title: Serotypes of sex pili.
abstract: There are situations in which direct observation of the attachment of antibody molecules may be the simplest method of detecting antigen-antibody reactions. Applied to the study of the sex pili determined by a number of transmissible bacterial plasmids, the method has distinguished four serotypes in the F-like class and two in the I-like class. Antibody was usually attached haphazardly to the pili; however, in a few cases a regular periodicity could be observed. When few antibody molecules were attached, they could frequently be individually resolved and in certain antibody-pilus combinations large antibody molecules, tentatively identified as IgM, could be seen to predominate.
mesh_terms: D000818:Animals; D000906:Antibodies / Q000032:analysis; D000937:Antigen-Antibody Reactions; D001665:Binding Sites; D004926:Escherichia coli / Q000166:cytology; D005111:Extrachromosomal Inheritance; D005827:Genetics, Microbial; D007075:Immunoglobulin M / Q000032:analysis; D007136:Immunoglobulins / Q000032:analysis; D008854:Microscopy, Electron; D011817:Rabbits; D012703:Serotyping
chemical_list: D000906:Antibodies; D007075:Immunoglobulin M; D007136:Immunoglobulins