BLC B-lymphocyte chemoattractant [1,2] is a human CXC chemokine expressed in lymphoid tissues and which selectively attracts B lymphocytes via BLR1/CXCR5  (CXC chemokine receptor-5).
Gene-targeted mice (BLC-/- and CXCR5-/- mice) showed that BLC/BCA1 and its receptor CXCR5 are needed for B-cell homing to follicles in lymph nodes as well as in spleen .
BLC is required for the development of most lymph nodes and Peyer's patches. In addition to mediating chemoattraction, BLC induces B cells to upregulate membrane lymphotoxin α 1β 2, a cytokine that promotes follicular dendritic development and BLC expression .
In germinal centers, α 1β 2 expression is induced by a mechanism independent of BLC .