Classification of cell lines derived from undifferentiated lymphomas according to their expression of complement and Epstein-Barr virus receptors: Implications for the relationship between African and American Burkitt's lymphoma

Abstract

Twenty-seven cell lines derived from undifferentiated lymphomas of Burkitt's and non-Burkitt's type, 26 of which possess the 8:14 chromosome translocation, have been characterized with regard to their expression of complement and Epstein-Barr virus (EBV) receptors and their susceptibility to theophylline-induced modification of receptor expression. The cell lines fall into six groups, three EBV nuclear antigen (EBNA) negative and three EBNA positive. The three EBNA-negative groups appear to represent different stages of differentiation—the first in which EBV to complement receptors are not expressed and cannot be induced, a second in which low levels of both receptors are expressed and induction of higher levels can be achieved with theophylline, and a third in which high levels of complement and EBV receptors are already present. EBNA-positive cell lines are either virus producers or virus nonproducers. Nonproducer lines fall into two groups which are distinguished by their degree of expression of complement receptor. The difference between the groups is particularly well shown by their ability of bind FBC at different temperatures (37 and 0.5°C). EBV producer lines express low levels of both EBV and complement receptors. These data suggest that tumors diagnosed histologically as undifferentiated lymphoma are neoplastic counterparts not of a single cell type, but of a spectrum of cell types, although together these cell types represent only a small part of the B-lymphocyte differentiation sequence. Whether individual tumors contain uniform cell population or cells at different stages of differentiation remains to be determined, but African and American tumors are primarily distinguished by their respectively low and high levels of expression of EBV and complement receptors.