Project description:We have employed a single-cell sequencing approach using 10X Genomics 5'scRNAseq to study expression of the Major Histocompatibility Complex (MHC) in peripheral blood mononuclear cells (PBMC) from Mauritian-origin cynomolgus and Indian-origin rhesus macaques. The MHC region has undergone a complex series of duplications in macaques relative to humans. Steady-state RNA levels of macaque MHC class I and class II transcripts vary over several orders of magnitude in whole blood and bulk PBMC. This study represents the first 5'scRNAseq analysis to quantify allele-specific levels of MHC transcripts in various PMBC subsets of macaques and provides insights into how they may shape immune responses.
Project description:Recent discoveries highlight the effectiveness of major histocompatibility complex (MHC)-E-restricted CD8+ T cell responses in controlling certain infections, particularly in a rhesus cytomegalovirus (RhCMV68-1)-vectored simian immunodeficiency virus (SIV) vaccine. In this context, these responses are preferentially elicited and are crucial for enabling vaccinated rhesus macaques to eradicate an SIV challenge. To harness human leukocyte antigen (HLA)-E-restricted CD8+ T cell responses for therapeutic purposes, it is essential to understand how these responses are primed, especially the mechanisms regulating MHC-E trafficking within endosomal pathways. Here, we identified a novel lysine/tryptophan-based motif in the HLA-E cytoplasmic tail that promotes rapid surface turnover via clathrin-mediated endocytosis. This motif, combined with strong binding peptides, also facilitates HLA-E recycling through a distinct valosin-containing protein-dependent pathway. Additionally, we show that this motif and its associated endosomal transport mechanisms are conserved in rhesus macaques and Mauritian-origin cynomolgus macaques. These findings advance our understanding of how MHC-E regulates immune functions through unconventional transport processes and offer insights for stimulating HLA-E-restricted CD8+ T cell responses in immunotherapy development.
Project description:The peptide-loading complex (PLC) is a transient, multisubunit membrane complex in the endoplasmic reticulum (ER), essential for establishing a hierarchical immune response. The PLC coordinates peptide translocation into the ER with loading and editing of major histocompatibility complex class I molecules (MHC-I). After final proofreading in the PLC, stable peptide/MHC-I complexes are released to the cell surface to evoke a T-cell response against infected or malignant cells. Sampling of different MHC-I allomorphs requires the precise coordination of seven different subunits into a single macromolecular assembly, including the transporter associated with antigen processing TAP1/2, the oxidoreductase ERp57, the MHC-I heterodimer, and the chaperones tapasin and calreticulin. The molecular organization and mechanistic events in the PLC are unknown due to the compositional heterogeneity and intrinsic dynamic nature of the complex. Here, PLC from Burkitt’s lymphoma cells was isolated using an engineered viral inhibitor as bait, followed by cross-linking mass spectrometry to aid EM structure elucidation.
Project description:Characterisation of peptide ligands of the Major histocompatibility class (MHC) I allele, HLA-B*57:01, expressed in the C1R (Class I reduced) B-lymphoblastoid cell line, after exposure to the anti-retroviral abacavir or abacavir analogues.
Project description:Characterisation of the kinetics of abacavir-induced perturbation of the immunopeptidome of the Major Histocompatibility Complex (MHC) class I molecule HLA-B*57:01.
Project description:Rhesus macaques vaccinated by rhesus cytomegalovirus vectors expressing simian immunodeficiency virus proteins (RhCMV/SIV) activate gene expression signature associated with IL15. To examine the gene expression signature activated by IL15, we performed longitudinal examinations of rhesus macaques during IL15 treament.
