype, which are susceptible to the induction of leukemia by RMuLV, developed thrombocytopenia, whereas leukemia-resistant H-2b and H-2q strains of mice failed to develop thrombocytopenia. Using B10 H-2-congenic and intra-H-2-recombinant mice, it was shown that the susceptibility to RMuLV-induced thrombocytopenia was controlled by gene(s) in or closely linked to the D region of the H-2 complex. Megakaryocytes may be one of the first sites for the replication of RMuLV. Indeed, among bone marrow cells, only megakaryocytes expressed viral antigens gp70 and p30 during the initial phase of RMuLV infection. In addition, megakaryocytes from infected mice were able to transfer preleukemic thrombocytopenia as well as leukemia in syngeneic mice. The infection of megakaryocytes by RMuLV appears to be genetically controlled in a manner similar to the induction of thrombocytopenia, since only the megakaryocytes from mice developing thrombocytopenia were infected by RMuLV. These results indicate that the gene(s) governing the induction of thrombocytopenia by RMuLV may be the same gene(s) (or closely linked to the gene) that controls the susceptibility to leukemogenesis, and would be consistent with the expression of the gene product, presumably a receptor-like molecule for RMuLV, on platelet and megakaryocyte membranes.
Assuntos
Leucemia Experimental/genética , Megacariócitos/imunologia , Trombocitopenia/genética , Doença Aguda , Animais , Antígenos Virais/análise , Antígenos Virais/genética , Células da Medula Óssea , Suscetibilidade a Doenças , Feminino , Antígenos H-2/genética , Antígenos H-2/imunologia , Cinética , Leucemia Experimental/etiologia , Leucemia Experimental/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Camundongos Endogâmicos DBA , Vírus Rauscher/imunologia , Trombocitopenia/etiologia , Trombocitopenia/imunologia , Proteínas do Envelope Viral , Proteínas Virais/análiseRESUMO
After rapid multiple extractions of mouse plasma virus with ether, the aqueous solution contained viral nucleoids that were infectious when inoculated intracranially into newborn BALB/c mice. The infectivity associated with the ether extract was not neutralized by the specific antibody prepared against the whole virus. No intact virus has been seen in these preparations. Treatment with ether completely removed the virus envelope from the particle and produced an apparently homogeneous preparation of viral nucleoids. After the extractions with ether, leukemogenic activity was inactivated by exposure to ribonuclease. The leukemogenic activity of the many-passaged Rauscher virus that has been propagated in tissue culture and that has low infectivity was also retained, and, in two experiments in which material was inoculated intracranially into mice, this activity appeared to have been enhanced by multiple extractions with ether.
Assuntos
Vírus Rauscher/patogenicidade , Animais , Animais Recém-Nascidos , Técnicas de Cultura , Éteres , Camundongos , Microscopia Eletrônica , Testes de Neutralização , Vírus Rauscher/imunologia , Ribonucleases , VirulênciaRESUMO
Friend, Rauscher, and polycythemic viruses produce a marked erythrocytopoiesis in the spleens of infected mice. The erythrocytopoiesis induced by the Friend and Rauscher viruses can be inhibited in a hypertransfused polycythemic state. Like erythropoietin, the polycythemic virus can initiate erythropoiesis in this state. However, the mechanism by which the polycythemic virus initiates erythropoiesis in this state is not understood. These studies also show similarity of the Friend and Rauscher viruses in their erythropoietic response.
Assuntos
Eritropoese , Vírus da Leucemia Murina de Friend , Policitemia , Vírus Rauscher , Vírus , Animais , Camundongos , Baço/patologia , VirosesRESUMO
Stocks of inurine sarcoma virus show titration patterns ranging from one-to two-hit kinetics. The comparison of various titrations of this virus, both with and without added helper virus, to theoretical model systems composed of defined constituents, suggests the existence of a sarcoma virus that does not need coinfectinig murine leukemia virus to be manifested as a focus-forming unit. The behavior of such nondefective particles is compatible with a postulated leukemia-sarcoma virus hybrid.
Assuntos
Vírus da Leucemia Murina/patogenicidade , Vírus da Leucemia Murina de Moloney/patogenicidade , Sarcoma Experimental , Animais , Técnicas de Cultura , Vírus Defeituosos , Genética Microbiana , Vírus Auxiliares , Cinética , Camundongos , Modelos Biológicos , RNA Viral , Vírus Rauscher , Proteínas ViraisRESUMO
Analysis of the ability of heteroantisera, monoclonal antibodies, and antibodies to synthetic peptides to react with viral glycoproteins deglycosylated with endoglycosidase F revealed that the reactivities of most of the antibodies to these glycoprotein antigens were influenced by the attached carbohydrate moieties. All heteroantisera prepared in rabbits or goats to either fully glycosylated retroviruses or influenza virus were virtually unreactive toward the viral glycoproteins after carbohydrate removal. Analyses with a panel of monoclonal antibodies to purified Rauscher murine leukemia virus gp70 indicated that the reactivity of most of these antibodies improved while the reactivity of others decreased or remain unchanged after carbohydrate removal. Most of the antibodies to synthetic peptide sequences in the influenza virus hemagglutinin also improved in reactivity after carbohydrate removal. These data indicate that carbohydrate side chains on viral glycoproteins influence the immune response to these antigens, and the more native the glycoprotein immunogen, the more dramatic the carbohydrate influence. Thus the immune response to these glycoproteins is not simply a function of the immunogenicity of certain domains over others but rather is a direct measure of carbohydrate influences on the host's perception of the foreign antigen.
Assuntos
Reações Antígeno-Anticorpo , Antígenos Virais/imunologia , Carboidratos/fisiologia , Soros Imunes/imunologia , Proteínas Virais/imunologia , Anticorpos Monoclonais/imunologia , Orthomyxoviridae/imunologia , Vírus Rauscher/imunologiaRESUMO
Fischer rat embryo cells were treated with 3-methylcholanthrene before or after inoculation with Rauscher murine leukemia virus. Transformation was not observed in untreated control cultures, cultures given virus or 3-methyl-cholanthrene alone, or cultures treated first with 3-methylcholanthrene followed by inoculation with the virus after removal of the chemical. Transformation was dependent upon the presence of Rauscher murine leukemia virus at the time of chemical treatment.