ANTIBODY TARGETING TO BACTERIAL-CELLS USING RECEPTOR-SPECIFIC LIGANDS

The binding of antibodies to bacterial cells is necessary to effect host defense mechanisms such as complement activation and macrophage recognition. We have designed a biotinylated C-glycoside of mannose (BCM) that, when complexed with avidin, targets antibodies to a pathogenic strain of Escherichia coli containing type 1 pili mannose-specific receptors. Antibody binding to the bacterial cells was viewed by transmission electron microscopy using a protein A gold label. Antibody binding occurs only in the presence of the BCM-avidin conjugate and can be titrated off the surface of the cell by methyl alpha-D-mannopyranoside, demonstrating that antibody binding is mediated by the receptor. The conserved binding domain of cell-surface lectins can therefore be utilized to direct antibodies to pathogens.