Chemokines and Receptors in Tfh Cell Differentiation and Function
Chemokines are a large superfamily of mostly small, secreted chemotactic cytokines that function in leukocyte migration, recruitment and activation. Trafficking of T cells through secondary lymph tissue during Tfh cell differentiation is controlled by the differential expression of chemokine receptors. Naïve T cells express CCR7. Binding of this receptor to CCL21 and CCL19 localizes naïve T cells to the T cell zone where they bind to the dendritic cells. The activated T cells then upregulate CXCR5, while decreasing CCR7 expression. Follicular stromal cells in the B cell follicle secrete CXCL13, the ligand for CXCR5, attracting the activated T cells to the follicle edge where they interact with antigen-primed B cells and differentiate into Tfh cells. Tfh cells continue to express high levels of CXCR5, which directs Tfh cells into the B cell follicle where they interact with centrocytes and aid in the formation of antibody-producing plasma cells and memory B cells. R&D Systems offers products for examination of chemokines and receptors in Tfh cell differentiation and function.