ISOLATION OF TUMOR-DERIVED IMMUNOGLOBULIN-IDIOTYPE FROM PERIPHERAL-BLOOD MONONUCLEAR-CELLS IN A B-CELL LYMPHOMA PATIENT WITH MINIMAL DISEASE

Active immunization with autologous idiotypic immunoglobulin, obtained by somatic fusion techniques, has been shown to be a useful alternati ve treatment in patients with B-cell lymphoma. Nevertheless, the requi rement for biopsy specimens to obtain lymphoma cells could be a limita tion to this therapeutic strategy. We address the question of whether peripheral blood samples containing small amounts of tumor cells can b e used as appropriate fusion partners to rescue tumor-derived idiotypi c proteins. In this report, we show that hybrid cells can be obtained from somatic fusions of K6H6/B5 heterohybridoma with lymphoma cells ob tained from both lymph node (LN) and peripheral blood mononuclear cell s (PBMC) containing only minor amounts of tumor cells. Some hybrid cel ls obtained from LN or PBMC fusions present an immunoglobulin (Ig) hea vy-chain gene rearrangement identical with that of the original tumor and secrete identical Ig protein containing the expected H and L chain s.