Evidence for nuclear antigens in cytomegalovirus-transformed human cells

Abstract

THE anti-complement immunofluorescence (ACIF) method has revealed an antigen localised in the nucleus of both producer and nonproducer cultures of lymphoblastoid cells carrying the Epstein–Barr virus (EBV) genome¹. Early nuclear antigens resembling the Epstein–Barr nuclear antigen (EBNA) have been detected in human embryo lung (HEL) cells as early as 3 h after infection with human cytomegalovirus (CMV)². These early antigens could be detected only by ACIF staining. We have reported³ that hamster embryo fibroblasts (HEF) transformed with ultraviolet-inactivated CMV exhibit cytoplasmic and perinuclear CMV-specific antigens when tested with CMV-immune sera in the indirect immunofluorescence (IF) test. We later noted that a human CMV of genital origin established a long-term persistent infection in HEL cells in vitro, which resulted in the development of two transformed cell lines after several cell culture passages⁴. CMV-specific antigens were demonstrated on the surface of the cells by the indirect IF technique. We have now investigated whether EBNA-like nuclear antigens can be detected in the CMV-transformed human cells with the ACIF technique, and whether there is a correlation of reactivity with early antigens of CMV-infected cells.