Idiotypic immunoglobulin secretion by human B cell non-Hodgkin's lymphomas is related to the expression of the interleukin-2 receptor.
Tumor cells from 5 human B cell non-Hodgkin's lymphoma (B-NHL) patients were investigated for proliferative activity and idiotypic (Id+) immunoglobulin (Ig) secretion in serum-free medium without deliberate addition of B cell growth or differentiation factors (BCDF). These data were compared with cell surface marker expression, notably of activation antigens such as 4F2 and interleukin-2 (IL-2) receptor. Cells from all patients became 4F2 positive at the end of the 6-day culture period. Freshly drawn cells from 3 out of 5 patients expressed the IL-2 receptor (CD25; Tac antigen) or acquired this marker during culture in vitro and secreted relatively high levels of Id+ Ig in vitro. This correlated with elevated serum Id levels (greater than or equal to 0.5 micrograms/ml in vitro versus greater than or equal to 20 micrograms/ml in vivo). In the 2 CD25 (Tac)- B-NHL patients serum Id levels were below the detection limit and the amount of Id+ Ig secreted in vitro did not surpass 50 ng/ml. Only the B-NHL cells from a single patient were initially CD25 (Tac) positive and only these cells proliferated in serum-free culture. To test whether IL-2 receptor expression in the 3 CD25 (Tac)+ patients was functional, recombinant IL-2 (rIL-2) either alone or in conjunction with BCDF and recombinant IL-4 (rIL-4) was added to the cultures. In 2 out of 3 CD25 (Tac)+ patients rIL-2 was capable of enhancing proliferation or Ig secretion. In addition rIL-2 was found to enhance BCDF-mediated but not rIL-4 mediated responses. The third CD25 (Tac)+ B-NHL population was resistant to any of these lymphokines. Thus, this serum-free culture system may accurately reflect patient serum Id levels. IL-2 appears to regulate not only the in vitro but also the in vivo Ig secretion by neoplastic B cells.
D000954:Antigens, Surface / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology; D002455:Cell Division / Q000187:drug effects; D006801:Humans; D007130:Immunoglobulin Idiotypes / Q000378:metabolism*; D007075:Immunoglobulin M / Q000378:metabolism; D007376:Interleukin-2 / Q000494:pharmacology; D015847:Interleukin-4; D007378:Interleukins / Q000494:pharmacology; D008228:Lymphoma, Non-Hodgkin / Q000032:analysis / Q000276:immunology* / Q000473:pathology; D010641:Phenotype; D011971:Receptors, Immunologic / Q000032:analysis*; D015375:Receptors, Interleukin-2; D014407:Tumor Cells, Cultured
D000954:Antigens, Surface; D007130:Immunoglobulin Idiotypes; D007075:Immunoglobulin M; D007376:Interleukin-2; D007378:Interleukins; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D015847:Interleukin-4