Objective   To investigate the effect of the expression level of dendritic-cell specific ICAM-3 grabbing non-integrin (DC-SIGN) which was regulated by IL-4 on the immune function of dentritic cells (DCs) and analyze the relationship between the expression level and tuberculosis.    Methods   IL-4 at different doses (5

10

50

100 and 200 ng/ml) was used to regulated the expression level of DC-SIGN in DCs. The DCs were divided into 2 groups according to the different doses of IL-4

which were 5 ng/ml group and 50 ng/ml group

and then were co-cultured with 100 ng/ml LPS or the suspension of Mycobacterium Tuberculosis H

37

Rv. The phenotypes (CD11c

DC-SIGN

CD83

CD86

and HLA-DR）of DCs were analyzed by flow cytometry. The concentrations of IL-12 and IL-10 in the DCs supernatant were measured by ELISA. The ability of DCs to stimulate T cell proliferation was detected by mixed leukocytes reaction (MLR).    Results   IL-4 regulated the expression level of DC-SIGN in a dose-dependent manner. When the dose of IL-4 was increased from 5 ng/ml to 50 ng/ml

the expression level of DC-SIGN was elevated obviously (P0.05). But when the dose was increased from 50 ng/ml to 200 ng/ml

the expression level also was risen

though with no statistical difference (P0.05). There was no significant difference in the maturity degree of DCs which had different expression levels of DC-SIGN (P0.05). No significant difference was observed in the concentrations of IL-12 in the supernatant of DCs with high (50 ng/ml IL-4) or low levels (5 ng/ml IL-4)  DC-SIGN expression in present of LPS or H

37

Rv (P0.05). When co-cultured with LPS

the DCs with different expression of DC-SIGN secreted similar amount of IL-10 (P0.05). But when co-cultured with H

37

Rv

the DCs with high expression level of DC-SIGN produced significantly more IL-10 than the

cells with low expression level (P0.05). After the treatment of LPS

the DCs with different expression level of DC-SIGN had the similar ability to stimulate allogenic T cell proliferation (P0.05). Compared with LPS

H

37

Rv treatment showed similar ability of DCs with high DC-SIGN expression to stimulate allogenic T cell proliferation (P0.05)

but for the DCs with low DC-SIGN expression

the ability was much lower than those of the other group did (P0.05).    Conclusion   DCs with high expression level of DC-SIGN secreted more IL-10 when co-cultured with H

37

Rv than the cells with low expression

but the later cells have lower ability to stimulate allogenic T cell proliferation. Expression of DC-SIGN no matter upregulated or downregulated has disadvantage to the outcome of the tuberculosis immunity.