Proteome-wide analysis of CD8+ T cell responses to EBV lytic infection

Epstein-Barr virus (EBV) is one of 9 Human herpesviruses that can develop lifelong persistence. These viruses provide an antigenically complex challenge that induce strong CD8+T cell immunity during primary infection and continue to shape this immunity through recurrent lytic reactivation. Here is described the first lytic proteome-wide analysis of CD8+T cell responses to EBV and the first to compare primary vs memory CD8+T cell responses to any human herpesvirus. Primary CD8+T cells were mitogenically expanded directly from the blood of infectious mononucleosis (IM) patients. Comparatively, memory CD8+T cells required pre-enrichment using autologous dendritic cells loaded with a lytically-infected EBV cell lysate and FACS selection based upon the activation marker 4-1BB. Enriched cells were then expanded in vitro as for IM cells. Preparations from 7 IM patients and 7 healthy carriers were screened against each of the 70 EBV lytic cycle proteins in combination with the donors’ HLA-I alleles. Multiple reactivities were identified across the full lytic cycle with 146 responses identified amongst the 7 IM patients and 96 amongst the 7 healthy carriers. However the distribution of responses varied between the 2 cohorts with primary responses targeting IE and a small group of E proteins whereas memory responses targeted all phases but with some prominent responses against L proteins. This infers that responses in primary infection therefore appear to be shaped by presentation on the infected cell surface prior to the activity of viral evasins. However long-term carriage appears to re-shape the virus-specific response.