异种黑色素细胞疫苗诱导小鼠抗恶性黑色素瘤免疫反应的机理研究

The Mechanism of Anti-tumor Immue Response Against Mouse Melanoma to Xenogeneic Vaccination

目的 研究异种黑色素细胞疫苗诱导小鼠抗恶性黑色素瘤免疫反应的机理。方法 制备异种黑色素细胞疫苗 ,免疫小鼠。采用间接 EL ISA法检测小鼠抗肿瘤抗体滴度及抗体亚型 ,纯化免疫球蛋白及进行体外抗肿瘤增殖 ,采用 Western blot法分析交叉抗原蛋白质。接种恶性黑色素瘤 ,观察肿瘤生长 ,采用免疫细胞去除法分析NK细胞及 T细胞亚群对疫苗抑瘤效应的影响。结果 异种疫苗免疫后 2周小鼠体内出现抗自身肿瘤抗体 ,产生的抗体以 Ig G为主 ,抗体认别的猪眼黑色素细胞及恶性黑色素瘤细胞交叉抗原为相对分子质量达 180× 10 3的蛋白质 ,纯化的免疫球蛋白在体外能抑制恶性黑色素瘤细胞增殖。异种疫苗诱导特异性保护性免疫反应使 90 %小鼠恶性黑色素瘤生长受到抑制 ,去除 NK细胞不影响疫苗抑瘤效应 ,去除 CD4 + T细胞使疫苗抑瘤效应消失 ,去除CD8+ T细胞 70 %小鼠恶性黑色素瘤生长仍受到抑制。结论 异种黑色素细胞疫苗诱导特异性体液免疫及细胞免疫反应 ,抑制恶性黑色素瘤的生长 ,CD4 + T细胞在这一过程中发挥了关键性作用。

Objective To investigate the immunological mechanism for inhibiting melanoma growth in mouse by vaccination with xenogeneic melanocytes. Methods Xenogeneic vaccine was prepared from pig eye melanocytes. By meansed of indirect ELISA the antibodies against pig melanocytes and B16 melanoma cells in immunized mice sera were detected and the immunoglobulin subclass were analyzed. Then after purification, the immunoglobulins were used for the inhibition of cell proliferation in vitro. Analyses of cross-reactive antigen in both pig melanocytes and B16 melanoma cells were performed by Western blot. Xenogeneic vaccine was used before B16 melanoma challenge in C57 BL/c mice and then the growth of tumor was monitored. Meanwhile, other mice immunized with xenogeneic vaccine were depleted of NK cells or CD4+ or CD8+ T lymphocytes. Results The antibodies against pig melanocytes and B16 melanoma cells in mice sera were not detected by indirect ELISA until 2 weeks after first xenogeneic vaccination, and after the first finding, the antibody titers increased with the time of immunization. The anti-tumor activity and production of autoantibodies, conspicuously those of the elevated IgG, could be abrogated by the depletion of CD4+ T lymphocytes. The cross-reactive antigen with 180 kda protein in both pig melanocytes and B16 melanoma cells was confirmed. Xenogeneic vaccination resulted in inhibition of tumor growth in 90% of the immunized mice. The protective immune response elicited in this fashion was dispelled in the mice depleted of CD4+ T lymphocytes. However this response was found in 70% of the mice depleted of CD8+ T lymphocytes, and the depletion NK cells did not inflnence the anti-tumor effect of the vaccine. Conclusion The anti-tumor immune response is capable of inhibiting melanoma growth; both humoral immunity and cellular immunity could be induced by xenogeneic melanocytes vaccination. This immune response is mainly mediated by CD4+ T lymphocytes.