Enhancement of the lytic activity of cloned human CD8 tumour-infiltrating lymphocytes by bispecific monoclonal antibodies

Abstract

We have isolated tumour-infiltrating lymphocytes (TIL) clones from a patient with renal cell cancer. The cloning frequency and the effector function were measured. No difference in cloning frequency (r2 = 0.97, frequency = 1:13) was observed between TIL expanded with allogeneic versus autologous feeder cells. Sixty-four clones expanded with autologous feeder cells and 37 clones expanded with allogeneic feeder cells were assayed for cytolytic activity on an autologous primary renal cell carcinoma (RCC) culture, an allogeneic RCC line, and on the K562 and Daudi cell lines. Most of these clones were also phenotyped. Although TIL clones expressing cytotoxic activity for RCC lines could be generated with both feeder cell preparations, none of the clones tested showed specificity for cells from autologous primary RCC cultures. However, in the presence of relevant bispecific MoAbs (alpha OC/TR) all CD8+ TIL clones tested could be induced to lyse autologous RCC cultures. Furthermore, the cytolytic activity of all CD8+ clones tested against allogeneic RCC lines could be induced or further enhanced by alpha OC/TR or CD3/G250 bispecific MoAbs. In contrast, none of the CD4+ clones tested showed lytic activity. Quantitatively the cytotoxic response in the presence of alpha OC/TR or CD3/G250 of CD8+ TIL clones against G250+ and MOv18+ cell lines appears to be associated with the level of antigen expression on the target cells. Our results suggest that: (i) expansion of TIL with allogeneic or autologous feeder cells does not effect the lytic profile of the clones; (ii) the use of bispecific MoAbs may overcome a lack of specificity of cytotoxic T lymphocytes.