Characterization of crossreactive T cell receptors that recognize both Epstein Barr virus and influenza A virus during acute influenza A virus infection (VIR5P.1135)

Abstract

Abstract Crossreactive CD8+T cells that recognize both influenza A (IAV) epitope M158, and Epstein Barr virus (EBV) epitope BRLF1109, are frequently found in HLA-A*02 populations particularly during acute infection. However, whether this crossreactivity is mediated by a single crossreactive T cell receptor (TCR) is unclear. To address this, M1- and BRLF1-MHCI oligomer positive CD8+T cells from peripheral blood of an acute IAV-infected patient who was EBV seropositive were single cell sorted and the TCR genes were sequenced and cloned. Thirty-three of 96 single cells yielded one TCRα and one TCRβ gene with 13 unique reproducible TCRα/β pairs. These 13 pairs of TCR genes were characterized in TCR deficient Jurkat cells expressing CD8α (J76) for antigen recognition and TCR signaling. In each case the transfected J76 cells bound strongly to M1-MHCI tetramer and weakly to BRLF1-MHCI tetramer consistent with the original staining in the peripheral blood. These crossreactive TCR-transfected J76 cells responded functionally to both peptides as they upregulated CD69 in response to BRLF1 as well as M1 peptide stimulation with four orders of magnitude difference. Interestingly, one TCR similar to JM22 which is a public TCR recognizing M1 epitope, was also crossreactive to BRLF1, which implies that many HLA-A*02 populations may be crossreactive to EBV. Our data clearly shows that crossreactivity between M1 and BRLF1 epitopes can be mediated by a single TCR and may be ubiquitous.