HIV-Infected Dendritic Cells Present Endogenous MHC Class II-Restricted Antigens to HIV-Specific CD4+ T Cells.
J Immunol
; 197(2): 517-32, 2016 07 15.
Article
em En
| MEDLINE
| ID: mdl-27288536
ABSTRACT
It is widely assumed that CD4(+) T cells recognize antigenic peptides (epitopes) derived solely from incoming, exogenous, viral particles or proteins. However, alternative sources of MHC class II (MHC-II)-restricted Ags have been described, in particular epitopes derived from newly synthesized proteins (so-called endogenous). In this study, we show that HIV-infected dendritic cells (DC) present MHC-II-restricted endogenous viral Ags to HIV-specific (HS) CD4(+) T cells. This endogenous pathway functions independently of the exogenous route for HIV Ag presentation and offers a distinct possibility for the immune system to activate HS CD4(+) T cells. We examined the implication of autophagy, which plays a crucial role in endogenous viral Ag presentation and thymic selection of CD4(+) T cells, in HIV endogenous presentation. We show that infected DC do not use autophagy to process MHC-II-restricted HIV Ags. This is unlikely to correspond to a viral escape from autophagic degradation, as infecting DC with Nef- or Env-deficient HIV strains did not impact HS T cell activation. However, we demonstrate that, in DC, specific targeting of HIV Ags to autophagosomes using a microtubule-associated protein L chain 3 (LC3) fusion protein effectively enhances and broadens HS CD4(+) T cell responses, thus favoring an endogenous MHC-II-restricted presentation. In summary, in DC, multiple endogenous presentation pathways lead to the activation of HS CD4(+) T cell responses. These findings will help in designing novel strategies to activate HS CD4(+) T cells that are required for CTL activation/maintenance and B cell maturation.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Células Dendríticas
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Ativação Linfocitária
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Linfócitos T CD4-Positivos
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Infecções por HIV
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Apresentação de Antígeno
Limite:
Humans
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article