RESUMO
<p><b>OBJECTIVE</b>To investigate whether there is an association between the expression of B7-H1 in HBV transgenic mice and the immune tolerance to HBV.</p><p><b>METHODS</b>T cells stimulatory capacity of DC was analyzed using mixed lymphocyte reaction. Expression of MHC-II, CD80, CD86, B7-H1 on DC was detected by Flow Cytometry. IL-2, IFNgamma, IL-10 production of T cells were determined by using ELISA. B7-H1 mRNA and protein expression in liver tissue were detected by RT-PCR and Western blotting respectively.</p><p><b>RESULTS</b>The ability of DC cells from HBV transgenic mice to stimulate T cell proliferation was significantly impaired compared with DC cells from control mice (t = 16.674, 19.674, 21.712, P less than 0.01). Expression of MHC-II, CD80 on DC was markedly decreased in transgenic mice (t = 7.910, 6.413, P less than 0.05). Meanwhile, the expression of CD86 and B7-H1 on DC cells in HBV transgenic mice were not significantly different from that in control mice. The levels of IL-2, IFNgamma, IL-10 in supernatant of T cells was significantly lower compared with controls (t = 18.712, 18.712 and 11.683, P less than 0.05). There was no significant difference in B7-H1 expression at mRNA and protein levels in liver tissue compared with controls.</p><p><b>CONCLUSIONS</b>Functional defect of DC, partly due to decreased expression of MHC-II, CD80, but not related to B7-H1 expression, is the cause for immune tolerance to HBV in HBV transgenic mice.</p>