RESUMEN
Objective:To investigate the possibility of producing vaccine with higher effect of anti-hepatoma by means of freezing the tumour cells which have been modified by TNF-? genes before. Methods: H22 cells which had been modified by TNF-? genes were treated by means of freezing and 60Co radiation or of 60Co radiation, respectively. Then, they were put to use to produce two kinds of vaccines. Effects of these two kinds of vaccines on anti- plant-hepatoma in mice were compared. Results: Effects of increasing the inhibiting rates, the levels of lectin-induced IL-2 and TNF from splenocytes, and the splentic NK activity, were all obviously seen stronger in vaccine made up of cells treated by the method combined with freezing, than that in vaccine made up of cells by no freezing. Conclusion: Method of freezing, after procedure of TNF-a gene modifying, could raise up the immunogenicity of the tumour cells, thereby enhance the anti-plant-hepatoma effect in mice induced by the vaccine.