Abortive expression of the Epstein-Barr virus (EBV) cycle in a variety of EBV DNA-containing cell lines, as reflected by nucleic acid hybridization in situ

Abstract

A variety of Epstein-Barr virus (EBV) DNA-containing cell lines have been tested for the expression of the EBV-associated antigens EBNA (nuclear antigen), EA (early antigen), and VCA (viral capsid antigen), and for the presence of cells containing disproportionate amounts of EBV DNA. The antigen tests utilized immunofluorescence and 125I-labelled antibodies combined with autoradiography. EBV-DNA was detected by in situ hybridization with 3H-labelled EBV RNA complementary to P3HR-1 EBV DNA (P-EBVcRNA). The P-EBVcRNA has been shown to represent the majority of the P3HR-1 EBV DNA sequences. It was concluded that EBV DNA-containing cell lines can be divided into those that express only EBNA, those that express EBNA and EA and those that express EBNA, EA and VCA and also contain cells that undergo disproportionate EBV DNA synthesis. Consequently, in some cell lines there is an abortive expression of the EBV cycle in that some cells spontaneously express EA but fail to continue further to viral DNA synthesis. A similar pattern can be found after experimental induction of the EBV cycle, suggesting that related mechanisms govern the spontaneous expression of the EBV cycle and the extent of its inducibility.