Role of IP-10/CXCL10 in the progression of pancreatitis-like injury in mice after murine retroviral infection

Exocrinopathy and pancreatitis-like injury were developed in C57BL/6 (B6) mice infected with LP-BM5 murine leukemia virus, which is known to induce murine acquired immunodeficiency syndrome (MAIDS). The role of chemokines, especially CXCL10/interferon (IFN)-γ-inducible protein 10 (IP-10), a chemokine to attract CXCR3+T helper 1-type CD4+T cells, has not been investigated thoroughly in the pathogenesis of pancreatitis. B6 mice were inoculated intraperitoneally with LP-BM5 and then injected every week with either an antibody against IP-10 or a control antibody. Eight weeks after infection, we analyzed the effect of IP-10 neutralization. Anti-IP-10 antibody treatment did not change the generalized lymphadenopathy and hepatosplenomegaly of mice with MAIDS. The treatment significantly reduced the number of IP-10- and CXCR3-positive cells in the mesenteric lymph nodes (mLNs) but not the phenotypes and gross numbers of cells. In contrast, IP-10 neutralization reduced the number of mononuclear cells infiltrating into the pancreas. Anti-IP-10 antibody treatment did not change the numbers of IFN-γ+and IL10+cells in the mLN but significantly reduced their numbers, especially IFN-γ+and IL-10+CD4+T cells and IFN-γ+Mac-1+cells, in the pancreas. IP-10 neutralization ameliorated the pancreatic lesions of mice with MAIDS probably by blocking the cellular infiltration of CD4+T cells and IFN-γ+Mac-1+cells into the pancreas at least at 8 wk after infection, suggesting that IP-10 and these cells might play a key role in the development of chronic autoimmune pancreatitis.