Developmental stage-dependent collaboration between the TNF receptor-associated factor 6 and lymphotoxin pathways for B cell follicle organization in secondary …

J Qin, H Konno, D Ohshima, H Yanai… - The Journal of …, 2007 - journals.aai.org
J Qin, H Konno, D Ohshima, H Yanai, H Motegi, Y Shimo, F Hirota, M Matsumoto, S Takaki…
The Journal of Immunology, 2007journals.aai.org
Signal transduction pathways regulating NF-κB activation essential for microenvironment
formation in secondary lymphoid organs remain to be determined. We investigated the effect
of a deficiency of TNFR-associated factor 6 (TRAF6), which activates the classical NF-κB
pathway, in splenic microenvironment formation. Two-week-old TRAF6-deficient mice
showed severe defects in B cell follicle and marginal zone formation, similar to mutant mice
defective in lymphotoxin (Lt) β receptor (LtβR) signal induction of nonclassical NF-κB …
Abstract
Signal transduction pathways regulating NF-κB activation essential for microenvironment formation in secondary lymphoid organs remain to be determined. We investigated the effect of a deficiency of TNFR-associated factor 6 (TRAF6), which activates the classical NF-κB pathway, in splenic microenvironment formation. Two-week-old TRAF6-deficient mice showed severe defects in B cell follicle and marginal zone formation, similar to mutant mice defective in lymphotoxin (Lt) β receptor (LtβR) signal induction of nonclassical NF-κB activation. However, analysis revealed a TRAF6 role in architecture formation distinct from its role in the early neonatal Lt signaling pathway. LtβR signal was essential for primary B cell cluster formation with initial differentiation of follicular dendritic cells (FDCs) in neonatal mice. In contrast, TRAF6 was dispensable for progression to this stage but was required for converting B cell clusters to B cell follicles and maintaining FDCs through to later stages. Fetal liver transfer experiments suggested that TRAF6 in radiation-resistant cells is responsible for follicle formation. Despite FDC-specific surface marker expression, FDCs in neonatal TRAF6-deficient mice had lost the capability to express CXCL13. These data suggest that developmentally regulated activation of TRAF6 in FDCs is required for inducing CXCL13 expression to maintain B cell follicles.
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