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[Killing effect of Photofrin-Herceptin immunoconjugate on tumor cell lines in vitro].

OBJECTIVE
To study the specific killing effect of the Photofrin-Herceptin immunoconjugate on the tumor cells expressing HER-2.


METHODS
Photofrin (porfimer sodium) was covalently coupled to Herceptin (trastuzumab) via [1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimide hydrochloride](EDCI) , and the killing effect of this conjugate was evaluated by means of MTT assay on SK-BR-3, MCF-7 and A549 cell lines expressing HER-2 at different levels.


RESULTS
The conjugate had weaker immunoactivity than Herceptin, but possessed stronger killing effect on the cell lines expressing HER-2 than Photofrin, Herceptin, as well as the mixture of Photofrin and Herceptin (P<0.05). In the cell lines negative for HER-2 expression, the killing effect of the conjugate was similar to that of Photofrin, Herceptin, and their mixture.


CONCLUSION
Photofrin-Herceptin immunoconjugate can specifically kill HER-positive cells in vitro.