Susceptibility of B-cell lymphoma to human antibodies encoded by the V4-34 gene.

Our previous studies have shown that mAbs derived from the human V4-34 gene bind and kill human B-lymphocytes via membrane disruption. This study demonstrates the cytotoxicity of two V4-34 encoded mAbs, 216 and Z2D2, towards human B-cell lymphoma. In vitro, 216 and Z2D2 are cytotoxic to a variety of B-cell lymphomas obtained from patient biopsies. In vivo, increased survival was observed with both mAbs in a lymphoma model developed in scid mice with human B-cell line Nalm-6. Studies in mice show that these mAbs are well tolerated with minimum side effects. Since 216 and Z2D2 show increased toxicity towards cycling cells, V4-34 mAb-based therapy can be additive with drugs that block cell-cycle progression. Stem cells that are V4-34 mAb ligand negative would not be depleted. Together, these studies recommend an evaluation of the two completely human mAbs in a phase I trial for B-cell lymphoma.