Dataset Information

Sanjuan2013 - Evolution of HIV T-cell epitope, control model

ABSTRACT: Sanjuan2013 - Evolution of HIV T-cell epitope, control model Control model in which the virus targets a nonimmune cell type C (e.g., hepatocytes, epithelial cells, etc.), instead of T H cells. This model is described in the article: Immune activation promotes evolutionary conservation of T-cell epitopes in HIV-1. Sanjuán R, Nebot MR, Peris JB, Alcamí J. PLoS Biol. 2013 Apr;11(4):e1001523 Abstract: The immune system should constitute a strong selective pressure promoting viral genetic diversity and evolution. However, HIV shows lower sequence variability at T-cell epitopes than elsewhere in the genome, in contrast with other human RNA viruses. Here, we propose that epitope conservation is a consequence of the particular interactions established between HIV and the immune system. On one hand, epitope recognition triggers an anti-HIV response mediated by cytotoxic T-lymphocytes (CTLs), but on the other hand, activation of CD4(+) helper T lymphocytes (TH cells) promotes HIV replication. Mathematical modeling of these opposite selective forces revealed that selection at the intrapatient level can promote either T-cell epitope conservation or escape. We predict greater conservation for epitopes contributing significantly to total immune activation levels (immunodominance), and when TH cell infection is concomitant to epitope recognition (trans-infection). We suggest that HIV-driven immune activation in the lymph nodes during the chronic stage of the disease may offer a favorable scenario for epitope conservation. Our results also support the view that some pathogens draw benefits from the immune response and suggest that vaccination strategies based on conserved TH epitopes may be counterproductive. This model is hosted on BioModels Database and identified by: MODEL1302180002 . To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models . To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.

SUBMITTER: Rafael Sanjuan

PROVIDER: MODEL1302180002 | BioModels | 2005-01-01

REPOSITORIES: BioModels

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			Action	DRS
	MODEL1302180002?filename=MODEL1302180002-biopax2.owl	Owl
	MODEL1302180002?filename=MODEL1302180002-biopax3.owl	Owl
	MODEL1302180002?filename=MODEL1302180002.m	Other
	MODEL1302180002?filename=MODEL1302180002.pdf	Pdf
	MODEL1302180002?filename=MODEL1302180002.png	Other

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Immune activation promotes evolutionary conservation of T-cell epitopes in HIV-1.

Sanjuán Rafael R Nebot Miguel R MR Peris Joan B JB Alcamí José J

PLoS biology 20130402 4

The immune system should constitute a strong selective pressure promoting viral genetic diversity and evolution. However, HIV shows lower sequence variability at T-cell epitopes than elsewhere in the genome, in contrast with other human RNA viruses. Here, we propose that epitope conservation is a consequence of the particular interactions established between HIV and the immune system. On one hand, epitope recognition triggers an anti-HIV response mediated by cytotoxic T-lymphocytes (CTLs), but o ...[more]

PMID: 23565057

Similar Datasets

Project description:Sanjuan2013 - Evolution of HIV T-cell epitope, immune activation model Model of cellular immune response against HIV. This model is described in the article: Immune activation promotes evolutionary conservation of T-cell epitopes in HIV-1. Sanjuán R, Nebot MR, Peris JB, Alcamí J. PLoS Biol. 2013 Apr;11(4):e1001523 Abstract: The immune system should constitute a strong selective pressure promoting viral genetic diversity and evolution. However, HIV shows lower sequence variability at T-cell epitopes than elsewhere in the genome, in contrast with other human RNA viruses. Here, we propose that epitope conservation is a consequence of the particular interactions established between HIV and the immune system. On one hand, epitope recognition triggers an anti-HIV response mediated by cytotoxic T-lymphocytes (CTLs), but on the other hand, activation of CD4(+) helper T lymphocytes (TH cells) promotes HIV replication. Mathematical modeling of these opposite selective forces revealed that selection at the intrapatient level can promote either T-cell epitope conservation or escape. We predict greater conservation for epitopes contributing significantly to total immune activation levels (immunodominance), and when TH cell infection is concomitant to epitope recognition (trans-infection). We suggest that HIV-driven immune activation in the lymph nodes during the chronic stage of the disease may offer a favorable scenario for epitope conservation. Our results also support the view that some pathogens draw benefits from the immune response and suggest that vaccination strategies based on conserved TH epitopes may be counterproductive. Note from the author: this version of the model is more general that the one described in the paper. This is because: (i) it can consider simultaneously Th-epitope escape mutants, CTL-epitope escape mutants and full T-cell (Th and CTL) escape mutants, by setting the mutation rate of Th and CTL escape mutants to zero. (ii) It allows for back mutations, which were ignored in all the simulations shown in the paper. (iii) It allows for a fitness cost of escape mutants, which was set to zero in the article. (iv) pAPCs can be infected and produce viruses (the rate of viral production for pAPCs was set to zero in the paper). This model is hosted on BioModels Database and identified by: MODEL1302180001 . To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models . To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.

Project description:Macrophages provide an interface between innate and adaptive immunity and are important long-lived reservoirs for Human Immunodeficiency Virus Type-1 (HIV-1). Multiple genetic networks involved in regulating signal transduction cascades and immune responses in macrophages are coordinately modulated by HIV-1 infection. To evaluate complex interrelated processes and to assemble an integrated view of activated signaling networks, a systems biology strategy was applied to genomic and proteomic responses by primary human macrophages over the course of HIV-1 infection. Macrophage responses, including cell cycle, calcium, apoptosis, mitogen-activated protein kinases (MAPK), and cytokines/chemokines, to HIV-1 were temporally regulated, in the absence of cell proliferation. In contrast, Toll-like receptor (TLR) pathways remained unaltered by HIV-1, although TLRs 3, 4, 7, and 8 were expressed and responded to ligand stimulation in macrophages. HIV-1 failed to activate phosphorylation of IRAK-1 or IRF-3, modulate intracellular protein levels of Mx1, an interferon-stimulated gene, or stimulate secretion of TNF, IL-1b, or IL-6. Activation of pathways other than TLR was inadequate to stimulate, via cross-talk mechanisms through molecular hubs, the production of proinflammatory cytokines typical of a TLR response. HIV-1 sensitized macrophage responses to TLR ligands, and the magnitude of viral priming was related to virus replication. HIV-1 induced a primed, proinflammatory state, M1HIV, which increased the responsiveness of macrophages to TLR ligands. HIV-1 might passively evade pattern recognition, actively inhibit or suppress recognition and signaling, or require dynamic interactions between macrophages and other cells, such as lymphocytes or endothelial cells. HIV-1 evasion of TLR recognition and simultaneous priming of macrophages may represent a strategy for viral survival, contribute to immune pathogenesis, and provide important targets for therapeutic approaches. Affymetrix arrays were used to identify genomic macrophage response to HIV during viral spread in culture. Experiment Overall Design: An HIV-1 spreading infection was established in primary human macrophages. RNA was extracted from both viral- and mock-infected macrophages cultures over 7 days and hybridized to Affymetrix HG-U95Av2 GeneChips for analysis.