In an attempt to construct biphasic monoclonal antibodies (bimAbs) able to target cytotoxic T lymphocytes against human hepatoma cells, an HGPRT-deficient mutant of the Hepama-6 hybridoma, which produces an antihuman-hepatoma mAb, was directly fused with splenocytes from Balb/C mice immunized by a polyclonal cytotoxic T-cell line. Hybrid hybridomas were selected in HAT medium, and their supernatants were directly screened for the ability to induce IL-2-cultured cytotoxic T lymphocytes to kill hepatoma cells in a 51Cr-release assay. The selected hybrid hybridoma, termed DQ-33, secretes a bimAb, which reacts with a CD3-associated determinant. When resting peripheral-blood lymphocytes were used as effector cells, virtually no cytolytic activity could be induced by DQ-33, whereas phytohemagglutinin-activated lymphocytes that had been expanded in vitro in IL-2-containing medium could be efficiently targeted against hepatoma cells. Targeting by DQ-33 bimAb was analyzed on different subsets of IL-2-cultured lymphocytes. It was evident that CD+4-8+ TCRα/β+ and CD3+4-8-TCRγ/δ+ lymphocytes were efficiently induced by bimAb to lyse human hepatoma cells, whereas no induction of cytolysis could be observed when CD3+4+8-TCRα/β+ cells were used as effectors. DQ-33 bimAb was also able to induce lymphokine secretion (IL-2, GM-CSF and TNFα) by all the differet subsets of lymphocytes analyzed in the presence of target cells expressing the relevant antigen, independent of the expression of cytolytic activity.
|Number of pages||8|
|Publication status||Published - 1992|
ASJC Scopus subject areas
- Cancer Research