[In vitro enhancement of cytotoxicity of human peripheral blood lymphocytes with recombinant interleukin 2 and an interferon mixture (alpha + beta + gamma) against human colon carcinoma cell line SW1116].

The cytocidal effect of human peripheral blood lymphocytes (PBL's) enhanced by human recombinant interleukin 2 (IL-2) on human colon carcinoma cell line SW1116 was examined in vitro in the presence of plasma from patients with recurrence of colorectal carcinoma. In addition, human recombinant interferons alpha, beta, and gamma were combined to enhance this cytotoxicity of PBL's. Cytotoxicity of PBL's was enhanced by IL-2. Patients' plasma blocked the cytotoxicity of PBL's. Serially added IL-2 was able to maintain the enhanced cytotoxicity of PBL's in the presence of patients' plasma. The mixture of interferons (alpha + beta + gamma, or beta + gamma) directly killed target cells more efficiently than with single use of each interferon or other combinations of interferons. These mixtures of interferons (alpha + beta + gamma, or beta + gamma) also activated cytotoxicity of PBL's. The cytotoxicity of IL-2-activated PBL's was further enhanced by intermittent addition of the interferon mixture.