RESUMO
Natural killer (NK) cells bridge the interface between innate and adaptive immunity and are implicated in the control of herpes simplex virus 2 (HSV-2) infection. In subjects infected with human immunodeficiency virus 1 (HIV-1), the critical impact of the innate immune response on disease progression has recently come into focus. Higher numbers of NK cells are associated with lower HIV-1 plasma viraemia. Individuals with the compound genotype of killer cell immunoglobulin-like receptor (KIR) 3DS1 and human leucocyte antigen (HLA)-Bw4-80I, or who have alleles of KIR3DL1 that encode proteins highly expressed on the NK cell surface, have a significant delay in disease progression. We studied the effect of HSV-2 co-infection in HIV-1-infected subjects, and show that HSV-2 co-infection results in a pan-lymphocytosis, with elevated absolute numbers of CD4(+) and CD8(+) T cells, and NK cells. The NK cells in HSV-2 co-infected subjects functioned more efficiently, with an increase in degranulation after in vitro stimulation. The number of NK cells expressing the activating receptors NKp30 and NKp46, and expressing KIR3DL1 or KIR3DS1, was inversely correlated with HIV-1 plasma viral load in subjects mono-infected with HIV-1, but not in subjects co-infected with HSV-2. This suggests that HSV-2 infection mediates changes within the NK cell population that may affect immunity in HIV-1 infection.
Assuntos
Soropositividade para HIV/imunologia , HIV-1/imunologia , Herpes Simples/imunologia , Herpesvirus Humano 2/imunologia , Células Matadoras Naturais/metabolismo , Adulto , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD4-Positivos/virologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/patologia , Linfócitos T CD8-Positivos/virologia , Contagem de Células , Células Cultivadas , Citotoxicidade Imunológica , Progressão da Doença , Feminino , Soropositividade para HIV/complicações , Soropositividade para HIV/patologia , Soropositividade para HIV/fisiopatologia , HIV-1/patogenicidade , Antígenos HLA-B/genética , Antígenos HLA-B/metabolismo , Herpes Simples/complicações , Herpes Simples/patologia , Herpes Simples/fisiopatologia , Herpesvirus Humano 2/patogenicidade , Teste de Histocompatibilidade , Humanos , Imunidade Inata , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/patologia , Células Matadoras Naturais/virologia , Linfocitose , Masculino , Pessoa de Meia-Idade , Receptores KIR3DL1/genética , Receptores KIR3DL1/metabolismo , Receptores KIR3DS1/genética , Receptores KIR3DS1/metabolismoRESUMO
Progressive loss of T cell functionality is a hallmark of chronic infection with human immunodeficiency virus 1 (HIV-1). We have identified a novel population of dysfunctional T cells marked by surface expression of the glycoprotein Tim-3. The frequency of this population was increased in HIV-1-infected individuals to a mean of 49.4 +/- SD 12.9% of CD8(+) T cells expressing Tim-3 in HIV-1-infected chronic progressors versus 28.5 +/- 6.8% in HIV-1-uninfected individuals. Levels of Tim-3 expression on T cells from HIV-1-infected inviduals correlated positively with HIV-1 viral load and CD38 expression and inversely with CD4(+) T cell count. In progressive HIV-1 infection, Tim-3 expression was up-regulated on HIV-1-specific CD8(+) T cells. Tim-3-expressing T cells failed to produce cytokine or proliferate in response to antigen and exhibited impaired Stat5, Erk1/2, and p38 signaling. Blocking the Tim-3 signaling pathway restored proliferation and enhanced cytokine production in HIV-1-specific T cells. Thus, Tim-3 represents a novel target for the therapeutic reversal of HIV-1-associated T cell dysfunction.
Assuntos
Infecções por HIV/imunologia , HIV-1/imunologia , Proteínas de Membrana/imunologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T/imunologia , Animais , Antígenos CD/genética , Antígenos CD/imunologia , Terapia Antirretroviral de Alta Atividade , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/imunologia , Progressão da Doença , MAP Quinases Reguladas por Sinal Extracelular/genética , MAP Quinases Reguladas por Sinal Extracelular/imunologia , Fator de Transcrição GATA3/genética , Fator de Transcrição GATA3/imunologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/patologia , Infecções por HIV/fisiopatologia , HIV-1/patogenicidade , Antígenos HLA , Receptor Celular 2 do Vírus da Hepatite A , Humanos , Proteínas de Membrana/genética , Fenótipo , Receptor de Morte Celular Programada 1 , Fator de Transcrição STAT5/genética , Fator de Transcrição STAT5/imunologia , Transdução de Sinais/imunologia , Proteínas com Domínio T/genética , Proteínas com Domínio T/imunologia , Subpopulações de Linfócitos T/citologia , Linfócitos T/citologia , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/imunologiaRESUMO
BACKGROUND: CD4+CD25high regulatory T (TReg) cells modulate antigen-specific T cell responses, and can suppress anti-viral immunity. In HTLV-1 infection, a selective decrease in the function of TReg cell mediated HTLV-1-tax inhibition of FOXP3 expression has been described. The purpose of this study was to assess the frequency and phenotype of TReg cells in HTLV-1 asymptomatic carriers and in HTLV-1-associated neurological disease (HAM/TSP) patients, and to correlate with measures of T cell activation. RESULTS: We were able to confirm that HTLV-I drives activation, spontaneous IFNgamma production, and proliferation of CD4+ T cells. We also observed a significantly lower proportion of CTLA-4+ TReg cells (CD4+CD25high T cells) in subjects with HAM/TSP patients compared to healthy controls. Ki-67 expression was negatively correlated to the frequency of CTLA-4+ TReg cells in HAM/TSP only, although Ki-67 expression was inversely correlated with the percentage of CD127low TReg cells in healthy control subjects. Finally, the proportion of CD127low TReg cells correlated inversely with HTLV-1 proviral load. CONCLUSION: Taken together, the results suggest that TReg cells may be subverted in HAM/TSP patients, which could explain the marked cellular activation, spontaneous cytokine production, and proliferation of CD4+ T cells, in particular those expressing the CD25highCD127low phenotype. TReg cells represent a potential target for therapeutic intervention for patients with HTLV-1-related neurological diseases.
Assuntos
Infecções por HTLV-I/imunologia , Vírus Linfotrópico T Tipo 1 Humano/imunologia , Paraparesia Espástica Tropical/imunologia , Linfócitos T Reguladores/metabolismo , Adulto , Idoso , Proliferação de Células , Feminino , Regulação da Expressão Gênica/imunologia , Infecções por HTLV-I/complicações , Infecções por HTLV-I/virologia , Humanos , Interferon gama/metabolismo , Subunidade alfa de Receptor de Interleucina-2/biossíntese , Subunidade alfa de Receptor de Interleucina-2/genética , Subunidade alfa de Receptor de Interleucina-7/biossíntese , Subunidade alfa de Receptor de Interleucina-7/genética , Ativação Linfocitária/imunologia , Masculino , Pessoa de Meia-Idade , Paraparesia Espástica Tropical/etiologia , Paraparesia Espástica Tropical/virologia , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/virologia , Carga ViralRESUMO
IL-17 is proinflammatory cytokine secreted by a unique CD4+ T (Th17) cell subset and proposed to play a role in host defense. We hypothesized that Th17 cells are lost in HIV-1 infection. HIV-1-infected children with plasma viremia below 50 copies/ml had IL-17 production, whereas those with detectable viremia had minimal secretion. These results imply viral-mediated destruction or impairment of Th17 cells and argue for complete suppression of viremia for reconstitution of Th17 cells.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/imunologia , Infecções por HIV/virologia , HIV-1/isolamento & purificação , Interleucina-17/biossíntese , Adulto , Células Cultivadas , Criança , Humanos , Carga Viral , Viremia/imunologia , Viremia/virologiaRESUMO
Recent studies indicate that innate immunity in influenza virus infection is an area of substantial importance for our understanding of influenza virus pathogenesis, yet our knowledge of the mechanisms controlling innate immunity remains limited. Further delineation of the roles of NK cells and innate immunity in viral infection may have important implications for the development of improved influenza virus vaccines. In this study, we evaluated the phenotype and function of NK and T lymphocytes, as well as influenza virus-specific immunoglobulin G production, prior to and following vaccination with the routinely administered trivalent influenza virus vaccine. We demonstrate influenza virus antigen-specific innate and adaptive cellular responses and evaluate changes in NK cell receptor expression over time. Our results demonstrate increased innate and adaptive cellular immune responses and show that NK cells are a significant source of gamma interferon (IFN-gamma) following influenza virus vaccination. An increase in the frequency of IFN-gamma-producing NK cells was observed in many subjects postvaccination. The subset distribution with respect to CD56(dim) and CD56(bright) NK cell subsets remained stable, as did the NK cell phenotype with respect to expression of cell surface activating and inhibitory receptors. These results may form the basis for further investigations of the role of NK cells in immunity to influenza.
Assuntos
Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H3N2/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/prevenção & controle , Interferon gama/biossíntese , Células Matadoras Naturais/imunologia , Adulto , Anticorpos Antivirais/biossíntese , Anticorpos Antivirais/imunologia , Antígeno CD56/imunologia , Antígeno CD56/metabolismo , Epitopos , Feminino , Humanos , Imunidade Inata/imunologia , Imunoglobulina G/biossíntese , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Vacinas contra Influenza/uso terapêutico , Influenza Humana/imunologia , Influenza Humana/virologia , Interferon gama/imunologia , Masculino , Pessoa de Meia-Idade , Linfócitos T/imunologia , Linfócitos T/virologiaRESUMO
Human endogenous retroviruses (HERVs) are remnants of ancient infectious agents that have integrated into the human genome. Under normal circumstances, HERVs are functionally defective or controlled by host factors. In HIV-1-infected individuals, intracellular defense mechanisms are compromised. We hypothesized that HIV-1 infection would remove or alter controls on HERV activity. Expression of HERV could potentially stimulate a T cell response to HERV antigens, and in regions of HIV-1/HERV similarity, these T cells could be cross-reactive. We determined that the levels of HERV production in HIV-1-positive individuals exceed those of HIV-1-negative controls. To investigate the impact of HERV activity on specific immunity, we examined T cell responses to HERV peptides in 29 HIV-1-positive and 13 HIV-1-negative study participants. We report T cell responses to peptides derived from regions of HERV detected by ELISPOT analysis in the HIV-1-positive study participants. We show an inverse correlation between anti-HERV T cell responses and HIV-1 plasma viral load. In HIV-1-positive individuals, we demonstrate that HERV-specific T cells are capable of killing cells presenting their cognate peptide. These data indicate that HIV-1 infection leads to HERV expression and stimulation of a HERV-specific CD8+ T cell response. HERV-specific CD8+ T cells have characteristics consistent with an important role in the response to HIV-1 infection: a phenotype similar to that of T cells responding to an effectively controlled virus (cytomegalovirus), an inverse correlation with HIV-1 plasma viral load, and the ability to lyse cells presenting their target peptide. These characteristics suggest that elicitation of anti-HERV-specific immune responses is a novel approach to immunotherapeutic vaccination. As endogenous retroviral sequences are fixed in the human genome, they provide a stable target, and HERV-specific T cells could recognize a cell infected by any HIV-1 viral variant. HERV-specific immunity is an important new avenue for investigation in HIV-1 pathogenesis and vaccine design.
Assuntos
Antígenos Virais/imunologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Retrovirus Endógenos/imunologia , Infecções por HIV/virologia , Estudos de Coortes , Estudos Transversais , Citometria de Fluxo , Infecções por HIV/imunologia , HIV-1 , Humanos , RNA Viral/sangue , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Carga ViralRESUMO
Mycobacterium tuberculosis (MTB) is a leading cause of mortality worldwide from an infectious agent. Natural killer T (NKT) cells recognize mycobacterial antigens and contribute to anti-MTB immunity in mouse models. NKT cells were measured in subjects with pulmonary tuberculosis, MTB-exposed individuals, and healthy controls. NKT cell levels are selectively lower in peripheral blood mononuclear cells from individuals with pulmonary tuberculosis than in both MTB-exposed subjects and healthy control subjects. This apparent loss of NKT cells from the peripheral blood is sustained during the 6 months after the initiation of MTB treatment. These findings indicate that NKT cells may be an important component of antituberculosis immunity.
Assuntos
Antígenos CD1/análise , Células Matadoras Naturais/imunologia , Mycobacterium tuberculosis/imunologia , Tuberculose Pulmonar/imunologia , Adulto , Antígenos CD1d , Estudos de Casos e Controles , Feminino , Citometria de Fluxo , Humanos , Leucócitos Mononucleares/citologia , MasculinoRESUMO
BACKGROUND: Antigen-specific CTL responses are thought to play a central role in containment of HIV-1 infection, but no consistent correlation has been found between the magnitude and/or breadth of response and viral load changes during disease progression. METHODS AND FINDINGS: We undertook a detailed investigation of longitudinal CTL responses and HIV-1 evolution beginning with primary infection in 11 untreated HLA-A2 positive individuals. A subset of patients developed broad responses, which selected for consensus B epitope variants in Gag, Pol, and Nef, suggesting CTL-induced adaptation of HIV-1 at the population level. The patients who developed viral escape mutations and broad autologous CTL responses over time had a significantly higher increase in viral load during the first year of infection compared to those who did not develop viral escape mutations. CONCLUSIONS: A continuous dynamic development of CTL responses was associated with viral escape from temporarily effective immune responses. Our results suggest that broad CTL responses often represent footprints left by viral CTL escape rather than effective immune control, and help explain earlier findings that fail to show an association between breadth of CTL responses and viral load. Our results also demonstrate that CTL pressures help to maintain certain elements of consensus viral sequence, which likely represent viral escape from common HLA-restricted CTL responses. The ability of HIV to evolve to escape CTL responses restricted by a common HLA type highlights the challenges posed to development of an effective CTL-based vaccine.
Assuntos
Antígenos HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Evasão da Resposta Imune , Linfócitos T Citotóxicos/imunologia , Substituição de Aminoácidos , Sequência de Bases , Sequência Consenso , Progressão da Doença , Epitopos/genética , Epitopos/imunologia , Evolução Molecular , Feminino , Antígenos HIV/genética , HIV-1/genética , Antígeno HLA-A2/imunologia , Humanos , Evasão da Resposta Imune/genética , Interferon gama/sangue , Masculino , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico , Fator de Necrose Tumoral alfa/análise , Produtos do Gene gag do Vírus da Imunodeficiência Humana/genética , Produtos do Gene gag do Vírus da Imunodeficiência Humana/imunologia , Produtos do Gene nef do Vírus da Imunodeficiência Humana/genética , Produtos do Gene nef do Vírus da Imunodeficiência Humana/imunologia , Produtos do Gene pol do Vírus da Imunodeficiência Humana/genética , Produtos do Gene pol do Vírus da Imunodeficiência Humana/imunologiaRESUMO
BACKGROUND: In utero transmission of HIV-1 occurs on average in only 3%-15% of HIV-1-exposed neonates born to mothers not on antiretroviral drug therapy. Thus, despite potential exposure, the majority of infants remain uninfected. Weak HIV-1-specific T-cell responses have been detected in children exposed to HIV-1, and potentially contribute to protection against infection. We, and others, have recently shown that the removal of CD4(+) CD25(+) T-regulatory (Treg) cells can reveal strong HIV-1 specific T-cell responses in some HIV-1 infected adults. Here, we hypothesized that Treg cells could suppress HIV-1-specific immune responses in young children. METHODOLOGY/PRINCIPAL FINDINGS: We studied two cohorts of children. The first group included HIV-1-exposed-uninfected (EU) as well as unexposed (UNEX) neonates. The second group comprised HIV-1-infected and HIV-1-EU children. We quantified the frequency of Treg cells, T-cell activation, and cell-mediated immune responses. We detected high levels of CD4(+) CD25(+) CD127(-) Treg cells and low levels of CD4(+) and CD8(+) T cell activation in the cord blood of the EU neonates. We observed HIV-1-specific T cell immune responses in all of the children exposed to the virus. These T-cell responses were not seen in the cord blood of control HIV-1 unexposed neonates. Moreover, the depletion of CD4(+) CD25(+) Treg cells from the cord blood of EU newborns strikingly augmented both CD4(+) and CD8(+) HIV-1-specific immune responses. CONCLUSIONS/SIGNIFICANCE: This study provides new evidence that EU infants can mount strong HIV-1-specific T cell responses, and that in utero CD4(+) CD25(+) T-regulatory cells may be contributing to the lack of vertical transmission by reducing T cell activation.
Assuntos
Infecções por HIV/complicações , Infecções por HIV/imunologia , HIV-1/imunologia , Complicações Infecciosas na Gravidez/imunologia , Linfócitos T Reguladores/imunologia , Adulto , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Estudos de Coortes , Feminino , Sangue Fetal/citologia , Sangue Fetal/imunologia , Infecções por HIV/transmissão , Humanos , Imunidade Celular , Lactente , Recém-Nascido , Transmissão Vertical de Doenças Infecciosas , Ativação Linfocitária , Depleção Linfocítica , Gravidez , Produtos do Gene gag do Vírus da Imunodeficiência Humana/imunologiaRESUMO
The enzyme-linked immunospot (ELISPOT) assay is a highly sensitive and reproducible method for quantifying T cell-mediated immune responses, and has been used to measure antigen-specific responses post-vaccination. While there are several advantages of the ELISPOT assay for use in field settings for large-scale vaccination trials, blood draw volumes are often limited, and the number of antigen-specific responses that can be measured is constrained by the limited cell number. We reasoned that it should be possible to salvage and rescue viable cells from a completed ELISPOT assay post-incubation, to use for further experimentation. Here, we show that cells rescued from an ELISPOT plate after assay are viable, and may be used in a second cytokine-producing assay, in a proliferation assay, or to provide a source of DNA for genetic studies such as human leukocyte antigen (HLA) typing. Rescue of cells after an ELISPOT assay will be particularly useful for increasing sample utility and maximizing data collection from T cell assays in vaccine trials.