Surface IgM-kappa Specificity on a Burkitt Lymphoma Cell In Vivo and in Derived Culture Lines1

An exceptional Burkitt lymphoma patient, a 16-year-old boy, yielded tumor biopsy cells and derived tissue culture lines that displayed a strong surface accumulation of IgM heavy and kappa light chain specificities judged by direct membrane fluorescence and cytotoxicity tests. This property was main tained unchanged in the course of more than 5 months of serial passage in vitro. A fourth biopsy, obtained from the patient after massive necrosis had been induced in the tumor by cytosine arabinoside chemotherapy, did not show this property at either the biopsy stage or in the derived cell line. The pos sibility that the neoplastic transformation of lymphoid cells may have afflicted a cell specialized to carry immunoglobulin on its surface may be considered. The phenomenon has to be distin guished from immunoglobulin coating in vivo seen with certain biopsy samples from this and other patients. The latter type of coating can be of IgM, IgG, or IgA nature and disappears rapidly on cultivation in vitro.