Proteome-wide analysis of CD8+ T cell responses to EBV reveals differences between primary and persistent infection

Abstract

Human herpesviruses are antigenically rich agents that induce strong CD8+T cell responses in primary infection yet persist for life, continually challenging T cell memory through recurrent lytic replication and potentially influencing the spectrum of antigen-specific responses. Here we describe the first lytic proteome-wide analysis of CD8+ T cell responses to a gamma1-herpesvirus, Epstein-Barr virus (EBV), and the first such proteome-wide analysis of primary versus memory CD8+ T cell responses to any human herpesvirus. Primary effector preparations were generated directly from activated CD8+ T cells in the blood of infectious mononucleosis (IM) patients by in vitro mitogenic expansion. For memory preparations, EBV-specific cells in the blood of long-term virus carriers were first re-stimulated in vitro by autologous dendritic cells loaded with a lysate of lytically-infected cells, then expanded as for IM cells. Preparations from 7 donors of each type were screened against each of 70 EBV lytic cycle proteins in combination with the donor’s individual HLA class I alleles. Multiple reactivities against immediate early (IE), early (E) and late (L) lytic cycle proteins, including many hitherto unrecognised targets, were detected in both contexts. Interestingly however, the two donor cohorts showed a different balance between IE, E and L reactivities. Primary responses targeted IE and a small group of E proteins preferentially, seemingly in line with their better presentation on the infected cell surface before later-expressed viral evasins take full hold. By contrast, target choice equilibrates in virus carriage with responses to key IE and E antigens still present but with responses to a select subset of L proteins now often prominent. We infer that, for EBV at least, long-term virus carriage with its low level virus replication and lytic antigen release is associated with a re-shaping of the virus-specific response.

Immunology of EBV-Related Lymphoproliferative Disease in HIV-Positive Individuals

“…However, CD8+ T cells with responces to both lytic and latent epitopes derived from BMLF-1, EBNA-3A, LMP-1, LMP-2, and pp65 have been reported in convalescent subjects, indicating the long term prevalence of EBV-specific T cells in latently infected individuals (78,79,82,83). A comparison between responses to immediate early, early and late lytic EBV protein epitopes in activated CD8+ T cells derived from patients with IM and memory CD8+ T cells from patients with chronic EBV showed that patients with IM had most prominent responses to immediate early and early lytic epitopes, while long term EBV carriers have demonstrated highest cytotoxic T cell responces to late lytic viral proteins, suggesting that anti-viral immune responses are modulated in different EBV infection stages (84).…”

Assessing Anti-HCMV Cell Mediated Immune Responses in Transplant Recipients and Healthy Controls Using a Novel Functional Assay

“…Indeed, this is consistent with HCMV being asymptomatic in healthy individuals due to effective immune control. What this may reflect is that incoming HCMV proteins are processed and presented for T cell recognition prior to the virus interfering with this process, as has been suggested for Epstein-Barr virus (Forrest et al, 2018). It should also be noted that the ability of some HCMV immunoevasins to prevent MHC class I processing and presentation is dependent on the genotype of the host [e.g., US2 cannot bind HLA-B * 07 and * 27 as efficiently as HLA-A genotypes (Gewurz et al, 2001;Reddehase, 2002); US11 degrades HLA-A but is less effective against HLA-B, with HLA-B * 44:02 particularly resistant (Zimmermann et al, 2019)].…”

Immunogenic particles with a broad antigenic spectrum stimulate cytolytic T cells and offer increased protection against EBV infection ex vivo and in mice

“…The ability of B cells to efficiently present several structural proteins from incoming virions to CD4 + T cells [35,40] suggests that structural protein-specific CD4 + T cells are likely to play a more dominant role than CD8 + T cells during the very early stages of infection. However, the recent identification of BcLF1-specific T-cell clones that can recognize LCLs pulsed with UV-inactivated EBV [41] suggests that structural protein-specific CD8 + T cells may also play an important role during the early stage of infection. In contrast, we found that LCLs pulsed with modified EBV VLPs were unable to stimulate an EBNA1-specific CD8 + T-cell clone, implying that cross-presentation might be limited to particular structural antigens.…”