Schaerli P Willimann K Lang AB Lipp M Loetscher P Moser B 2000 Leukocyte traffic through secondary lymphoid tissues is finely tuned by chemokines. We have studied the functional properties of a human T cell subset marked by the expression of CXC chemokine receptor 5 (CXCR5). Memory but not naive T cells from tonsils are CXCR5(+) and migrate in response to the B cell-attracting chemokine 1 (BCA-1), which is selectively expressed by reticular cells and blood vessels within B cell follicles. Tonsillar CXCR5(+) T cells do not respond to other chemokines present in secondary lymphoid tissues, including secondary lymphoid tissue chemokine (SLC), EBV-induced molecule 1 ligand chemokine (ELC), and stromal cell-derived factor 1 (SDF-1). The involvement of tonsillar CXCR5(+) T cells in humoral immune responses is suggested by their localization in the mantle and light zone germinal centers of B cell follicles and by the concomitant expression of activation and costimulatory markers, including CD69, HLA-DR, and inducible costimulator (ICOS). Peripheral blood CXCR5(+) T cells also belong to the CD4(+) memory T cell subset but, in contrast to tonsillar cells, are in a resting state and migrate weakly to chemokines. CXCR5(+) T cells are very inefficient in the production of cytokines but potently induce antibody production during coculture with B cells. These properties portray CXCR5(+) T cells as a distinct memory T cell subset with B cell helper function, designated here as follicular B helper T cells (T(FH)). application/pdf https://sonar.ch/global/documents/430 eng info:eu-repo/semantics/altIdentifier/doi/10.1084/jem.192.11.1553 info:eu-repo/semantics/altIdentifier/pmid/11104798 info:eu-repo/semantics/openAccess The Journal of experimental medicine. - 2000 Animals B-Lymphocytes Chemokine CCL19 Chemokine CCL21 Chemokine CXCL12 Chemokine CXCL13 Chemokines, CC Chemokines, CXC Chemotaxis, Leukocyte Cytokines Germinal Center Humans Immunoglobulin Isotypes Leukocyte Common Antigens Leukocytes, Mononuclear Lymphoid Tissue Palatine Tonsil Receptors, CCR7 Receptors, CXCR5 Receptors, Chemokine Receptors, Cytokine Receptors, Lymphocyte Homing T-Lymphocytes, Helper-Inducer CXC chemokine receptor 5 expression defines follicular homing T cells with B cell helper function. http://purl.org/coar/resource_type/c_6501