Anti-HER-2×anti-CD3 Bi-specific Antibodies Inhibit Growth of HCT-116 Colorectal Carcinoma Cells in Vitro and in Vivo

Objective: This study is conducted to evaluate the effects of anti-HER-2×anti-CD3 bi-specific antibodies(BsAb)on HER-2/neuover-expressing human colorectal carcinoma cells.
Methods: Growth was assessed by MTT assaysafter exposure of HCT-116 cells to Herceptin, anti-CD3 and BsAb antibodies. Immunocytochemistry was appliedto test the HER-2 level of HCT-116. In a nude mouse model, HER-2×CD3 BsAb was combined with effectorcells (peripheral blood lymph cells from normal human being) for observations on in Vivo growth of tumors.
Results: Compared with the control group, using effector cells combined with anti-CD3 McAb, Herceptin orHER2×CD3 BsAb, tumor cell growth in vitro and in vivo was significantly inhibited (P<0.05), most remarkablyin the HER2×CD3 BsAb case. The growth of xenografts with HER2×CD3 BsAb combined with effector cells wasalso significantly inhibited when compared with the anti-CD3 McAb or Herceptin groups (P<0.05).
Conclusion:HER-2/neu might be a useful target for immunotherapy in colorectal carcinoma, anti-HER2×anti-CD3 BsAbexerting clear anti-tumor effects.