Cytotoxicity for a bispecific single-chain antibody against T cells and ovarian carcinoma

Objective: To investigate the in vitro effect of bispecific single-chain antibody-mediated tumor cells killing by Jurkat cells and PBMC cells. Methods: Jurkat cells or PBMC cells of healthy individuals were co-cultured with rIL-2, anti-CD3 monoconal antibody(McAb) and anti-CD28 scFv (VH). SKOV3 target cells and different values of scBsAb were plated in wells of the 96-well flat-bottom plates and incubated overnight. Effector cells were added into the tumor cell monolayers and plates were incubated for 4 h, 20 h, 24 h, 48 h and 72 h. Cytotoxic activity was evaluated by MTT assay. Results: (1) Cytotoxicity activities of effect cells stimulated by a certain values of rIL-2, anti-CD3 McAb and anti-CD28 scFv (VH) were stronger than those stimulated with scBsAb alone. (2) The results showed that under the existing of scBsAb, Jurkat cells and PBMC cells had the similar effect on tumor cells. The cytotoxicities were respectively up to 74.8% and 73.1%. (3) The cytotoxic activities relied on the values of scBsAb, time, and the ratio of effect cells to the tumor cells. For Jurkat cells, 21μg/ml scBsAb, 48 h and E/T = 10:1 would be proper, the cytotoxicity was up to 74.8%; For PBMC cells, 20μg/ml scBsAb, 72 h and E/T = 1:1 would be an ideal condition, the cytotoxicity was up to 73.1%. (4) It was a good strategy of using combined cytokines. Conclusion: scBsAb would be a promising immunological tools for the elimination of tumor cells.