Regulation of B7-H1 expression on peripheral monocytes and IFN-γ secretion in T lymphocytes by HBeAg

• HBeAg can significantly up-regulate B7-H1 on monocytes.
• HBeAg can significantly down-regulate TLR2 on monocytes.
• HBeAg can down-regulate IFN-γ secreted by CD3+CD4+ T lymphocytes.
• HBeAg can up-regulate Th2-type cytokines secreted by CD3+CD4+ T lymphocytes.
• HBeAg can suppress the specific cellular immunity.

This study is to observe the expression of B7-H1, PD-1 and TLR2 on peripheral blood monocytes (PBMCs) regulated by HBeAg in chronic hepatitis B (CHB), and to illustrate the relation between HBeAg and persistent infection of HBV. In both CHB patients and healthy controls, the expression of B7-H7 was significantly increased on CD14+ monocytes incubated with HBeAg, while that of TLR2 was significantly reduced; the expression of specific IFN-γ was significantly decreased in CD3+CD4+ T lymphocytes incubated with HBeAg, while IL-6 and IL-10 in conditioned media were significantly increased. HBeAg is able to significantly up-regulate B7-H1, down-regulate TLR2 on monocytes, reduce IFN-γ produced by T lymphocytes and increase Th2-type cytokines secretion. These findings suggest that HBeAg suppresses the specific cellular immunity to clear the virus, and eventually lead to immune tolerance to HBV infection. Therefore, HBeAg plays an important role in immune suppression in chronic HBV patients.