Directly infected resting CD4+T cells can produce HIV Gag without spreading infection in a model of HIV latency.
Despite the effectiveness of highly active antiretroviral therapy (HAART) in treating individuals infected with HIV, HAART is not a cure. A latent reservoir, composed mainly of resting CD4+T cells, drives viral rebound once therapy is stopped. Understanding the formation and maintenance of latently infected cells could provide clues to eradicating this reservoir. However, there have been discrepancies regarding the susceptibility of resting cells to HIV infection in vitro and in vivo. As we have previously shown that resting CD4+T cells are susceptible to HIV integration, we asked whether these cells were capable of producing viral proteins and if so, why resting cells were incapable of supporting productive infection. To answer this question, we spinoculated resting CD4+T cells with or without prior stimulation, and measured integration, transcription, and translation of viral proteins. We found that resting cells were capable of producing HIV Gag without supporting spreading infection. This block corresponded with low HIV envelope levels both at the level of protein and RNA and was not an artifact of spinoculation. The defect was reversed upon stimulation with IL-7 or CD3/28 beads. Thus, a population of latent cells can produce viral proteins without resulting in spreading infection. These results have implications for therapies targeting the latent reservoir and suggest that some latent cells could be cleared by a robust immune response.
Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America.
Matthew J
MJ
Pace
Erin H
EH
Graf
Luis M
LM
Agosto
Angela M
AM
Mexas
Frances
F
Male
Troy
T
Brady
Frederic D
FD
Bushman
Una
U
O'Doherty
D018106:CD28 Antigens / Q000378:metabolism; D017252:CD3 Complex / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology*; D002478:Cells, Cultured; D015967:Gene Expression Regulation, Viral; D015658:HIV Infections / Q000276:immunology; D015497:HIV-1 / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D020381:Interleukin-17 / Q000378:metabolism; D015851:Interleukin-7 / Q000276:immunology; D019402:Macrophage Inflammatory Proteins / Q000276:immunology; D017735:Virus Latency; D014779:Virus Replication; D054299:env Gene Products, Human Immunodeficiency Virus / Q000096:biosynthesis*; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000096:biosynthesis*
D018106:CD28 Antigens; D017252:CD3 Complex; D020381:Interleukin-17; D015851:Interleukin-7; D019402:Macrophage Inflammatory Proteins; D054299:env Gene Products, Human Immunodeficiency Virus; D054301:gag Gene Products, Human Immunodeficiency Virus