ABSTRACT
Objective: To study the therapeutic effect of secondary lymphoid tissue chemokine (SLC) combined with CpG oligodeoxynucleotide (CpG-ODN) in treatment of implanted mouse melanoma and the possible mechanism. Methods: SLC-Fc fusion protein was prepared and its chemotaxis of lymphocytes was detected by chemotaxis assay. Implanted melanoma mouse models were established and randomly divided into 4 groups: control group, SLC-Fc group, CpG-ODN group, and SLC-Fc+CpG-ODN group. The growth of implanted tumors in each group was observed after treatment. Subtype and infiltration of lymphocytes in implanted tumor tissues were examined by flow cytometry. Results: SLC-Fc protein was successfully prepared, and it dose-dependently attracted lymphocytes (0.03, 0.3, and 3 μg/L). Intra-tumor injection SLC-Fc and CpG-ODN alone or in combination significantly inhibited growth of B16-implanted tumors. Tumor size in SLC-Fc+CpG-ODN group was significantly smaller than that in control group (P<0.01), and animals in SLC-Fc+CpG-ODN group survived longer. Tumor-infiltrated CD4~+ T, CD~8+ T, and dendritic cells (DCs) in SLC-Fc+CpG-ODN group were markedly increased as compared with those in control group (P<0.05), and tumor draining lymph nodes were dramatically enlarged. Conclusion: SLC combined with CpG-ODN can inhibit the growth of implanted melanoma by attracting CD4~+ T and CD8~+ T and promoting proliferation of DCs.