title: CD30 is required for CCL21 expression and CD4 T cell recruitment in the absence of lymphotoxin signals.
abstract: Lymphoid tissue inducer cells express a diverse array of tumor necrosis family ligands, including those that bind CD30 and the lymphotoxin beta receptor. Both of these signaling pathways have been linked with B/T segregation in the spleen. In this study, we have dissected a lymphotoxin-independent CD30-dependent signal for the induction of expression of the T zone chemokine, CCL21. Reduced expression of CCL21 due to CD30 deficiency was functionally significant: mice deficient in both lymphotoxin and CD30 (dKO) signals had significantly smaller accumulations of lymphocytes in their splenic white pulp areas, with no evidence of focal aggregation of T cells. Furthermore, recruitment of wild-type CD4 T cells was poor in dKO mice compared with both wild-type or lymphotoxin-deficient mice. Phylogeny suggests that CD30 signals predated those through the lymphotoxin beta receptor. We suggest that CD30 signals from lymphoid tissue inducer cells were a primitive mechanism to recruit and prime CD4 T cells. This would have been a stepping stone in the evolution of the highly organized lymphotoxin dependent B and T white pulp areas within which CD4-dependent memory Ab responses now develop.
authors.affiliation: La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA.
authors.forename: Vasileios
authors.initials: V
authors.lastname: Bekiaris
authors.forename: Fabrina
authors.initials: F
authors.lastname: Gaspal
authors.forename: Mi-Yeon
authors.initials: MY
authors.lastname: Kim
authors.forename: David R
authors.initials: DR
authors.lastname: Withers
authors.forename: Fiona M
authors.initials: FM
authors.lastname: McConnell
authors.forename: Graham
authors.initials: G
authors.lastname: Anderson
authors.forename: Peter J L
authors.initials: PJ
authors.lastname: Lane