A novel monoclonal antibody with immunestimulatory and anti-tumor properties

We have raised a novel monoclonal antibody (BAT MAb) to Daudi B lymphoblastoid cell line. This antibody stimulates both human and mouse lymphocytes. BAT MAb has a striking antitumor effect on different mouse tumor models. This is manifested by tumor regression and by prolonged survival. Adoptive transfer of splenocytes from mice which had been inoculated with B-16 melanoma and treated with BAT MAb into recipients bearing either melanoma or 3LL carcinoma tumors also resulted in tumor regression. BAT MAb is also effective in the regression of human tumors. BAT failed to induce regression of SK-28 human melanoma inoculated (i.v.) into SCID mice. Engraftment of human PBL into SCID mice rendered the tumor bearing mice (pulmonary lesions) responsive to BAT. Experimental in vivo data support the notion that the tumor and BAT synergizes in the activation of the host immune system. In vitro studies in which mouse or human lymphocytes were co-cultured with tumor cells and BAT MAb, showed a synergistic effect in the induction of lymphocyte proliferation. FACS analysis revealed that BAT induced the generation of CD3/CD56 positive lymphocytes. These cells may also be involved in the anti-tumor effect. These findings form a base for the potential clinical use of this antibody.