FIG. 3.

Identification of CD14 as the epithelial receptor for GXM in A549 cells. CD14-GXM complexes (triangles) from polysaccharide-treated cells were captured by IgM antibodies in ELISA. An anti-CD14 was used as the detection probe, as demonstrated in the schematic presentation of the capture ELISA (inset). No significant reactions with the anti-CD14 antibody were observed when protein extracts from untreated cells (inverted triangles) were used. Additional controls included an ELISA in which A549 lysates (positive control; squares) and protein extracts from Chinese hamster ovary cells (negative control; circles) were used to coat the plates, followed by sequential incubation with the anti-CD14 MAb and phosphatase-labeled secondary antibodies.