Two Epstein-Barr viral nuclear neoantigens distinguished by gene transfer, serology, and chromosome binding

We recently identified, by means of cotransformation of LTK- cells, a region of the Epstein-Barr virus (EBV) genome (the BamHI K fragment) that encodes or induces an EBV nuclear neoantigen (EBNA) serologically related to the EBNA found in lymphoid cells carrying the entire EBV genome. We now find that a second EBV DNA fragment, BamHI M, is also able to give rise to cotransformed LTK- cells with stable expression of a nuclear antigen. The BamHI K and M fragments have no apparent DNA homology. Many human sera that are reactive to EBNA in Raji cells detect both antigens; however, certain anti-EBNA-positive human sera are discordant and react only with the BamHI M or only with the BamHI K nuclear antigen. Every Raji cell appears to express both "M" and "K" antigens; D98 Raji cells, a somatic cell hybrid, express only "K" antigen. The K antigen is found on metaphase chromosomes of LTK cells and Raji cells. The M-induced antigen is not located on chromosomes when the cells are in metaphase but is present as granules within the nucleus.