Antitumor Efficacy Of Tumor Ell Vaccine Based On BLC

Chemokines are small molecule proteins that are the main mediators of cell migration. Studies indicated that chemokines could induce antitumor immune response strongly and steadily. Chemokine CXCL13 (CXC chemokine ligand 13), also known as BCA-1 (B cell-attracting chemokine 1) or BLC (B-lymphocyte chemoattractant), belonging to the CXC chemokine family , is the only chemokine that is known as chemoattract B cells through the interaction with its receptor (CXCR5). BLC is strongly expressed in the follicles of Peyer's patches, the spleen and lymph nodes. At present, there was not antitumor therapy about chemokine BLC. We hypothesized that ectopic expression BLC could be a cause for activation of B and T cells through cell trafficking and localization in the site of tumor and could be more effective in inhibiting tumor growth. In this study, we transfected pcDNA-BLC into murine tumor cell lines and established stable transfected tumor cell lines: CT26 and LL/2 to expressing BLC. We explored the generation of antitumor immune by inoculating tumor cells modified by BLC gene in animal tumor models. It was meant to explore the anti-tumor effects and mechanisms of BLC-modified tumor cell vaccine.Firstly the BLC full-length cDNA was amplified by RT-PCR from the total RNA isolated from the spleen of mouse. After sequence determination, the BLC full-length cDNA was cloned into the eukaryote expression vector pcDNA3.1 (+), the resulted recombinants was designated pcDNA-BLC. Then pcDNA-BLC was transfected into murine tumor cell line CT26 or LL/2 cells by LIPOFECTIN (Gibco Brl). The stable transformants were selected by G418 and identified by immunoblot assay and RT-PCR. The bioactivity of BLC was confirmed by Chemotaxis Assay. For the purpose of comparison, null plasmid pcDNA3.1(+) was also transfected into CT26 or LL/2 cells stably. We established mouse model with pcDNA-BLC stable transfected tumor cells(Tc), as control mouse model with pcDNA3.1(+) stable transfected tumor cells(Pc) and another with parental tumor cells(Nc). CT26 colon carcinoma models were established in BALB/c mice, and LL/2 models were established in C57BL/6 mice. We found that the tumor cell vaccines based on BLC had the highest rejection rate compared with other transfectants and also was effective at protective antitumor immunity in these two tumor models in mice, In the present study, it was shown that the modified tumor cells became highly immunogenic and was capable of inducing strong systemic immunity. Lymphocytes were dramatically increased in the tumor tissue. There was the deposition of IgG on the tumor cells. IgG subclasses were substantially increased in response to tumor cells. The antitumor activity and production of the autoantibodies could be abrogated by the depletion of CD4 T lymphocytes. The influx of immune cells in tumor tissue was probably due to BLC from the modified tumor cells. By gene transfectant of BLC into tumor cells, the balance ofchemokine was breached.Taken together; we tested this concept that the chemokine BLC could induce antitumorimmunity. These findings may provide a new vaccine strategy for the treatment of tumors through the induction of the autoimmune response, and may be of importance to the further exploration of the role in the breaking of homeostatic chemokines self for cancer therapy.