A novel monoclonal antibody (BAT) to the B-lymphoblastoid cell line activates murine lymphocytes and exhibits a striking antitumor activity in mice. In order to evaluate the potential use of this antibody against human cancer, we have investigated its immuno-stimulatory properties on human peripheral blood lymphocytes (PBL). Our findings demonstrate that BAT mAb induces proliferation and cytotoxicity in human PBL against natural-killer-cell-sensitive and natural-killer-cell-resistant tumor cell lines. Interleukin-2 at a low concentration synergizes with BAT mAb in eliciting these effects. BAT mAb binds to human peripheral T cells as revealed by a double-labelling technique using anti-CD3 and BAT mAb. The molecular mass of the antigen recognized by BAT mAb was 48-50 kDa under reducing and non-reducing conditions. This study provides a basis for future experiments to evaluate the use of BAT mAb in the immunotherapy of cancer.

A novel monoclonal antibody (BAT) to the B-lymphoblastoid cell line activates murine lymphocytes and exhibits a striking antitumor activity in mice. In order to evaluate the potential use of this antibody against human cancer, we have investigated its immuno-stimulatory properties on human peripheral blood lymphocytes (PBL). Our findings demonstrate that BAT mAb induces proliferation and cytotoxicity in human PBL against natural-killer-cell-sensitive and natural-killer-cell-resistant tumor cell lines. Interleukin-2 at a low concentration synergizes with BAT mAb in eliciting these effects. BAT mAb binds to human peripheral T cells as revealed by a double-labelling technique using anti-CD3 and BAT mAb. The molecular mass of the antigen recognized by BAT mAb was 48-50 kDa under reducing and non-reducing conditions. This study provides a basis for future experiments to evaluate the use of BAT mAb in the immunotherapy of cancer.

Monoclonal antibodies were prepared against native human ovarian carcinoma cells derived from the ascitic fluid of a patient (BH). One antibody, HC7R7, was selected on the basis of its binding to tumor BH cells, to other ovarian tumor cell lines (CAOV-3 and GZL-8), but not to the patient's fibroblasts. One hundred cell smears from ascitic and pleural effusions of tumor-suspected patients were immunostained with HC7R7. All serous ovarian carcinomas and half of the breast carcinomas stained positive with HC7R7; cells from noncancer ovarian aspirates were negative. Mesothelial cells were also stained with HC7R7. A correlation was noted between HC7R7 and OC-125 staining of ovarian tumor cells but not between HC7R7 and c-neu staining of breast tumor paraffin sections. The location of HC7R7-positive material in ovarian tumor cell lines (CAOV-3 and GZL-8) differed from that in the breast tumor cell line (MCF-7). CAOV-3 and GZL-8 showed membrane binding while, in MCF-7, not fully identified intracellular organelles were stained. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis and immunoblots from membrane and cytosol fractions of GZL-8 and MCF-7 showed HC7R7 binding to three protein bands in the membrane fraction and to three other bands in the cytosol, all in the 29- to 68-kDa range. Two of the bands were glycoproteins. The only band that was different in the GZL-8 and MCF-7 cells was a 43-kDa glycoprotein, which was more pronounced in the MCF-7 cells. The possible significance of the new HC7R7 antibodies for detection and survey of ovarian malignancies is discussed.