Comparison of a rabbit heteroantiserum and a murine monoclonal antibody raised against a human epithelial ovarian carcinoma cell line

An ovarian carcinoma cell line (OVCA 432) and a B-lymphocyte line (LAZ 446) were established from the same donor. A heteroantiserum (D-100) was prepared in rabbits against OVCA 432 and absorbed with LAZ 446, human AB erythrocytes, and the CX-1 colorectal cell line. After absorption, D-100 reacted by indirect immunofluorescence with six of six epithelial ovarian carcinoma cell lines and cryostat sections of 18 of 18 epithelial ovarian tumors but bound to zero of 12 nonovarian tumor cell lines. Despite a lack of reactivity with nonovarian tumor cell lines, D-100 reacted with epithelial components of normal ovary, fallopian tube, endometrium, endocervix, breast, colon, and epididymis. A murine monoclonal antibody (OC 133) was also raised against OVCA 432 and selected for lack of reactivity with the autologous B-lymphocyte line LAZ 446. OC 133 reacted with six ovarian carcinoma cell lines and cryostat sections of seven of 19 ovarian tumors, but it also reacted with five of five nonovarian tumor cell lines. Of 12 normal tissues examined, OC 133 reacted with endometrium and endocervix only. Whereas D-100 bound to serous, mucinous, endometrioid, and clear cell ovarian neoplasms, OC 133 bound only to serous tumors. In developing monoclonal reagents, cell lines may provide a useful source of antigen, but promising antibodies should be screened for reactivity with sections of normal and malignant human tissues.