Immunocytochemical Labelling of Bacteroides nodosus Pili Using an Immunogold Technique

Abstract

An immunogold labeling technique was used to label the pili of B. nodosus. The labeling was distinct and highly specific; individual pili could be recognized beneath the gold probe. The labeling of somatic antigens could be distinguished from that of pilus antigens. Labeling of fragments of cytoplasm released by cell lysis and trapped in the pili could be distinguished from pilus labeling. An antiserum that was raised against strain 80200 (serotype N) labeled pili of strain 215 (serotype B). Double labeling experiments with this antiserum and the antiserum against strain 215 (serotype B) showed that both antisera label the same pili bundles. The ease of detection of the immunocytochemical reaction should enable this technique to be used as a routine screen for pilus antigens. It possesses the potential for much wider applications for immunolabeling other antigens, such as viruses, that can be obtained in suspension.