A serologic study of cultured breast cancer cell lines: lack of antibody response to tumour specific membrane antigens in patients.

Humoral antibodies to tumour associated membrane antigens of cultured human breast cancer cell lines were studied using the immune adherence (IA) test. Sera from 353 post-operative breast cancer patients and from twenty-five patients immunized by allogeneic breast cancer cells were tested against the MDA-MB-436 cell line. Fifty-five (15.6%) sera samples from the non-vaccinated group and 131 (77.3%) of 168 sera samples from the immunotherapy group were IA-positive to this cell line after absorption with bovine erythrocytes to exclude antibody to heterologous membrane antigens (HM Ag). Forty-five of the 55 positive-sera from the non-immunized group and 113 of the 131 positive sera from the immunized group became IA-negative after further absorption with lymphoblastoid cells autologous to MDA-MB-436. Subsequently, the twenty-eight positive sera remaining sere tested for oncofetal antigens (OFA). After absorption with OFA rich tissues (fetal brain and M14 melanoma cells), no reactivity remained in the sera samples. In order to identify antibodies specific to breast cancer antigens, the 129 sera samples from non-immunized patients were tested against four other breast cancer cell lines; MDA-MB-157, MDA-MB-231, MCF-7 and UCLASO-B1. Four sera which reacted to more than three of the cell lines were identified. The reactivity of three of the four was due to anti-OFA antibody. The last serum sample was reactive to anti-HLA antibodies. These results indicate that sera of patients with breast cancer contain antibodies to OFA, but do not detect breast histologic type specific antigens as tested by IA using five breast cancer cultured cell lines.