Antitumor Immunity Elicited by B7-1 Gene Transfected EL-4 Lymphoma inVIVO / 中国肿瘤生物治疗杂志

ABSTRACT

We have studied the effects of B7-1 on antitumor immunity induced in vivo by murine B7-1 gene transfected EL-4 lymphoma. At a lethal dose of wild - type(wt) or plasmid controlled (pc) B7-1 negative tumor cells. B7-1 gone transfected EL-4 cells inoculated in syngeneic mice were regressed. In contrast to the mice immunized with B7-1 tumor cells, immunization of mice with B7-l~EL-4 tumor cells showed significant protective effects against the sequence rechallenge of wt EL-4 tumor. Vaccination with X-irradiated B7-1 positive tumor cells at the early stage ( 7 days) after inoculation of wt EL-4 tumor cells showed some therapeutically effects but not at the late stage (14 days after inoculation). Vaccination with B7-l~+ EL-4 tumor cells delayed the occurrence of wt EL-4 tumors and prolonged the survival period of tumor-bearing mice. Our results indicate that the transfcction of B7-1 into tumor cells can increase the immunogenicity of EL-4 tumor and improve host response to wt EL-4 lymphoma. Immunization with B7-1 positive tumors can elicit effective antitumor immunity.