CELLULAR IMMUNOLOGY 123,325-333 (1989) Human T Cell Responses to the Epstein-Barr Nuclear Antigen-l (EBNA-1) as Evaluated by Synthetic Peptides’ J~RGEN PETERSEN, GARY RHODES, KEVIN PATRICK,* JEAN ROUDIER, AND JOHN H. VAUGHAN Research Institute ofScripps Clinic, Department ofBasic and Clinical Research, 10666 North Torrey Pines Road, La Jolla, California 92037, and *San Diego State University, Student Health Services, 5300 Campanile Street, San Diego, California 92182 Received April 24, 1989; accepted July 6, 1989 A panel of synthetic peptides derived from Epstein-Barr virus (EBV) nuclear antigen 1 (EB- NA-1) was used to examine human T cell responses to this antigen. In six of seven normal persons with past EBV infection, T cell precursors specific for five peptides (P27, amino acid residues 83-101; P62, 148-166; E31, 353-367; E41, 368-381; and El 1,461-474) were detect- able. The precursor frequencies were in the range of 1:20,000 to < 1:100,000 peripheral blood mononuclear cells as determined by limiting dilution analyses. Only two of these peptides were predicted as a-helices; all peptides were glycine-rich. Four other peptides were not reactive in the seven individuals tested. T cell responseswere not detectable in donors without prior EBV infection. Infectious mononucleosis patients investigated 4-6 weeks after diagnosis had likewise no detectable peptide-specific T cell precursors. Thus, it appears that T cells recognizing peptides from EBNA-I arise and persist in people with past EBV infection. o 1989 Academic press, IX. INTRODUCTION Epstein-Barr virus (EBV)2 is a ubiquitous human herpes virus that infects the ma- jority of the population. The infection persists for life, B cells serving as a reservoir. EBV infection is the cause of infectious mononucleosis (IM) and has been associated with other clinical disorders, such as Burkitt lymphoma, nasopharyngeal carcinoma, and immunodeficiency syndromes. Human B lymphocytes latently infected with EBV express at least five nuclear antigens (EBNAs) (l-3) and a membrane antigen (LMP) (4). B lymphocytes produc- tively infected with EBV express additional viral antigens, such as viral capsid anti- gens (VCA) and viral membrane antigens (5). EBNA- 1 is the nuclear antigen in la- tently infected cells that is recognized most frequently by IgM and IgG antibodies ’ This work was supported in part by the Danish Rheumatism Association, Wedell-Wedellborgs Founda- tion, Association pour la Recherche contre le Cancer, Philippe Foundation, and Grants AR21 175, AR33489, AR25443, and RR00833 from the National Institutes of Health. This is Publication 5476BCR from the Research Institute of Scripps Clinic. * Abbreviations used: EBNA, Epstein-Barr nuclear antigen; EBV, Epstein-Barr virus; IM, infectious mononucleosis; VCA; viral capsid antigen. 325 0008-8749/89 $3.00 Copyright 0 1989 by Academic Press, Inc. All rights of reproduction in any form reserved.