[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.


CONCLUSIONS
C3 defect results in impaired DTH responses in mice, which indicates the important role of C3 in DTH reaction.
Qiu
Yi-gang
YG
Department of Immunology, Southern Medical University, Guangzhou 510515, China. qiuyg@fimmu.com
Chen
Yue
Y
Zhang
Li-yun
LY
Chen
Zheng-liang
ZL
D000818:Animals; D003176:Complement C3 / Q000172:deficiency / Q000276:immunology* / Q000502:physiology*; D005260:Female; D006968:Hypersensitivity, Delayed / Q000139:chemically induced / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010047:Ovalbumin
D003176:Complement C3; D010047:Ovalbumin