Quantification of HIV-specific CD8 T cells by in vitro stimulation with inactivated viral particles.
OBJECTIVE
HIV-specific CD8 T cells play a central role in the immune control of virus replication. To further understand the role of CD8 T cells in clinical settings, there is a need for a diagnostic assay that quantifies HIV-specific CD8 T cells in all HIV-infected individuals.


METHODS
and methods: The CD8VIR (CD8 T cell-mediated virus-specific immune response) assay was designed to mimic viral load rebound by adding replication defective HIV particles to peripheral blood mononuclear cells. Antigen presenting cells processed the virus and presented most of the viral epitopes to T cells. Activated HIV-specific CD8 T cells were quantified by flow cytometry analysis as CD3CD8 IFNgamma producing T cells.


RESULTS
The CD8VIR assay reproducibly detected a large proportion of functional HIV-specific CD8 T cells responding to viral load rebound. The whole HIV particle stimulation used in the CD8VIR assay was comparable to the sum of Gag, Pol, Env and Nef stimulations. The percentage of HIV-specific CD8 T cells also significantly correlated with the percentage of Gag-specific cytotoxicity measured by the traditional Cr release assay. HIV-specific CD8 T cells correlated with immune control of HIV in chronically infected patients.


CONCLUSIONS
The CD8VIR assay quantifies the majority of HIV-specific CD8 T cells capable of killing HIV-infected cells during viral load rebound. This simple, versatile and reproducible assay can be performed from the specimen submitted for CD4 analysis. Upon clinical validation, the CD8VIR assay can be a new diagnostic tool to predict the control of viral load rebound after treatment interruption.
D001681:Biological Assay; D016827:CD8 Antigens / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000382:microbiology; D005434:Flow Cytometry; D015683:Gene Products, gag / Q000276:immunology; D015693:Gene Products, nef; D015684:Gene Products, pol / Q000276:immunology; D006678:HIV / Q000276:immunology*; D015658:HIV Infections / Q000175:diagnosis* / Q000276:immunology* / Q000821:virology; D006801:Humans; D066298:In Vitro Techniques; D019562:Viral Load; D038301:Virus Inactivation; D054311:nef Gene Products, Human Immunodeficiency Virus
D016827:CD8 Antigens; D015683:Gene Products, gag; D015693:Gene Products, nef; D015684:Gene Products, pol; D054311:nef Gene Products, Human Immunodeficiency Virus