Human CD4(+) T lymphocytes consistently respond to the latent Epstein-Barr virus nuclear antigen EBNA1.
The Epstein-Barr virus (EBV)-encoded nuclear antigen EBNA1 is critical for the persistence of the viral episome in replicating EBV-transformed human B cells. Therefore, all EBV-induced tumors express this foreign antigen. However, EBNA1 is invisible to CD8(+) cytotoxic T lymphocytes because its Gly/Ala repeat domain prevents proteasome-dependent processing for presentation on major histocompatibility complex (MHC) class I. We now describe that CD4(+) T cells from healthy adults are primed to EBNA1. In fact, among latent EBV antigens that stimulate CD4(+) T cells, EBNA1 is preferentially recognized. We present evidence that the CD4(+) response may provide a protective role, including interferon gamma secretion and direct cytolysis after encounter of transformed B lymphocyte cell lines (B-LCLs). Dendritic cells (DCs) process EBNA1 from purified protein and from MHC class II-mismatched, EBNA1-expressing cells including B-LCLs. In contrast, B-LCLs and Burkitt's lymphoma lines likely present EBNA1 after endogenous processing, as their capacity to cross-present from exogenous sources is weak or undetectable. By limiting dilution, there is a tight correlation between the capacity of CD4(+) T cell lines to recognize autologous B-LCL-expressing EBNA1 and DCs that have captured EBNA1. Therefore, CD4(+) T cells can respond to the EBNA1 protein that is crucial for EBV persistence. We suggest that this immune response is initiated in vivo by DCs that present EBV-infected B cells, and that EBNA1-specific CD4(+) T cell immunity be enhanced to prevent and treat EBV-associated malignancies.
Münz
C
C
Laboratory of Cellular Physiology and Immunology, The Rockefeller University, New York, New York 10021-6399, USA.
Bickham
K L
KL
Subklewe
M
M
Tsang
M L
ML
Chahroudi
A
A
Kurilla
M G
MG
Zhang
D
D
O'Donnell
M
M
Steinman
R M
RM
D000328:Adult; D017951:Antigen Presentation; D001402:B-Lymphocytes / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D003713:Dendritic Cells / Q000276:immunology; D000939:Epitopes / Q000737:chemistry / Q000235:genetics; D019309:Epstein-Barr Virus Nuclear Antigens / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000276:immunology; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000096:biosynthesis; D008213:Lymphocyte Activation; D017434:Protein Structure, Tertiary; D020449:Repetitive Sequences, Amino Acid
D000939:Epitopes; D019309:Epstein-Barr Virus Nuclear Antigens; D007371:Interferon-gamma