Prenentive And Therapeutic Efficacies Of Vaccination Of Rats With HSP70-enriched Glioma Cells

OBJECTIVE:The purpose of this study was to evaluate the efficacy of inactivated glioma cells with enriched HSP70 as vaccine to prevent the hosts from developing the homogenous tumor and to treat the hosts baring the homogenous tumor in an experimental animal model.METHODS:Implanting of live C6 glioma cells into right caudate nucleus with stereotactic technique and left armpit, respectively, were performed in SD rats to establish the cerebral and aubcutaneous glioma models. Beta-elemenetreated C6 cells ere incubated at 43 degree Celsius for 2h for the enrichment of HSP70 expression. On the basis of orthogonal design, the optima protocol covering dosage,number of doses and overall period of immunization for HSP70-enriched C6 cell vaccination was determined by MTT assays of splenic effector cell cytotoxicity against live C6 cells. A variety of C6 cell vaccines prepared by heat-shock procedure and/or the treatment of mitomycin C or beta-elemene, or their combinations, were assayed by flow cytometry for their HSP70 expression rates and injected into groups of SD rats prior to C6 cell challenge or after the formation of cerebral or subcutaneous glioma, respectively. The rate of glioma formation in combination with the length of survival was analyzed for the preventive effect of vaccines and the length of survival alone for therapeutic efficacy evaluation. The relation between the anti-tumor efficacy and the expression of HSP70 was also analyzed.RESULTS:Stable SD rat cerebral and subcutaneous glioma moedels were established. Immunization of the rats with HSP70-enriched C6 cell vaccines conferred protection of the hosts against the challenge of live C6 cells as indicated by the significant decrease of the rate of the formation of either cerebral of subcutaneous glioma(p<0.01) and the markedly prolonged survival of the animals which developed gliomas (p<0.01) . Vaccination of the twotumor-baring rat models with HSP70-enriched C6 cells resulted in the significant prolongation of the length of survival, too(p<0.01). The efficacies of protection in both preventive and therapeutic use of glioma vaccines were found to be closely associated with the levels of HSP70 enrichment ,and , to be remarkably diminished by the preincubation of HSP70-riched C6 cell vaccines with murine monoclonal anti-HSP70 antibodies (p<0.01) .CONCLUSIONS:Stereotactic technique is useful to the establishement of reliable cerebral glioma animal model without the metastasis of the tumor. Vaccination of HSPTO-enriched glioma cells is capable of conferring both preventive and therapeutic protections remarkably against the development of the homogenous neoplasm.