Antibody-dependent cellular cytotoxicity to human colon-tumour cells. I. Lack of tumour specificity in a population study

Abstract

Summary.-The humoral and cellular components of the antibody-dependent cellular cytotoxicity (ADCC) against allogeneic human colonic tumour cell lines were evaluated. The 2 colon cell lines used in this study non-cancer patients were tested, using the reaction with heterologous anti-CEA as positive control and as a reference point. In 46 cases (21 %) the sera were reactive in this system, and 43 of them were of Blood Group 0. However, there was no difference between the cancer patients and the normal controls. The antigenic determinant involved in this reaction is not the Blood Group A specificity but, most probably, a polypeptide common to CEA and A (as shown in the following publication). In addition, trials for the elimination of the non-tumour-specific reaction, by absorption or inhibition, failed to disclose a tumour-specific one. The value of the ADCC assay in monitoring human tumour immunity, and possible ways of eliminating reactivity to normal antigens in this system, are discussed in the light of these findings.