RESUMO
Characterizing perturbations in the immune response to tuberculosis in HIV can develop insights into the pathogenesis of coinfection. HIV+ TB+ and TB monoinfected (TB+) subjects recruited from clinics in Bamako prior to initiation of TB treatment were evaluated at time-points following initiation of therapy. Flow cytometry assessed CD4+/CD8+ T cell subsets and activation markers CD38/HLA-DR. Antigen specific responses to TB proteins were assessed by intracellular cytokine detection and proliferation. HIV+ TB+ subjects had significantly higher markers of immune activation in the CD4+ and CD8+ T cells compared to TB+ subjects. HIV+ TB+ had lower numbers of TB-specific CD4+ T cells at baseline. Plasma IFNγ levels were similar between HIV+ TB+ and TB+ subjects. No differences were observed in in-vitro proliferative capacity to TB antigens between HIV+ TB+ and TB+ subjects. Subjects with HIV+ TB+ coinfection demonstrate in vivo expansion of TB-specific CD4+ T cells. Immunodeficiency associated with CD4+ T cell depletion may be less significant compared to immunosuppression associated with HIV viremia or untreated TB infection.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Coinfecção/imunologia , Infecções por HIV/imunologia , Tuberculose Pulmonar/imunologia , ADP-Ribosil Ciclase 1/imunologia , Adulto , Fármacos Anti-HIV/uso terapêutico , Antígenos de Bactérias/imunologia , Antituberculosos/uso terapêutico , Proliferação de Células , Coinfecção/tratamento farmacológico , Feminino , Citometria de Fluxo , Infecções por HIV/tratamento farmacológico , Antígenos HLA-DR/imunologia , Humanos , Interferon gama/imunologia , Interleucina-10/imunologia , Interleucina-12/imunologia , Interleucina-13/imunologia , Interleucina-2/imunologia , Ativação Linfocitária/imunologia , Masculino , Tuberculose Pulmonar/tratamento farmacológico , Fator de Necrose Tumoral alfa/imunologiaRESUMO
OBJECTIVES: We compared the use of computational models developed with and without HIV genotype vs. genotyping itself to predict effective regimens for patients experiencing first-line virological failure. METHODS: Two sets of models predicted virological response for 99 three-drug regimens for patients on a failing regimen of two nucleoside/nucleotide reverse transcriptase inhibitors and one nonnucleoside reverse transcriptase inhibitor in the Second-Line study. One set used viral load, CD4 count, genotype, plus treatment history and time to follow-up to make its predictions; the second set did not include genotype. Genotypic sensitivity scores were derived and the ranking of the alternative regimens compared with those of the models. The accuracy of the models and that of genotyping as predictors of the virological responses to second-line regimens were compared. RESULTS: The rankings of alternative regimens by the two sets of models were significantly correlated in 60-69% of cases, and the rankings by the models that use a genotype and genotyping itself were significantly correlated in 60% of cases. The two sets of models identified alternative regimens that were predicted to be effective in 97% and 100% of cases, respectively. The area under the receiver-operating curve was 0.72 and 0.74 for the two sets of models, respectively, and significantly lower at 0.55 for genotyping. CONCLUSIONS: The two sets of models performed comparably well and significantly outperformed genotyping as predictors of response. The models identified alternative regimens predicted to be effective in almost all cases. It is encouraging that models that do not require a genotype were able to predict responses to common second-line therapies in settings where genotyping is unavailable.
Assuntos
Fármacos Anti-HIV/uso terapêutico , Simulação por Computador , Infecções por HIV/tratamento farmacológico , HIV/genética , Adulto , Contagem de Linfócito CD4 , Feminino , Genótipo , HIV/efeitos dos fármacos , Infecções por HIV/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Valor Preditivo dos Testes , Estudos Retrospectivos , Inibidores da Transcriptase Reversa/uso terapêutico , Carga ViralRESUMO
OBJECTIVES: Genotypic HIV drug-resistance testing is typically 60%-65% predictive of response to combination antiretroviral therapy (ART) and is valuable for guiding treatment changes. Genotyping is unavailable in many resource-limited settings (RLSs). We aimed to develop models that can predict response to ART without a genotype and evaluated their potential as a treatment support tool in RLSs. METHODS: Random forest models were trained to predict the probability of response to ART (≤400 copies HIV RNA/mL) using the following data from 14â891 treatment change episodes (TCEs) after virological failure, from well-resourced countries: viral load and CD4 count prior to treatment change, treatment history, drugs in the new regimen, time to follow-up and follow-up viral load. Models were assessed by cross-validation during development, with an independent set of 800 cases from well-resourced countries, plus 231 cases from Southern Africa, 206 from India and 375 from Romania. The area under the receiver operating characteristic curve (AUC) was the main outcome measure. RESULTS: The models achieved an AUC of 0.74-0.81 during cross-validation and 0.76-0.77 with the 800 test TCEs. They achieved AUCs of 0.58-0.65 (Southern Africa), 0.63 (India) and 0.70 (Romania). Models were more accurate for data from the well-resourced countries than for cases from Southern Africa and India (Pâ<â0.001), but not Romania. The models identified alternative, available drug regimens predicted to result in virological response for 94% of virological failures in Southern Africa, 99% of those in India and 93% of those in Romania. CONCLUSIONS: We developed computational models that predict virological response to ART without a genotype with comparable accuracy to genotyping with rule-based interpretation. These models have the potential to help optimize antiretroviral therapy for patients in RLSs where genotyping is not generally available.
Assuntos
Infecções por HIV/tratamento farmacológico , HIV/genética , Adulto , África Subsaariana/epidemiologia , Fármacos Anti-HIV/provisão & distribuição , Fármacos Anti-HIV/uso terapêutico , Simulação por Computador , Bases de Dados Factuais , Feminino , Seguimentos , Infecções por HIV/virologia , Inibidores da Protease de HIV/provisão & distribuição , Inibidores da Protease de HIV/uso terapêutico , Recursos em Saúde , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Valor Preditivo dos Testes , Curva ROC , Inibidores da Transcriptase Reversa/provisão & distribuição , Inibidores da Transcriptase Reversa/uso terapêutico , Romênia/epidemiologia , Falha de Tratamento , Carga ViralRESUMO
BACKGROUND: Used in combination with antiretroviral therapy, subcutaneous recombinant interleukin-2 raises CD4+ cell counts more than does antiretroviral therapy alone. The clinical implication of these increases is not known. METHODS: We conducted two trials: the Subcutaneous Recombinant, Human Interleukin-2 in HIV-Infected Patients with Low CD4+ Counts under Active Antiretroviral Therapy (SILCAAT) study and the Evaluation of Subcutaneous Proleukin in a Randomized International Trial (ESPRIT). In each, patients infected with the human immunodeficiency virus (HIV) who had CD4+ cell counts of either 50 to 299 per cubic millimeter (SILCAAT) or 300 or more per cubic millimeter (ESPRIT) were randomly assigned to receive interleukin-2 plus antiretroviral therapy or antiretroviral therapy alone. The interleukin-2 regimen consisted of cycles of 5 consecutive days each, administered at 8-week intervals. The SILCAAT study involved six cycles and a dose of 4.5 million IU of interleukin-2 twice daily; ESPRIT involved three cycles and a dose of 7.5 million IU twice daily. Additional cycles were recommended to maintain the CD4+ cell count above predefined target levels. The primary end point of both studies was opportunistic disease or death from any cause. RESULTS: In the SILCAAT study, 1695 patients (849 receiving interleukin-2 plus antiretroviral therapy and 846 receiving antiretroviral therapy alone) who had a median CD4+ cell count of 202 cells per cubic millimeter were enrolled; in ESPRIT, 4111 patients (2071 receiving interleukin-2 plus antiretroviral therapy and 2040 receiving antiretroviral therapy alone) who had a median CD4+ cell count of 457 cells per cubic millimeter were enrolled. Over a median follow-up period of 7 to 8 years, the CD4+ cell count was higher in the interleukin-2 group than in the group receiving antiretroviral therapy alone--by 53 and 159 cells per cubic millimeter, on average, in the SILCAAT study and ESPRIT, respectively. Hazard ratios for opportunistic disease or death from any cause with interleukin-2 plus antiretroviral therapy (vs. antiretroviral therapy alone) were 0.91 (95% confidence interval [CI], 0.70 to 1.18; P=0.47) in the SILCAAT study and 0.94 (95% CI, 0.75 to 1.16; P=0.55) in ESPRIT. The hazard ratios for death from any cause and for grade 4 clinical events were 1.06 (P=0.73) and 1.10 (P=0.35), respectively, in the SILCAAT study and 0.90 (P=0.42) and 1.23 (P=0.003), respectively, in ESPRIT. CONCLUSIONS: Despite a substantial and sustained increase in the CD4+ cell count, as compared with antiretroviral therapy alone, interleukin-2 plus antiretroviral therapy yielded no clinical benefit in either study. (ClinicalTrials.gov numbers, NCT00004978 [ESPRIT] and NCT00013611 [SILCAAT study].)
Assuntos
Antirretrovirais/uso terapêutico , Infecções por HIV/tratamento farmacológico , Interleucina-2/uso terapêutico , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Adulto , Terapia Antirretroviral de Alta Atividade , Contagem de Linfócito CD4 , Quimioterapia Combinada , Feminino , Seguimentos , HIV/genética , HIV/isolamento & purificação , Infecções por HIV/mortalidade , Infecções por HIV/virologia , Humanos , Injeções Subcutâneas , Interleucina-2/administração & dosagem , Interleucina-2/análogos & derivados , Masculino , RNA Viral/sangue , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/uso terapêuticoRESUMO
Changes in CD4+ T-cell surface marker phenotype and antigen receptor (TCR) repertoire were examined during the course of HIV infection and following therapy. A preferential decline in naive CD4+ T cells was noted as disease progressed. Following protease inhibitor therapy, naive CD4+ T cells increased only if they were present before initiation of therapy. Disruptions of the CD4+ TCR repertoire were most prevalent in patients with the lowest CD4+ T-cell counts. Antiviral or IL-12 therapy-induced increases in CD4+ T-cell counts led to only minor changes in previously disrupted repertoires. Thus, CD4+ T-cell death mediated by HIV-1 infection may result in a preferential decline in the number of naive CD4+ T cells and disruptions of the CD4+ T-cell repertoire that are not immediately corrected by antiviral or immune-based therapies.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/imunologia , Inibidores da Protease de HIV/uso terapêutico , Indinavir/uso terapêutico , Interleucina-2/uso terapêutico , Progressão da Doença , Infecções por HIV/tratamento farmacológico , Humanos , Antígenos Comuns de Leucócito/sangue , Fenótipo , RNA Mensageiro/sangue , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Gêmeos MonozigóticosRESUMO
The size of the pool of resting CD4+ T cells containing replication-competent HIV in the blood of patients receiving intermittent interleukin (IL)-2 plus highly active anti-retroviral therapy (HAART) was significantly lower than that of patients receiving HAART alone. Virus could not be isolated from the peripheral blood CD4+ T cells in three patients receiving IL-2 plus HAART, despite the fact that large numbers of resting CD4+ T cells were cultured. Lymph node biopsies were done in two of these three patients and virus could not be isolated. These results indicate that the intermittent administration of IL-2 with continuous HAART may lead to a substantial reduction in the pool of resting CD4+ T cells that contain replication-competent HIV.
Assuntos
Fármacos Anti-HIV/uso terapêutico , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/virologia , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Interleucina-2/uso terapêutico , Estudos Transversais , Inibidores da Protease de HIV/uso terapêutico , HIV-1/patogenicidade , Humanos , Interleucina-2/farmacologia , Linfonodos/virologia , Contagem de Linfócitos/efeitos dos fármacos , RNA Viral/sangue , Replicação Viral/efeitos dos fármacosRESUMO
The CD4+ T-cell pool in HIV-infected patients is in a constant state of flux as CD4+ T cells are infected and destroyed by HIV and new cells take their place. To study T-cell survival, we adoptively transferred peripheral blood lymphocytes transduced with the neomycin phosphotransferase gene between syngeneic twin pairs discordant for HIV infection. A stable fraction of marked CD4+ T cells persisted in the circulation for four to eighteen weeks after transfer in all patients. After this time there was a precipitous decline in marked cells in three of the patients. At approximately six months, marked cells were in lymphoid tissues in proportions comparable to those found in peripheral blood. In two patients, the proportion of total signal for the transgene (found by PCR analysis) in the CD4/CD45RA+ T-cell population relative to the CD4/CD45RO+ population increased in the weeks after cell infusion. These findings indicate that genetically-marked CD4+ T cells persist in vivo for weeks to months and that the CD4+ T-cell pool in adults is maintained mostly by the division of mature T cells rather than by differentiation of prethymic stem cells. Thus, after elements of the T-cell repertoire are lost through HIV infection, they may be difficult to replace.
Assuntos
Linfócitos T CD4-Positivos/fisiologia , Infecções por HIV/imunologia , Linfócitos T/fisiologia , Adulto , Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/fisiopatologia , Humanos , Antígenos Comuns de Leucócito/imunologia , Leucopoese , Masculino , Fosfotransferases/genética , Fosfotransferases/metabolismo , RegeneraçãoRESUMO
A highly specific and reproducible antigen-induced, antigen-specific culture and assay system for antibody production by human peripheral blood B lymphocytes has been developed. The system is clearly T cell and monocyte dependent and is independent of exogenous mitogens. The major factors in our ability to trigger specific antibody production with antigen alone have been the use of extremely low concentrations of antigen in vitro (doses several orders of magnitude below those inducing a peak blastogenic response), careful attention to in vitro cell density and culture vessel geometry, and appreciation of the kinetics of the circulating antigen-inducible B cell repertoire. A dichotomy and overlap between antigen-induced, antigen-specific and antigen-induced, polyclonal responses was observed in the study of doubly immunized individuals. Whereas antibody responses highly specific for the antigen in culture were observed under one set of culture conditions (flat-bottomed vessels, 1.5 x 10(6) cells), switching to another culture system (round-bottomed vessels, 5 x 10(5) cells) resulted in polyclonal responses to antigen. Despite these culture condition-related differences in the induction of antibody synthesis, the suppression of specific antibody production that occurred at high concentrations of antigen was specific only for the antigen in culture. The capability to easily and reproducibly look at truly antigen-induced, antigen specific antibody production should be a major tool in furthering the understanding of human B cell activation and immunoregulation.
Assuntos
Formação de Anticorpos , Antígenos , Epitopos , Ativação Linfocitária , Adolescente , Adulto , Linfócitos B/imunologia , Separação Celular , Hemocianinas/imunologia , Humanos , Imunoglobulina M/biossíntese , Cinética , Monócitos , Mitógenos de Phytolacca americana/farmacologiaRESUMO
The success of long-term culture of normal human and murine B cells has been hampered by the limited availability of soluble factors capable of maintaining proliferation of activated B lymphocytes. Previous experiments using various culture-derived supernatants in a human system were unable to separate the activities of B cell growth factor (BCGF) and interleukin 2 (IL-2) by immunochemical means. Thus, purified factors with BCGF activity in the absence of IL-2 activity have not been available for study. In the present study, normal human peripheral blood T cells were fused with the hypoxanthine/aminopterin/thymidine-sensitive human T-leukemic cell line, CEM-6. Supernatants from the resulting hybrid cells were tested for the ability to maintain proliferation of normal human B cells in a recently described assay system for human BCGF. Hybrids demonstrating BCGF activity were cloned by limiting dilution. One hybrid clone, 2B11, continued to support proliferation of B cells in both long-term cultures and 6-d assays at a level significantly above that seen with conventionally produced growth factors. No IL-2 activity was found in the supernatant from hybrid 2B11. The hybridoma supernatant was fractionated by gel filtration, and maximum proliferation of B cells was supported by the 18-20,000 mol wt protein fraction. Thus, a human T-T cell hybridoma that has BCGF activity in the absence of any demonstrable IL-2 activity has been developed. Human T-T cell hybridomas secreting discrete immunoregulatory factors should prove to be powerful tools in dissecting the mechanisms of immunoregulation of human lymphocyte function.
Assuntos
Substâncias de Crescimento/metabolismo , Hibridomas/imunologia , Linfócitos T/imunologia , Linfócitos B/citologia , Divisão Celular , Células Cultivadas , Humanos , Interleucina-4RESUMO
A human IgMk monoclonal antibody, 2F7, of predetermined specificity, has been produced by the fusion of human peripheral blood lymphocytes with the nonsecreting mouse myeloma line SP-1. The heterohybridoma has remained stable for over 8 mo, with culture supernatants containing up to 30 micrograms/ml of specific IgM. The antibody has been shown to be capable of inducing a blastogenic response in the absence of antigen in the peripheral blood lymphocytes of normal subjects immune to the antigen. The ability to choose an antigen, immunize a human subject to that antigen, and then use the peripheral blood lymphocytes from that subject to produce antigen-specific human monoclonal antibodies should be of great value in a wide variety of investigative, diagnostic, and therapeutic endeavors.U
Assuntos
Anticorpos Monoclonais/imunologia , Linfócitos B/imunologia , Hemocianinas/imunologia , Hibridomas/metabolismo , Animais , Anticorpos Monoclonais/biossíntese , Células Produtoras de Anticorpos/imunologia , Humanos , Hibridomas/imunologia , Camundongos , Camundongos Endogâmicos BALB CRESUMO
To address the possible role of replicative senescence in human immunodeficiency virus (HIV) infection, telomere length, telomerase activity, and in vitro replicative capacity were assessed in peripheral blood T cells from HIV+ and HIV- donors. Genetic and age-specific effects on these parameters were controlled by studying HIV-discordant pairs of monozygotic twins. Telomere terminal restriction fragment (TRF) lengths from CD4+ T cells of HIV+ donors were significantly greater than those from HIV- twins. In contrast, telomere lengths in CD8+ T cells from HIV+ donors were shorter than in HIV- donors. The in vitro replicative capacity of CD4+ cells from HIV+ donors was equivalent to that of HIV- donors in response to stimulation through T cell receptor CD3 and CD28. Little or no telomerase activity was detected in freshly isolated CD4+ or CD8+ lymphocytes from HIV+ or HIV- donors, but was induced by in vitro stimulation of both HIV+ and HIV- donor cells. These results suggest that HIV infection is associated with alterations in the population dynamics of both CD4+ and CD8+ T cells, but fail to provide evidence for clonal exhaustion or replicative senescence as a mechanism underlying the decline in CD4+ T cells of HIV-infected donors.
Assuntos
Infecções por HIV/imunologia , Subpopulações de Linfócitos T/imunologia , Telomerase/análise , Telômero/ultraestrutura , Gêmeos Monozigóticos , Adulto , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Células Cultivadas , Senescência Celular , Infecções por HIV/genética , Infecções por HIV/patologia , Humanos , Ativação Linfocitária , Pessoa de Meia-Idade , Subpopulações de Linfócitos T/citologiaRESUMO
Monocytes were maintained in tissue culture for greater than 3 mo in media supplemented with rCSF-1. These cultures provided susceptible target cells for isolation and propagation of virus from PBMC of HIV-infected patients. HIV isolated into monocytes readily infected other rCSF-1-treated monocytes but only inefficiently infected PHA-stimulated lymphoblasts. Similarly, laboratory HIV strains passaged in T cell lines or virus isolated from patients' leukocytes into PHA-stimulated lymphoblasts inefficiently infected rCSF-1-treated monocytes. Persistent, low-level virion production was detected in macrophage culture fluids by reverse transcriptase activity or HIV antigen capture through 6-7 wk. Marked changes in cell morphology with cell death, syncytia, and giant cell formation were observed in monocyte cultures 2 wk after infection, but at 4-6 wk, all cells appeared morphologically normal. However, the frequency of infected cells in these cultures at 6 wk was 60-90% as quantified by in situ hybridization with HIV RNA probes or by immunofluorescence with AIDS patients' sera. Ultrastructural analysis by EM also showed a high frequency of infected cells; virtually all HIV budded into and accumulated within cytoplasmic vacuoles and virus particles were only infrequently associated with the plasma membrane. Retention of virus within macrophages and the macrophage tropism of HIV variants may explain mechanisms of both virus persistence and dissemination during disease.
Assuntos
Fatores Estimuladores de Colônias/farmacologia , HIV/isolamento & purificação , Leucócitos Mononucleares , Cultura de Vírus/métodos , Células Cultivadas , Efeito Citopatogênico Viral , DNA Viral/análise , Soropositividade para HIV/patologia , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/ultraestrutura , Linfócitos/microbiologia , Macrófagos/efeitos dos fármacos , Macrófagos/microbiologia , Provírus/análise , Proteínas Recombinantes/farmacologiaRESUMO
We examined the effects of human immunodeficiency virus infection on the turnover of CD4 and CD8 T lymphocytes in 17 HIV-infected patients by 30 min in vivo pulse labeling with bromodeoxyuridine (BrdU). The percentage of labeled CD4 and CD8 T lymphocytes was initially higher in lymph nodes than in blood. Labeled cells equilibrated between the two compartments within 24 h. Based on mathematical modeling of the dynamics of BrdU-labeled cells in the blood, we identified rapidly and slowly proliferating subpopulations of CD4 and CD8 T lymphocytes. The percentage, but not the decay rate, of labeled CD4 or CD8 cells in the rapidly proliferating pool correlated significantly with plasma HIV RNA levels for both CD4 (r = 0.77, P < 0.001) and CD8 (r = 0.81, P < 0.001) T cells. In six patients there was a geometric mean decrease of greater than 2 logs in HIV levels within 2 to 6 mo after the initiation of highly active antiretroviral therapy; this was associated with a significant decrease in the percentage (but not the decay rate) of labeled cells in the rapidly proliferating pool for both CD4 (P = 0.03) and CD8 (P < 0.001) T lymphocytes. Neither plasma viral levels nor therapy had an effect on the decay rate constants or the percentage of labeled cells in the slowly proliferating pool. Monocyte production was inversely related to viral load (r = -0.56, P = 0.003) and increased with therapy (P = 0.01). These findings demonstrate that HIV does not impair CD4 T cell production but does increase CD4 and CD8 lymphocyte proliferation and death by inducing entry into a rapidly proliferating subpopulation of cells.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/virologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Infecções por HIV/imunologia , HIV-1/fisiologia , Adulto , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/patologia , Divisão Celular/imunologia , Feminino , Infecções por HIV/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Replicação Viral/imunologiaRESUMO
When B lymphocytes from normal human peripheral blood were incubated for 1 hour with the retrovirus that causes the acquired immune deficiency syndrome (AIDS), the B cells showed marked proliferation and differentiation. Proliferative responses to the virus peaked on day 4 and appeared to be independent of accessory cells. This finding was repeated with three separate viral isolates, one of which was from a patient from Zaire. The magnitude of the observed responses was comparable to that seen with standard polyclonal B-cell activators. This phenomenon may be at least partially responsible for the polyclonal B-cell activation seen in patients with AIDS.
Assuntos
Síndrome da Imunodeficiência Adquirida/imunologia , Linfócitos B/imunologia , Deltaretrovirus/imunologia , Diferenciação Celular , Humanos , Imunoglobulinas/metabolismo , Técnicas In Vitro , Ativação Linfocitária , Receptores Virais/fisiologiaRESUMO
Protein tyrosine phosphorylation is a common mechanism of signaling in pathways that regulate T cell receptor-mediated cell activation, cell proliferation, and the cell cycle. Because human immunodeficiency virus (HIV) is though to affect normal cell signaling, tyrosine phosphorylation may be associated with HIV cytopathicity. In both HIV-infected cells and transfected cells that stably express HIV envelope glycoproteins undergoing HIVgp41-induced cell fusion, a 30-kilodalton protein was phosphorylated on tyrosine with kinetics similar to those of syncytium formation and cell death. When tyrosine phosphorylation was inhibited by the protein tyrosine kinase inhibitor herbimycin A, envelope-mediated syncytium formation was coordinately reduced. These studies show that specific intracellular signals, which apparently participate in cytopathicity, are generated by HIV and suggest strategies by which the fusion process might be interrupted.
Assuntos
Efeito Citopatogênico Viral/fisiologia , HIV-1/fisiologia , Fosfoproteínas/metabolismo , Transdução de Sinais/fisiologia , Linfócitos T/fisiologia , Tirosina/metabolismo , Benzoquinonas , Antígenos CD4/fisiologia , Linhagem Celular , Proteína gp41 do Envelope de HIV/genética , Proteína gp41 do Envelope de HIV/fisiologia , Humanos , Lactamas Macrocíclicas , Fosforilação , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Quinonas/farmacologia , Receptores de Antígenos de Linfócitos T/fisiologia , Rifabutina/análogos & derivados , Linfócitos T/microbiologia , Transfecção , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/fisiologiaRESUMO
Human immunodeficiency virus type 1 (HIV-1) selectively infects cells expressing the CD4 molecule, resulting in substantial quantitative and qualitative defects in CD4+ T lymphocyte function in patients with acquired immunodeficiency syndrome (AIDS). However, only a very small number of cells in the peripheral blood of HIV-1-infected individuals are expressing virus at any given time. Previous studies have demonstrated that in vitro infection of CD4+ T cells with HIV-1 results in downregulation of CD4 expression such that CD4 protein is no longer detectable on the surface of the infected cells. In the present study, highly purified subpopulations of peripheral blood mononuclear cells (PBMCs) from AIDS patients were obtained and purified by fluorescence-automated cell sorting. They were examined with the methodologies of virus isolation by limiting dilution analysis, in situ hybridization, immunofluorescence, and gene amplification. Within PBMCs, HIV-1 was expressed in vivo predominantly in the T cell subpopulation which, in contrast to the in vitro observations, continued to express CD4. The precursor frequency of these HIV-1-expressing cells was about 1/1000 CD4+ T cells. The CD4+ T cell population contained HIV-1 DNA in all HIV-1-infected individuals studied and the frequency in AIDS patients was at least 1/100 cells. This high level of infection may be the primary cause for the progressive decline in number and function of CD4+ T cells in patients with AIDS.
Assuntos
Síndrome da Imunodeficiência Adquirida/imunologia , Antígenos de Diferenciação de Linfócitos T/imunologia , HIV-1/fisiologia , Linfócitos T/microbiologia , Síndrome da Imunodeficiência Adquirida/microbiologia , Separação Celular , DNA Viral/análise , Citometria de Fluxo , Imunofluorescência , Amplificação de Genes , HIV-1/genética , Humanos , Hibridização de Ácido Nucleico , RNA Viral/análise , Linfócitos T/imunologiaRESUMO
Two of three chimpanzees given plasma from patients with acquired immune deficiency syndrome (AIDS) or pre-AIDS showed serum antibodies to type III human T-cell leukemia virus (HTLV-III) 10 to 12 weeks after transfusion. One animal also developed lymphadenopathy, transient depression of the ratio of T4 to T8 lymphocytes, and impaired blastogenic responses. No opportunistic infections occurred. Adenopathy persisted for 32 weeks, and antibody to HTLV-III persisted for at least 48 weeks. This transmission of HTLV-III by lymphocyte-poor plasma confirms the potential risk of such plasma or plasma derivatives to recipients. The susceptibility of the chimpanzee to HTLV-III infection and the ability to simulate the human lymphadenopathy syndrome in this animal makes it a valuable model for further study of AIDS.
Assuntos
Síndrome da Imunodeficiência Adquirida/transmissão , Deltaretrovirus , Modelos Animais de Doenças , Pan troglodytes , Síndrome da Imunodeficiência Adquirida/sangue , Síndrome da Imunodeficiência Adquirida/patologia , Animais , Anticorpos Antivirais/imunologia , Deltaretrovirus/imunologia , Humanos , Contagem de Leucócitos , Linfonodos/patologia , Pan troglodytes/microbiologia , Linfócitos TRESUMO
Treatment of SIV-infected rhesus macaques with short-term antiretroviral therapy (ART) and partially overlapping infusions of antibody to integrin α4ß7 was reported to induce durable posttreatment viral suppression. In an attempt to replicate those observations, we treated macaques infected with the same virus and with the same ART and monoclonal antibody (mAb) regimens (anti-α4ß7 versus control mAb). Sequencing demonstrated that the virus used was actually SIVmac239-nef-stop, not wild-type SIVmac239. A positive correlation was found at 2 weeks after infection between the frequency of repair of attenuated Nef-STOP virus to pathogenic Nef-OPEN and plasma SIV RNA levels. Levels of plasma viremia before the first antibody infusion and preinfection levels of α4ß7 hi CD4+ T cells, but not treatment with antibody to α4ß7 , correlated with levels of viral replication upon discontinuation of all treatments. Follow-up plasma viremia, peripheral blood CD4+ T cell counts, and lymph node and rectal tissue viral load were not significantly different between anti-α4ß7 and control mAb groups.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Infecções por HIV/terapia , Integrina alfa4/imunologia , Cadeias beta de Integrinas/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/terapia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/imunologia , Animais , Antirretrovirais/uso terapêutico , Contagem de Linfócito CD4 , Linfócitos T CD4-Positivos/imunologia , Códon de Terminação , Linfonodos/virologia , Macaca mulatta , RNA Viral/sangue , Reto/virologia , Síndrome de Imunodeficiência Adquirida dos Símios/sangue , Síndrome de Imunodeficiência Adquirida dos Símios/tratamento farmacológico , Vírus da Imunodeficiência Símia/fisiologia , Carga Viral , Proteínas Virais Reguladoras e Acessórias/genética , Proteínas Virais Reguladoras e Acessórias/imunologia , Viremia/sangue , Viremia/imunologia , Viremia/terapia , Viremia/virologia , Replicação ViralRESUMO
We have recently noted marked differences between the in vitro responses of human B lymphocytes to stimulation with soluble antigens vs. stimulation with mitogens. In the present study, these differences were analyzed in terms of the precursor frequencies for the T cells and B cells involved and in terms of the radiation sensitivity of the T cells providing help in the two systems. Marked differences were found between antigen-induced and mitogen-induced systems with regard to T cell precursor frequencies and radiation sensitivity. In contrast, the precursor frequencies for the B cells involved in the two systems were approximately the same. In addition, having developed a system for the study of human antigen-specific B cell responses, we were interested in delineating the nature of the allogeneic effects that might be operative in this system. Marked allogeneic effects, both positive and negative, were noted in this system and will need to be taken into account in any studies that try to address the question of the genetic restriction, if any, that exists in human antigen-specific T cell-B cell collaboration. Appreciation of the marked differences between the antigen-specific and mitogen-induced activation and immunoregulation of human B cell responses will be of importance in understanding the relationship between specificity and nonspecificity of antibody production in normal and disease states.