Protein Studies of the Epstein-Barr Virus in Ethnically Diverse Populations

Epstein Barr virus (EBV) can induce in immune compromised patients fatal lymphoproliferative lesions that regress upon reversion of immune suppression or adoptive transfer of EBV-specific CD8+ T cells. EBV can also induce neoplastic lesions in immune competent hosts including Burkitt's lymphoma, Hodgkin's disease and nasopharyngeal cancer (NPC). EBV-specific CD8+ T cell responses can occur in patients with these cancers that are qualitatively similar but quantitatively diminished compared to EBV-primed normal individuals. Although these cancers share several features, they are characterized by divergent patterns of expression of EBV proteins. In particular, NPC expresses preferentially the latent membrane protein (LMP) 2 with or without expression of LMP 1 and intermediate expression of the Epstein-Barr nuclear antigen. Thus, there is interest to develop LMP 2-directed immunizations for patients with NPC with the hope that enhancement of the insufficient natural immunity may lead to tumor regression. Since, the incidence of NPC is tightly associated with ethnic background (principally Southern Chinese) and Human Leukocyte Antigen (HLA) phenotype, diverse populations may display distinct reactivity patterns toward EBV epitopes that may in turn be responsible for their respective predisposition to acquire NPC. Although, several LMP 2 epitopes have been described, to our knowledge, no systematic mapping across diverse ethnicity complemented with high-resolution HLA typing has ever been done. We, therefore, propose to map immune dominant epitopes of LMP 2 in EBV primed normal individuals of Caucasian or Asian (Chinese) ethnicity by measuring interferon (IFN)-gamma transcript levels in circulating lymphocytes exposed to a library of overlapping nonamer peptides encompassing the full sequence of LMP 2. High resolution, sequence-based HLA typing will complement the study.