ACTIVATION OF HUMAN-LYMPHOCYTES BY A MONOCLONAL-ANTIBODY TO B-LYMPHOBLASTOID-CELLS MOLECULAR-MASS AND DISTRIBUTION OF BINDING-PROTEIN

A novel monoclonal antibody (BAT) to the B-lymphoblastoid cell line ac tivates murine lymphocytes and exhibits a striking antitumor activity in mice. In order to evaluate the potential use of this antibody again st human cancer, we have investigated its immune-stimulatory propertie s on human peripheral blood lymphocytes (PBL). Our findings demonstrat e that BAT mAb induces proliferation and cytotoxicity in human PBL aga inst natural- killer-cell-sensitive and natural-killer-cell-resistant tumor eel 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 provi des a basis for future experiments to evaluate the use of BAT mAb in t he immunotherapy of cancer.