IMMUNE REGULATION WITHIN HUMAN TUMORS - CONTRIBUTION OF DIFFERENT COMPONENTS OF THE TUMOR MICROENVIRONMENT

We have examined the ability of various components of breast, colorect al and ovarian tumours to regulate the activation and function of LAK cells and TILs, immune effectors which have been used as anti-tumour t herapies. Tumour cell or supernatants derived from their short-term in vitro culture, inhibited the activation of PBMC by IL-2 but supported the continued proliferation of LAK or TIL cells which had already bee n activated. Despite being able to enhance or suppress growth of a ran ge of cell lines, a cell-free, soluble preparation (TDS) from primary tumours was uniformly inhibitory to IL-2 activated cells, suggesting t hat it reflected the immunoregulatory nature of human tumours more acc urately than cell-cultures or their supernatants.