Effect of bacillus Calmette-Guerin immunotherapy on tumor antigen-induced lymphocyte-stimulated protein synthesis in melanoma patients

Changes in in vitro lymphocyte-stimulation protein synthesis (SPS) of 40 melanoma patients following incubation with 3M KCl extracts of allogenic melanoma, lung carcinoma, and sarcoma antigens and phytohemagglutinin (PHA) were quantitated by measuring H³-leucine uptake. One of eleven "untreated"^* * "Untreated" refers to patients who had conventional surgical treatment for melanoma, but who did not receive BCG adjuvant therapy. melanoma patients stimulated significantly to the melanoma antigen. However, this lymphocyte response was not significantly different from that of the normal subjects. Patients who received systemic bacillus Calmette-Guerin (BCG) by the tine technique for 3 months and for 6 months had significant increase in lymphocyte protein synthesis following incubation with melanoma antigen. There were no significant differences in PHA responses between the "untreated" melanoma patients and the BCG-treated group. Testing of serial lymphocyte samples from nine melanoma patients before treatment and at monthly intervals thereafter confirmed these observations. Furthermore, no change in serial complement-fixing antibody titers to melanoma antigen was noted in the BCG-treated patients. These results demonstrated that in vitro lymphocyte responses to melanoma antigen may be augmented by BCG therapy.