MHC Class II and HIV pathogenesis: lots of data, few conclusions

Lipman, Marc

doi:10.1046/j.1365-2362.2001.00928.x

Cited by 3 publications

(2 citation statements)

References 10 publications

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“…Indeed, expression of HIV-1 Nef, Vpu and Gag have been shown to alter HLA-DR trafficking [37,38,39,40]. In addition, HLA-DR is preferentially acquired on the viral envelope of budding virions, which enhances virion infectivity and may play a role in bystander apoptosis of T lymphocytes [41,42,43]. Therefore, HLA-DR localization at virus assembly sites is not unexpected.…”

Section: Introductionmentioning

confidence: 99%

Class II Transactivator (CIITA) Enhances Cytoplasmic Processing of HIV-1 Pr55Gag

et al. 2010

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BackgroundThe Pr55gag (Gag) polyprotein of HIV serves as a scaffold for virion assembly and is thus essential for progeny virion budding and maturation. Gag localizes to the plasma membrane (PM) and membranes of late endosomes, allowing for release of infectious virus directly from the cell membrane and/or upon exocytosis. The host factors involved in Gag trafficking to these sites are largely unknown. Upon activation, CD4+ T cells, the primary target of HIV infection, express the class II transcriptional activator (CIITA) and therefore the MHC class II isotype, HLA-DR. Similar to Gag, HLA-DR localizes to the PM and at the membranes of endosomes and specialized vesicular MHC class II compartments (MIICs). In HIV producer cells, transient HLA-DR expression induces intracellular Gag accumulation and impairs virus release.Methodology/Principal FindingsHere we demonstrate that both stable and transient expression of CIITA in HIV producer cells does not induce HLA-DR-associated intracellular retention of Gag, but does increase the infectivity of virions. However, neither of these phenomena is due to recapitulation of the class II antigen presentation pathway or CIITA-mediated transcriptional activation of virus genes. Interestingly, we demonstrate that CIITA, apart from its transcriptional effects, acts cytoplasmically to enhance Pr160gag-pol (Gag-Pol) levels and thereby the viral protease and Gag processing, accounting for the increased infectivity of virions from CIITA-expressing cells.Conclusions/SignificanceThis study demonstrates that CIITA enhances HIV Gag processing, and provides the first evidence of a novel, post-transcriptional, cytoplasmic function for a well-known transactivator.

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Section: Introductionmentioning

confidence: 99%

Class II Transactivator (CIITA) Enhances Cytoplasmic Processing of HIV-1 Pr55Gag

et al. 2010

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“…Indeed, the role of B cells as antigen‐presenting cells in the course of HIV‐1 infection might be increased due to impaired class II expression and antigen uptake in monocytic cells, which can have profound effect on the general structure of immune response in the course of HIV‐1 infection increasing the role of T–B‐cell mutual activation [7–9]. The role of major histocompatibility complex (MHC) class II molecules in HIV‐1 infection remains vague, which underscores the importance of the studies of the HIV‐1‐related processes where MHC class II can play a role [10]. Induction of full‐scale antibody response can serve as an example of these processes for B cells [11].…”

Section: Introductionmentioning

confidence: 99%

Host‐Dependent Serum Specificity to the V3 Domain of HIV‐1

et al. 2004

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The previous studies of anti-HIV-1 humoral immune response have found the stable individual structural bias in the antibody production that reflects the changes in the immune functional network caused by HIV-1. The correlation between antigen structure, in particular the V3 domain of HIV-1, and the serum specificity to the structure remains unclear. To clarify the role of host individual factors in the serum specificity, we used the slightly modified HIV-1 serotyping methodological approach for the sera of the patients infected with HIV-1 with a different level of genetic similarity. Substantial discrepancy between serum specificities and antigen structure was found. Patients infected with HIV-1 carrying similar and identical V3 sequences had significantly different serum specificities. The opposite situation was often observed as well. The results of the study suggest that the influence of the V3 loop structure in the development of humoral immune response to the V3 loop is substantially modified in a patientspecific manner.

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