RESUMEN
OBJECTIVE: To evaluate the immunological and virological responses to highly active antiretroviral therapy (HAART) in blood and lymphoid compartments of HIV-1-infected patients at an early stage of infection. DESIGN: An open-label, observational, non-randomized, prospective trial of outpatients attending the Centre of Clinical Investigation in Infectious Diseases, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Switzerland. SUBJECTS: Forty-one antiretroviral-naive HIV-1-infected adults with 400 CD4 T cells/microl or greater and 5000 plasma HIV-1-RNA copies/ml or greater were enrolled, and 32 finished the study. Forty-nine HIV-negative individuals were included as controls. All subjects gave written informed consent. INTERVENTIONS: All patients received abacavir 300 mg by mouth every 12 h and amprenavir 1200 mg by mouth every 12 h for 72 weeks. MAIN OUTCOME MEASURES: The extent of immune reconstitution in blood and lymph nodes after 72 weeks of HAART was evaluated, and compared with immunological measures of 49 HIV-negative subjects. RESULTS: Virus replication was effectively suppressed (-3.5 log10 at week 72). Substantial increments of CD4 T cell count in blood and percentage in lymph nodes were observed over time, and these measures were comparable to HIV-negative subjects by week 24 in blood and by week 48 in lymph nodes. The increase was equally distributed between naive and memory CD4 T cells. Recovery of HIV-specific CD4 responses occurred in 40% of patients. CONCLUSION: The initiation of HAART at an early stage of established HIV infection induces systemic quantitative normalization of CD4 T cells, a partial recovery of HIV-specific CD4 cell responses, and effective and durable suppression of virus replication.
Asunto(s)
Terapia Antirretroviral Altamente Activa , Didesoxinucleósidos/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , VIH-1/fisiología , Sulfonamidas/uso terapéutico , Adolescente , Adulto , Anciano , Recuento de Linfocito CD4 , Relación CD4-CD8 , Carbamatos , Femenino , Furanos , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Inhibidores de la Proteasa del VIH/uso terapéutico , VIH-1/efectos de los fármacos , Humanos , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/patología , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , ARN Viral/sangre , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Carga ViralRESUMEN
Antibodies generated by candidate HIV-1 vaccines in a phase I clinical trial were assessed for neutralizing activity with a panel of eight well-characterized, genetically diverse clade B primary isolates having an R5 phenotype. The vaccines consisted of one of three different recombinant canarypox vectors expressing membrane-anchored HIV-1(MN)gp120 (ALVAC vCP205, vCP1433, and vCP1452) followed by boosting with a soluble gp160 hybrid consisting of MNgp120 and the majority of gp41 from strain IIIB. Serum samples from a subset of volunteers in each arm of the trial, containing moderate to high titers of neutralizing antibodies to HIV-1 MN, were analyzed. Competition assays with peptides revealed that the majority of neutralizing activity was specific for the MN-V3 loop. Despite MN-specific neutralization titers that sometimes exceeded 1:500, no neutralization of primary isolates was detected and, in some cases, mild infection enhancement was observed. In addition, little or no neutralization of the HIV-1 IIIB heterologous T cell line-adapted strain of virus was detected. These results reinforce the notion that monovalent HIV-1 ENV is a poor immunogen for generating cross-reactive neutralizing antibodies.
Asunto(s)
Vacunas contra el SIDA/inmunología , Avipoxvirus/genética , Anticuerpos Anti-VIH/inmunología , Proteína gp120 de Envoltorio del VIH/inmunología , Proteínas gp160 de Envoltorio del VIH/inmunología , Infecciones por VIH/prevención & control , VIH-1/inmunología , Adulto , Secuencia de Aminoácidos , Membrana Celular/metabolismo , Vectores Genéticos , Anticuerpos Anti-VIH/biosíntesis , Anticuerpos Anti-VIH/sangre , Proteína gp120 de Envoltorio del VIH/genética , Proteína gp120 de Envoltorio del VIH/metabolismo , Proteínas gp160 de Envoltorio del VIH/genética , Proteínas gp160 de Envoltorio del VIH/metabolismo , Análisis Heterodúplex , Humanos , Inmunización Secundaria , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Pruebas de Neutralización , Péptidos/química , Péptidos/inmunología , Filogenia , Vacunación , Vacunas Sintéticas/inmunologíaRESUMEN
HIV-specific cytotoxic T lymphocytes (CTL) play a central role in the control of HIV-1 replication during primary infection. It has been hypothesized that the appearance of CTL escape mutants represents an important mechanism by which HIV-1 escapes the host cell-mediated immune response. However, evidences for a direct relationship between CTL responses and emergence of CTL escape mutants are still limited. Here we report detailed longitudinal analysis of DNA sequence variation performed over the entire HIV-1 envelope in two subjects during primary HIV infection. Estimates of the frequencies of synonymous (ds) and non-synonymous (dN) nucleotide substitutions were used to identify regions of the HIV-1 envelope which were subjected to significant levels of selective pressure. These regions were shown to comprise defined epitopes recognized by CTL. Furthermore, dN mutation fixed within these epitopes effectively abolished recognition by the host CTL response. These results provide compelling evidence that the CTL epitope mutations directly resulted from the selective pressure exerted by the virus-specific cytotoxic response.
Asunto(s)
Epítopos de Linfocito T/genética , Variación Genética , Infecciones por VIH/inmunología , VIH-1/genética , VIH-1/inmunología , Epítopos Inmunodominantes/inmunología , Linfocitos T Citotóxicos/inmunología , Células Cultivadas , Epítopos de Linfocito T/inmunología , Proteína gp120 de Envoltorio del VIH/genética , Proteína gp120 de Envoltorio del VIH/inmunología , Proteína gp41 de Envoltorio del VIH/genética , Proteína gp41 de Envoltorio del VIH/inmunología , Infecciones por VIH/sangre , Infecciones por VIH/virología , Humanos , Estudios ProspectivosRESUMEN
A number of pathogenic events occurring immediately after the transmission of HIV lead to the establishment of chronic infection. In fact, despite the detection of vigorous virus-specific immune responses during primary infection, HIV is able to establish chronic infection in most of the cases. This is the result of several virologic and immunologic mechanisms that HIV has evolved to escape and/or to weaken virus-specific immune responses. Lymphoid organs represent the primary anatomic site for the establishment of chronic infection, and if highly active antiretroviral therapy is not initiated in early stage disease, there is a progressive destruction of lymphoid tissue that ultimately leads to the profound immunosuppression typical of AIDS. Therefore, analysis of lymphoid organs is crucial for the correct evaluation of the effectiveness of antiretroviral therapy in HIV infection.
Asunto(s)
Infecciones por VIH/inmunología , Infecciones por VIH/virología , Enfermedad Aguda , Enfermedad Crónica , Infecciones por VIH/terapia , Humanos , Tolerancia Inmunológica , Inmunidad CelularRESUMEN
We show that the fraction of proliferating CD4+ lymphocytes is similar in HIV-infected subjects in the early stage of disease and in HIV-negative subjects, whereas the fraction of proliferating CD8+ lymphocytes is increased 6.8-fold in HIV-infected subjects. After initiation of antiviral therapy, there is a late increase in proliferating CD4+ T cells associated with the restoration of CD4+ T-cell counts. These results provide strong support for the idea of limited CD4+ T-cell renewal in the early stage of HIV infection and indicate that after effective suppression of virus replication, the mechanisms of CD4+ T-cell production are still functional in early HIV infection.
Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Linfocitos T CD4-Positivos/inmunología , Didesoxinucleósidos/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/inmunología , Inhibidores de la Proteasa del VIH/uso terapéutico , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Sulfonamidas/uso terapéutico , Adulto , Anciano , Relación CD4-CD8 , Linfocitos T CD8-positivos/inmunología , Carbamatos , División Celular , Quimioterapia Combinada , Femenino , Furanos , Humanos , Antígeno Ki-67/metabolismo , Ganglios Linfáticos/metabolismo , Masculino , Persona de Mediana EdadRESUMEN
Evolutionary patterns of virus replication and distribution in lymphoid tissue during the early phases of HIV infection have not been delineated. Lymph node (LN) biopsies were excised from patients at different times after the estimated time of primary infection. Within 3 months of the acute viral syndrome, HIV was mostly present in individual virus-expressing cells in LNs; trapping of virions in the follicular dendritic cell (FDC) network was minimal or absent, but was the predominant form of HIV detected in LNs of subjects with chronic infection, either recent (4-20 months after primary infection) or long-term (>2-3 years after primary infection). Plasma viremia was significantly higher in patients during the first 3 months than in those recently infected; however, there were no significant differences in the number of virus-expressing cells per square millimeter of LN tissue in these two groups. Numbers of virus-expressing cells in lymphoid tissue were significantly lower in the subjects with long-term infection than in the other two groups. Therefore, during the transition from primary to chronic HIV infection, the level of HIV replication in lymphoid tissue remains elevated despite the fact that viremia is significantly downregulated. These findings have implications for therapeutic strategies in primary HIV infection and in recent seroconvertors.
Asunto(s)
Infecciones por VIH/virología , VIH/crecimiento & desarrollo , Ganglios Linfáticos/virología , Enfermedad Aguda , Biopsia , Enfermedad Crónica , Células Dendríticas/virología , Progresión de la Enfermedad , Infecciones por VIH/terapia , Humanos , ARN Viral/sangre , Viremia , Replicación ViralRESUMEN
Down-regulation of the initial burst of viremia during primary HIV infection is thought to be mediated predominantly by HIV-specific cytotoxic T lymphocytes, and the appearance of this response is associated with major perturbations of the T cell receptor repertoire. Changes in the T cell receptor repertoire of virus-specific cytotoxic T lymphocytes were analyzed in patients with primary infection to understand the failure of the cellular immune response to control viral spread and replication. This analysis demonstrated that a significant number of HIV-specific T cell clones involved in the primary immune response rapidly disappeared. The disappearance was not the result of mutations in the virus epitopes recognized by these clones. Evidence is provided that phenomena such as high-dose tolerance or clonal exhaustion might be involved in the disappearance of these monoclonally expanded HIV-specific cytotoxic T cell clones. These findings should provide insights into how HIV, and possibly other viruses, elude the host immune response during primary infection.
Asunto(s)
Linfocitos T CD8-positivos/patología , Infecciones por VIH/inmunología , VIH-1 , Secuencia de Aminoácidos , Secuencia de Bases , Linfocitos T CD8-positivos/inmunología , Células Clonales , Antígenos VIH/inmunología , Infecciones por VIH/patología , Humanos , Recuento de Linfocitos , Datos de Secuencia Molecular , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Receptores de Antígenos de Linfocitos T alfa-beta/inmunologíaRESUMEN
Following infection of the host with a virus, the delicate balance between virus replication/spread and the immune response to the virus determines the outcome of infection, i.e., persistence versus elimination of the virus. It is unclear, however, what relative roles immunologic and virologic factors play during primary viral infection in determining the subsequent clinical outcome. By studying a cohort of subjects with primary HIV infection, it has been demonstrated that qualitative differences in the primary immune response to HIV, but not quantitative differences in the initial levels of viremia are associated with different clinical outcomes.
Asunto(s)
Infecciones por VIH/inmunología , Infecciones por VIH/virología , Leucocitos Mononucleares/inmunología , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Viremia , Recuento de Linfocito CD4 , Enfermedad Crónica , Estudios de Cohortes , Progresión de la Enfermedad , Predicción , Humanos , ARN Viral/sangreRESUMEN
Down-regulation of the initial burst of viremia during primary human immunodeficiency virus (HIV) infection is thought to be mediated predominantly by HIV-specific CD8+ cytotoxic T lymphocytes (CTL). This response is associated with major perturbations in the T cell receptor (TCR) repertoire. To investigate the failure of the cellular immune response to adequately control viral spread and replication and to prevent establishment of HIV infection, changes in the TCR repertoire and in the distribution of virus-specific CTL between blood and lymph node were analyzed in three patients with primary infection. By the combined use of clonotype-specific polymerase chain reaction and analysis of the frequency of in vivo activated HIV-specific CTL, it was shown that HIV-specific CTL clones preferentially accumulated in blood as opposed to lymph node. Accumulation of HIV-specific CTL in blood occurred prior to effective down-regulation of virus replication in both blood and lymph node. These findings should provide new insights into how HIV, and possibly other viruses, elude the immune response of the host during primary infection.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Movimiento Celular/inmunología , Infecciones por VIH/inmunología , VIH-1/fisiología , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Subgrupos de Linfocitos T/inmunología , Presentación de Antígeno/inmunología , Antígenos Virales/inmunología , Linfocitos T CD8-positivos/patología , Humanos , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/patología , Subgrupos de Linfocitos T/patología , Replicación Viral/inmunologíaRESUMEN
Initiation of antiretroviral monotherapy early in the course of infection with human immunodeficiency virus may result in a temporary slowing in the rate of disease progression; however, little is known about the virologic effects of early therapy. Virus load was measured in peripheral blood and lymph nodes from 16 antiretroviral-naive patients with a mean CD4 T lymphocyte count of 659 cells/microliter at baseline and after 8 weeks of either no treatment or zidovudine therapy. CD4 T lymphocyte counts and all virologic parameters examined remained unchanged regardless of zidovudine treatment status. Histopathology and virus distribution within lymph nodes remained constant between baseline and week 8 in each patient, indicating that the virologic and histologic parameters examined in a single lymph node are representative of a systemic process. Early antiretroviral monotherapy with zidovudine had no effect on virologic parameters in this group of patients with relatively high CD4 T lymphocyte counts and low measures of virus load at baseline.
Asunto(s)
Antivirales/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , VIH/crecimiento & desarrollo , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Zidovudina/uso terapéutico , Adulto , Secuencia de Bases , Biomarcadores , Recuento de Linfocito CD4 , Cartilla de ADN/química , Femenino , Infecciones por VIH/microbiología , Transcriptasa Inversa del VIH , Humanos , Hibridación in Situ , Ganglios Linfáticos/microbiología , Masculino , Datos de Secuencia Molecular , ADN Polimerasa Dirigida por ARN/metabolismo , Factores de Tiempo , Replicación ViralRESUMEN
In the present study, we have determined the kinetics of constitutive expression of a panel of cytokines [interleukin (IL) 2, IL-4, IL-6, IL-10, interferon gamma (IFN-gamma), and tumor necrosis factor alpha (TNF-alpha)] in sequential peripheral blood mononuclear cell samples from nine individuals with primary human immunodeficiency virus infection. Expression of IL-2 and IL-4 was barely detected in peripheral blood mononuclear cells. However, substantial levels of IL-2 expression were found in mononuclear cells isolated from lymph node. Expression of IL-6 was detected in only three of nine patients, and IL-6 expression was observed when transition from the acute to the chronic phase had already occurred. Expression of IL-10 and TNF-alpha was consistently observed in all patients tested, and levels of both cytokines were either stable or progressively increased over time. Similar to IL-10 and TNF-alpha, IFN-gamma expression was detected in all patients; however, in five of nine patients, IFN-gamma expression peaked very early during primary infection. The early peak in IFN-gamma expression coincided with oligoclonal expansions of CD8+ T cells in five of six patients, and CD8+ T cells mostly accounted for the expression of this cytokine. These results indicate that high levels of expression of proinflammatory cytokines are associated with primary infection and that the cytokine response during this phase of infection is strongly influenced by oligoclonal expansions of CD8+ T cells.
Asunto(s)
Citocinas/biosíntesis , Infecciones por VIH/inmunología , VIH-1 , Linfocitos/inmunología , Células Cultivadas , Regulación Viral de la Expresión Génica , Humanos , Interferón gamma/biosíntesis , Interleucina-10/biosíntesis , Interleucina-2/biosíntesis , Interleucina-4/biosíntesis , Interleucina-6/biosíntesis , Cinética , Ganglios Linfáticos/inmunología , ARN Mensajero/análisis , ARN Mensajero/biosíntesis , Receptores de Antígenos de Linfocitos T alfa-beta , Subgrupos de Linfocitos T/inmunología , Factores de Tiempo , Factor de Necrosis Tumoral alfa/biosíntesisAsunto(s)
Infecciones por VIH/inmunología , Infecciones por VIH/patología , Síndrome de Inmunodeficiencia Adquirida , Animales , ADN Viral/biosíntesis , Células Dendríticas/inmunología , Células Dendríticas/virología , Infecciones por VIH/virología , Humanos , Ganglios Linfáticos/virología , Replicación ViralRESUMEN
Although several immunologic and virologic markers measured in peripheral blood are useful for predicting accelerated progression of human immunodeficiency virus (HIV) disease, their validity for evaluating the response to antiretroviral therapy and their ability to accurately reflect changes in lymphoid organs remain unclear. In the present study, changes in certain virologic markers have been analyzed in peripheral blood and lymphoid tissue during antiretroviral therapy. Sixteen HIV-infected individuals who were receiving antiretroviral therapy with zidovudine for > or = 6 months were randomly assigned either to continue on zidovudine alone or to add didanosine for 8 weeks. Lymph node biopsies were performed at baseline and after 8 weeks. Viral burden (i.e., HIV DNA copies per 10(6) mononuclear cells) and virus replication in mononuclear cells isolated from peripheral blood and lymph node and plasma viremia were determined by semiquantitative polymerase chain reaction assays. Virologic and immunologic markers remained unchanged in peripheral blood and lymph node of patients who continued on zidovudine alone. In contrast, a decrease in virus replication in lymph nodes was observed in four of six patients who added didanosine to their regimen, and this was associated with a decrease in plasma viremia. These results indicate that decreases in plasma viremia detected during antiretroviral therapy reflect downregulation of virus replication in lymphoid tissue.
Asunto(s)
Didanosina/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , VIH-1/aislamiento & purificación , Viremia/tratamiento farmacológico , Zidovudina/uso terapéutico , Adulto , ADN Viral/análisis , Femenino , Infecciones por VIH/sangre , Infecciones por VIH/virología , Humanos , Ganglios Linfáticos/virología , Linfocitos/virología , Masculino , Factores de Tiempo , Viremia/sangre , Viremia/virologíaRESUMEN
BACKGROUND: In a small percentage of persons infected with human immunodeficiency virus type 1 (HIV-1), there is no progression of disease and CD4+ T-cell counts remain stable for many years. Studies of the histopathological, virologic, and immunologic characteristics of these persons may provide insight into the pathogenic mechanisms that lead to HIV disease and the protective mechanisms that prevent progression to overt disease. METHODS AND RESULTS: We studied 15 subjects with long-term nonprogressive HIV infection and 18 subjects with progressive HIV disease. Nonprogressive infection was defined as seven or more years of documented HIV infection, with more than 600 CD4+ T cells per cubic millimeter, no antiretroviral therapy, and no HIV-related disease. Lymph nodes from the subjects with nonprogressive infection had significantly fewer of the hyperplastic features, and none of the involuted features, characteristic of nodes from subjects with progressive disease. Plasma levels of HIV-1 RNA and the viral burden in peripheral-blood mononuclear cells were both significantly lower in the subjects with nonprogressive infection than in those with progressive disease (P = 0.003 and P = 0.015, respectively). HIV could not be isolated from the plasma of the former, who also had significantly higher titers of neutralizing antibodies than the latter. There was viral replication, however, in the subjects with nonprogressive infection, and virus was consistently cultured from mononuclear cells from the lymph nodes. In the lymph nodes virus "trapping" varied with the degree of formation of germinal centers, and few cells expressing virus were found by in situ hybridization. HIV-specific cytotoxic activity was detected in all seven subjects with nonprogressive infection who were tested. CONCLUSIONS: In persons who remain free of disease for many years despite HIV infection the viral load is low, but viral replication persists. Lymph-node architecture and immune function appear to remain intact.
Asunto(s)
Infecciones por VIH/inmunología , VIH-1 , Adulto , Recuento de Linfocito CD4 , Progresión de la Enfermedad , Femenino , Anticuerpos Anti-VIH/sangre , Infecciones por VIH/patología , Infecciones por VIH/virología , Seropositividad para VIH/inmunología , Seropositividad para VIH/patología , Seropositividad para VIH/virología , VIH-1/genética , VIH-1/aislamiento & purificación , VIH-1/ultraestructura , Humanos , Leucocitos Mononucleares/virología , Ganglios Linfáticos/patología , Masculino , Persona de Mediana Edad , ARN Viral/aislamiento & purificación , Viremia/virologíaRESUMEN
Studies of lymphoid tissue from HIV-infected individuals have provided critical insights into the pathogenesis of HIV disease. Systemic dissemination of virus via the lymphatic system occurs at a very early stage after infection. Explosive viral replication within lymphoid tissue ensues, before the development of cell-mediated and humoral immune responses. By the time potent immune responses downregulate viral expression, an immense viral reservoir within lymphoid tissue has already been established. During the stage of dichotomy in viral load between lymph node and peripheral blood, the viral reservoir is maintained by the ability of the follicular dendritic cells (FDC) network to efficiently trap extracellular virions, as well as by immunologic and microenvironmental factors favoring infection of susceptible cells and sequestration of cells already infected. Degeneration of the FDC network and wholesale disruption of lymphoid architecture herald late-stage disease. The dysfunctional lymphoid tissue contributes directly to immunodeficiency and to sharp increases in viral burden and replication as mechanical and immune controls are lost. Studies in HIV-infected long-term nonprogressors indicate that these individuals are able to maintain cell-mediated and humoral immune responses against HIV. These immune responses are responsible, at least in part, for the maintenance of intact lymphoid tissue architecture and the low levels of viral burden and replication detected in these individuals. Studies of the effect of antiretroviral therapy on HIV infection in lymphoid tissue show that decreases in plasma viremia are associated with and most likely are caused by decreases in viral replication within lymphoid tissue. Further understanding of the pathogenic mechanisms within lymphoid tissue will have important implications for early intervention aimed at inducing a long-term nonprogressor state (i.e., preventing disruption of lymphoid tissue integrity), and later intervention aimed at arresting or even reversing damage to the lymphoid system.
Asunto(s)
Infecciones por VIH/patología , Tejido Linfoide/patología , Antivirales/farmacología , Antivirales/uso terapéutico , Progresión de la Enfermedad , VIH/efectos de los fármacos , VIH/fisiología , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/fisiopatología , Humanos , Tejido Linfoide/efectos de los fármacos , Tejido Linfoide/fisiopatología , Replicación ViralRESUMEN
The present study was undertaken to compare the effects of a type-specific (HIV-1 MN) anti-V3 antibody on in vitro human immunodeficiency virus (HIV) infection of peripheral blood mononuclear cells in systems of cell-free versus cell-to-cell transmission of virus. Anti-V3 antibody completely prevented HIV-1 infection when cell-free virus was the sole mechanism of infection. A significant reduction of the neutralizing activity of the anti-V3 antibody was observed when infectivity was dependent on both cell-free and cell-to-cell mechanisms of infection. Furthermore, when cell-to-cell transfer of virions was the primary mechanism of HIV-1 infection, inhibition of HIV-1 infection was not observed. Therefore, a potent neutralizing antibody with a single epitope specificity failed to effectively control dissemination of a persistent HIV-1 infection in a system characterized predominantly by cell-to-cell transfer of virus.