The Journal of immunology : official journal of the American Association of Immunologists
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Multiple sclerosis is an immune-mediated demyelinating disease of unknown etiology that presents with either a chronic-progressive or relapsing-remitting clinical course. Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD) and relapsing-remitting experimental autoimmune encephalomyelitis (R-EAE) in the SJL/J mouse are both relevant murine CD4+ T cell-mediated demyelinating models that recapitulate the multiple sclerosis disease phenotypes. To determine the cellular and molecular basis for these observed differences in clinical course, we quantitatively analyzed the temporal expression of pro- and antiinflammatory cytokine mRNA expression in the central nervous system (CNS) and the phenotype of the inflammatory mononuclear infiltrates. ⋯ This pattern correlated with dynamic changes in the CD4+ T cell and F4/80+ macrophage populations during relapsing-remitting disease progression. Interestingly, IL-4 message was undetectable until disease remission(s), demonstrating its potential role in the intrinsic regulation of ongoing disease, whereas IL-10 was continuously expressed, arguing against a regulatory role in either disease. These data suggest that the kinetics of cytokine expression together with the nature of the persistent inflammatory infiltrates are major contributors to the differences in clinical course between TMEV-IDD and R-EAE.
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X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disease caused by mutations of Bruton tyrosine kinase (Btk); Btk plays an essential role in the development of mature B cells. However, small numbers of B cells ("leaky B cells") are present in the peripheral blood of most XLA patients. In this study, we analyzed the function of these leaky B cells obtained from XLA patients. ⋯ In addition, three of the five XLA patients studied were immunized with bacteriophage phiX174 and produced low but detectable levels of antiphage-specific Ab. Similarly, X-linked immunodeficiency mice, which carry a missense mutation in Btk, produced substantial amounts of antiphage Ab. These results indicate that CD40 signaling is intact in B cells lacking demonstrable Btk, and that leaky B cells in XLA patients can proliferate, undergo isotype switching, and differentiate into specific Ab-producing cells.
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The involvement of granulocyte-macrophage CSF (GM-CSF) in collagen-induced arthritis (CIA) was examined using GM-CSF-deficient mice. Although CIA is generally considered to be restricted to mice of the H-2q or H-2r haplotypes, we examined the role of GM-CSF in the CIA model using GM-CSF-deficient (-/-) and wild-type (+/+) mice on a C57BL/6 (H-2b) background. Mice were immunized by intradermal injection at the base of the tail with chick type II collagen followed by a repeat injection 21 days later. ⋯ GM-CSF(+/+) and GM-CSF(+/-) mice exhibited CIA responses ranging from mild (single digits) to severe swelling of all four paws, while in the few GM-CSF(-/-) mice that developed CIA the disease was confined to single digits. Despite the putative role of GM-CSF in dendritic cell development, GM-CSF-deficient mice exhibited both humoral and cellular (delayed-type hypersensitivity) responses to type II collagen; however, the cellular response was significantly reduced in the GM-CSF-deficient mice compared with the wild-type controls. These findings suggest that GM-CSF is required for CIA development in mice and support the idea that GM-CSF is a key cytokine in inflammatory joint disease.