Unique and conserved functions of B cell-activating factor of the TNF family (BAFF) in the chicken.
The chicken represents the best-characterized animal model for B cell development in the so-called gut-associated lymphoid tissue (GALT) and the molecular processes leading to B cell receptor diversification in this species are well investigated. However, the mechanisms regulating B cell development and homeostasis in GALT species are largely unknown. Here we investigate the role played by the avian homologue of B cell-activating factor of the tumor necrosis factor family (BAFF). Flow cytometric analysis showed that the receptor for chicken B cell-activating factor of the tumor necrosis factor family (chBAFF) is expressed by mature and immature B cells. Unlike murine and human BAFF, chBAFF is primarily produced by B cells both in peripheral lymphoid organs and in the bursa of Fabricius, the chicken's unique primary lymphoid organ. In vitro and in vivo studies revealed that chBAFF is required for mature B cell survival. In addition, in vivo neutralization with a decoy receptor led to a reduction of the size and number of B cell follicles in the bursa, demonstrating that, in contrast to humans and mice, in chickens BAFF is also required for the development of immature B cells. Collectively, we show that chBAFF has phylogenetically conserved functions in mature B cell homeostasis but displays unique and thus far unknown properties in the regulation of B cell development in birds.
Kothlow
Sonja
S
Institut für Tierphysiologie, University of Munich, Veterinärstrasse 13, D-80539 Munich, Germany.
Morgenroth
Iris
I
Graef
Yvonne
Y
Schneider
Kirsten
K
Riehl
Ingrid
I
Staeheli
Peter
P
Schneider
Pascal
P
Kaspers
Bernd
B
D000818:Animals; D053264:B-Cell Activating Factor / Q000276:immunology / Q000378:metabolism*; D053265:B-Cell Activation Factor Receptor / Q000276:immunology / Q000378:metabolism; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D015152:Blotting, Northern; D002454:Cell Differentiation / Q000276:immunology; D002642:Chick Embryo; D002645:Chickens; D005434:Flow Cytometry; D006801:Humans; D017403:In Situ Hybridization; D008221:Lymphoid Tissue / Q000166:cytology / Q000254:growth & development* / Q000276:immunology*; D010802:Phylogeny
D053264:B-Cell Activating Factor; D053265:B-Cell Activation Factor Receptor