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Human B Cells Become Highly Responsive to Macrophage-Inflammatory Protein-3α/CC Chemokine Ligand-20 After Cellular Activation Without Changes in CCR6 Expression or Ligand Binding

2002; American Association of Immunologists; Volume: 168; Issue: 10 Linguagem: Inglês

10.4049/jimmunol.168.10.4871

1550-6606

Fang Liao, Aiko‐Konno Shirakawa, John F. Foley, Ronald L. Rabin, Joshua Μ. Farber,

Immunotherapy and Immune Responses

CCR6 is the only known receptor for the chemokine macrophage-inflammatory protein (MIP)-3alpha/CC chemokine ligand (CCL)20. We have shown previously that CCR6 is expressed on peripheral blood B cells, but CCR6 activity on these cells is low in in vitro assays. We report that MIP-3alpha/CCL20-induced calcium flux and chemotaxis can be enhanced significantly on peripheral blood and tonsillar B cells after activation by cross-linking surface Ag receptors. Of particular interest is the fact that the enhanced activity on B cells was not associated with an increase in CCR6 expression as assessed by levels of receptor mRNA, surface staining, or MIP-3alpha/CCL20 binding sites, or by a change in the affinity of the receptor for ligand. These data convincingly demonstrate that responses to a chemokine can be regulated solely by changes in the downstream pathways for signal transduction resulting from Ag receptor activation, and establish CCR6 as an efficacious receptor on human B cells.