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Role of BAFF/APRIL in GALT Development
Author(s) -
Yeramilli Venkata A.,
Knight Katherine L.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.842.7
Subject(s) - b cell activating factor , biology , b cell , autocrine signalling , immunoglobulin class switching , bone marrow , antibody , microbiology and biotechnology , splenocyte , naive b cell , immunology , receptor , t cell , antigen presenting cell , immune system , genetics
In rabbits, B cells develop in the bone marrow and migrate to GALT where they proliferate, form organized follicles, and develop the primary antibody repertoire by Ig gene diversification. While the molecular events leading to Ig gene rearrangements in the bone marrow are well understood, little is known about the mechanisms regulating B cell proliferation and homeostasis in GALT. We investigated the role(s) played by BAFF and APRIL in stimulating GALT B cells. By in situ hybridization, we found BAFF transcripts in the appendix to be highly expressed in B cell follicles. In striking contrast to human B cells, we detected BAFF expression on both naïve peripheral and GALT B cells. In vitro, purified rabbit BAFF induced splenocytes to undergo proliferation, but not B cells isolated from GALT. However, addition of BAFF to cultures of GALT B cells transiently prolonged their survival. Following in vivo injection of neonatal rabbits with a soluble decoy receptor (TACI‐Ig), we found a marked reduction in both the size and number of B cell follicles and also in Ki‐67 expression, demonstrating that BAFF/APRIL is required for B cell proliferation in GALT. We are currently investigating whether B cells residing in GALT are immature or mature B cells. Since rabbit B cells express BAFF, we propose that B cells in GALT are stimulated in an autocrine fashion. Supported by NIH AI50260