Impaired IgA class switching in APRIL-deficient mice.

Proc Natl Acad Sci U S A

Division of Immunology, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.

Published: March 2004

The tumor necrosis factor (TNF) family member APRIL binds to the receptors BCMA on B cells and TACI on B and T cells. To investigate the role of APRIL in immunity, we generated APRIL-deficient mice. APRIL(-/-) mice have normal T and B lymphocyte development, normal T and B cell proliferation in vitro, but increased numbers of CD44(hi)CD62L(lo) CD4(+) effector/memory T cells and increased IgG responses to T-dependent antigens. Serum IgA levels were significantly decreased, and serum IgA antibody responses to mucosal immunization with TD antigens and to type 1 T-independent antigens were impaired in APRIL(-/-) mice. APRIL by itself induced IgA as well as IgG1 isotype switching in CD40-deficient IgM(+)IgD(+) sorted B cells. These results suggest that APRIL down-regulates T cell-dependent antibody responses and promotes IgA class switching.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC374342PMC
http://dx.doi.org/10.1073/pnas.0307348101DOI Listing

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