Role of killer cell immunoglobulin-like receptors in the functional modulation of NK cell response to HIV-1 viral reservoirs in individuals on antiretroviral therapy

Abstract

Sub-Saharan Africa has two thirds of the global population living with HIV. Uganda has one of the highest burdens of HIV/AIDS globally, with a significant proportion of individuals on antiretroviral therapy. Complete remission to HIV is still not achieved by individuals on suppressive ART therapy. Studies have been conducted in Italy and in USA looking at how NKp44/Nkp30, NKG2D and blockade of NKG2A receptors on NK cells which can aid in the elimination of viral reservoirs. However, few studies are available in Sub-Saharan Africa as well as in Uganda in the use of NK cells to eradicate HIV viral reservoirs as well as how the Killer cell immunoglobulin-like receptors modulate NK cell function in the elimination of viral reservoirs. To determine the size of HIV-1 viral reservoirs and its association with KIRs on NK cells in individuals who have been on ART for more than 4 years. This was a longitudinal retrospective study using archived samples from the Rakai Community Cohort Study. To determine the frequency of NK cells expressing activating killer cell immunoglobulin-like receptors, NK cells were negatively isolated using an NK cell isolation. DNA was extracted using QIAamp DNA Mini Kit, ensuring high quality genomic material. Specific loci for KIR and HLA genes were amplified by PCR, using primers designed for each gene’s unique sequence regions. KIR genes were genotyped through Sanger sequencing, while HLA class I genes underwent high resolution genotyping using Next generation Sequencing. Sequence data were processed using alignment and variant calling software. To determine the frequency of latent HIV infection, resting CD4+ T cells were negatively isolated. The resting CD4+ T cells were then stimulated in limiting dilutions with PHA and γ- irradiated PBMC and co-cultured with MOLT-4 cells. The co-culture supernatant was then tested by ELISA for p24 on days 14 and 21. This study focused on the capability of NK cells expressing activating killer cell immunoglobulin-like receptors to eliminate HIV-1 viral reservoirs.