EBV-transformed lymphoblastoid cell lines down-regulate EBNA in parallel with secretory differentiation.

Four monoclonal and one polyclonal lymphoblastoid cell line (LCL) were studied with regard to cytoplasmic immunoglobulin (cIg) expression, presence of the Epstein-Barr virus (EBV)-determined nuclear antigen (EBNA) and DNA synthesis. Each line was found to consist of two subpopulations, with only minimal overlap. Proliferating, EBNA-positive, cIg-negative cells formed the majority. The minority were EBNA-negative, contained abundant cIg and were largely non-proliferating. This suggests the continuous occurrence of a maturation process within each LCL. The concomitant down-regulation of EBNA raises the interesting question whether continued synthesis of the nuclear antigen is incompatible with differentiation for epigenetic reasons, or, alternatively, whether differentiation takes place when the viral genomes are suppressed or lost.