Fig. 1.

CD14 is a macrophase receptor for rhamnose containing BclA. (A) Identification of CD14 as a macrophage receptor for B. anthracis spores. (a) Biotin-labeled spore-bound proteins, derived from lysed Raw 264.7 cells, were resolved on SDS/PAGE, and transferred to PVDF membranes. Proteins were detected by Western blot with HRP-streptavidin A, Coomasie blue staining (B) and anti-CD14 antibody (C). (D) BMDM from C57BL/6 or CD14^−/− mice were surface biotinylated and biotinylated proteins were pull down with spores. Spore bound proteins were detected by Western blot with anti-CD14 antibody. (B) Rhamnose residues associated with spore exosporium bind to CD14. Wt, ΔrmlD, ΔdegT and ΔbclA spores were incubated with different concentrations of biotinylated CD14. The binding of CD14 to spores was determined by flow cytometry after staining with streptavidin-APC.