AUTOTUMOR REACTIVE CYTOTOXIC T-CELL RESPONSES IN B-CELL NON-HODGKINS-LYMPHOMA

We have generated cytotoxic T-lymphocytes (CTLs) from the peripheral b lood (PB) of eight B-cell non-Hodgkin's lymphoma (NHL) patients by in vitro coculture with autologous fresh tumor cells. Their functional ac tivity was assessed in Cr-51 release assay and was found to be MHC cla ss I restricted. Our results indicate the presence of T-cells cytotoxi c for autologous tumor cells in the PB of these patients but these wer e relatively small numbers in small lymphocytic lymphomas (SLLs). Trea tment of fresh tumor cells with rIFN-gamma and rTNF-alpha alone, or in combination significantly increased their susceptibility in 4/5 cases of SLLs, and a case of diffuse large cell lymphoma and Burkitt lympho ma (BL), while, B-cell lymphoma, rich in T-cells, did not show any app reciable increase. Fresh tumor cells were also analysed for MHC class I and ICAM-1 antigens by flow cytometry, in 5/8 cases before and after cytokine treatment. Significant upregulation of MHC class I antigens but with no detectable change in ICAM-1 observed in a case of SLL and BL, correlated with enhanced susceptibility. These findings suggest th e possible role of MHC class I antigens in the cytotoxic susceptibilit y of autologous tumor cells in B-cell NHL.