Comprehensive evaluation of the CD8 responses to HSV-1 in humans (105.41)

Abstract

CD8-only vaccines can be protective on some mouse models. HSV-1-specific CD8s localize to sites of lesion and healed skin, and to chronically infected ganglion. We enriched polyclonal HSV-1-specific CD8s from human blood using a novel cross-presentation/activation marker-based protocol. After expansion, these cell populations were quite oligoclonal as assessed by TCR beta chain CDR3 deep sequencing. To query fine specificity, artificial APC were created by transfecting Cos-7 cells with each HLA A or B heavy chain from the subject. Each HSV-1 ORF was cloned into an expression vector and separately co-transfected with each HLA allele. Activation of CD8+ cells in the polyclonal T-cell population to specific ORFs was detected by interferon-gamma ELISA. The complexity of the response ranged from 7 to 23 reactive ORF/HLA combinations per subject. Most such epitopes are HSV-1 type-specific, but some are identical within the related pathogen HSV-2. One type-common epitope was studied in HLA A*0201-transgenic mice, in which DNA vaccination with the HSV-1 full-length ORF lead to very strong epitope-specific responses. Overall, we observed a remarkably similar complexity for the CD8 response to HSV-1 by using either the deep TCR sequencing or antigenic specificity method. Novel candidate immunodominant HSV-1 CD8 antigens were identified, and no apparent skewing to virion input or immediate early proteins due to TAP inhibition was detected.