Integrated single-cell analysis of multicellular immune dynamics during hyper-acute HIV infection

Abstract

Abstract Development of effective vaccines and therapeutics is facilitated by understanding the earliest immune responses to infection. Here, we apply single-cell RNA-sequencing (scRNA-seq) and a novel gene module discovery-based framework to longitudinally profile peripheral multicellular immune responses in untreated hyper-acute HIV infection. We profiled >59,000 single cells from four individuals across multiple acute infection timepoints (including pre-infection), utilizing scRNA-seq data to identify transient immune responses with cell subset resolution. Onset of viremia induced interferon stimulated gene (ISG) responses integrated across multiple cell types, wherein monocytes notably contributed to the cytokine milieu. Otherwise obscured in bulk analyses, we describe a second set of responses following ISG upregulation that align in time: pro-inflammatory T cell differentiation, prolonged monocyte MHC-II upregulation, and persistent NK cytolytic killing. Leveraging our temporal, cell-type resolved data, we nominate putative cell-cell signaling networks and their key cytokines during infection. Two participants who later develop viremic control associated with elevated frequencies of proliferating cytotoxic cells, inclusive of a previously unappreciated NK cell subset, immediately following HIV detection. Our study reveals both cooperative and cell subset specific immune responses during untreated hyper-acute HIV infection with temporal resolution, nominating monocytes, NK cells, and pro-inflammatory signaling as perturbation targets for future vaccine studies. Moreover, our gene module discovery framework can be readily applied to other longitudinal studies in humans and other model organisms.