C3在迟发型超敏反应中的作用

目的 探讨补体成分3（C3）在迟发型超敏反应（DTH）中的作用。方法用卵白蛋白（OVA）诱导C3基因敲除（C3^-/-）和野生型（C3^＋/＋）小鼠足垫部位的DTH，测量足垫厚度的变化，并对反应部位组织进行HE和免疫组化染色检测。分离小鼠脾脏T淋巴细胞，用巨噬细胞作为抗原提呈细胞，在体外分别用丝裂原和特异性抗原刺激，用^3H-TdR掺入法评价T淋巴细胞的增殖活性。结果OVA诱导足垫DTH后，C3^-/-小鼠足垫厚度和局部浸润单个核细胞的数量都显著低于C3^＋/＋小鼠的，其中浸润的单个核细胞主要为CD4^＋T淋巴细胞。2种小鼠的T淋巴细胞对丝裂原刺激的反应相似，而已致敏C3^-/-小鼠脾脏T细胞对特异性抗原再次刺激后的增殖反应显著低于C3^＋/＋小鼠。结论C3缺陷明显影响DTH应答，提示C3在DTH中起了重要作用.

Role of complement C3 in delayed-type hypersensitivity

OBJECTIVE: To explore the role of complement C3 in delayed-type hypersensitivity (DTH). METHODS: After inducing DTH reaction in the footpads of C3 knockout C3(-/-) and wild-type (C3(+/+) ) mice with ovalbumin (OVA), the thickness of the footpad was measured and HE and immunohistochemical staining preformed to identify the number and types of the infiltrating mononuclear cells in the footpad tissues. T lymphocytes were separated from the spleens of the mice and incubated in 96-well plates with serial dilutions of OVA or mitogens in the presence of mitomycin C-treated macrophages, and the proliferation of the T cells was assessed by (3)H-TdR incorporation assay. RESULTS: The footpad thickness of DTH-C3(-/-) mice was significantly smaller than that of DTH-C3(+/+) mice. The number of the infiltrating mononuclear cells in the footpad tissue of C3(-/-) mice was obviously decreased in comparison with that of C3(+/+) mice, and the cells were characterized mainly as CD4(+) T lymphocytes. No significant difference in the proliferation of mitogen-stimulated splenic T cells was noted between C3(-/-) and C3(+/+) mice, but after stimulation with the specific antigen OVA, significant reduction in the proliferation of splenic T cells from C3(-/-) mice was observed as compared with the T cell proliferation in C3(+/+) mice. CONCLUSION: C3 defect results in impaired DTH responses in mice, which indicates the important role of C3 in DTH reaction.