Factors influencing the establishment of tumour-infiltrating lymphocyte cultures from human breast carcinoma and colon carcinoma tissue

Tumour-infiltrating lymphocytes (TIL) were obtained from breast and colon tumour tissue and cultured in vitro in the presence of recombinant human interleukin-2. Seven of 35 breast tumours and five of 41 colon TIL cultures were established in vitro: proliferation rates of greater than 103 were achieved. The cytotoxic capacity of these cells was determined against the cell lines K562 and SW742, and percentage cytotoxicity levels of greater than 97% and 79%, respectively, were seen. An inverse relationship between the ability of TIL to kill and their proliferative capacity was observed in all cultures. The prominant phenotype was CD3 positive, with greater than 55% of TIL expressing this antigen; there was no expression of CD16. The expression of CD56 and CD25 varied, being maximumly expressed on 64% and 38% of TIL, respectively. When greater than 90% of TIL expressed CD3, the ability of the culture to kill the target cell lines was low; only when there was an increase in the proportion of cells expressing CD56 and a decrease in the expression of CD3 was there high cytotoxicity. This study indicates that the TIL which proliferate in vitro in the presence of interleukin-2 are not necessarily the mediators of cytotoxicity.