title: Accessibility of enterobacterial common antigen to antibodies in encapsulated and non-capsulated S and R forms of Escherichia coli.
abstract: Antiserum specific for the enterobacterial 'common antigen' (ECA) was obtained by absorbing a rabbit ECA antiserum with an ECA-negative mutant. Accessibility of ECA to antibodies in encapsulated and non-capsulated S and R forms derived from Escherichia coli O8:K27 was studied using the indirect immunoferritin technique (whole-mount electron microscopy). The number of ferritin particles on the bacterial surface decreased in the order, non-capsulated R greater than encapsulated R greater than on-capsulated S greater than encapsulated S form, indicating that both the O and K antigens partly cover ECA on the surface of the outer membrane. Whole-mount and thin-section electron microscopy showed that ferritin was evenly distributed on the surface of R mutants, whereas it formed clusters on the S forms.
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology; D000942:Antigens, Bacterial / Q000032:analysis*; D002462:Cell Membrane / Q000276:immunology / Q000648:ultrastructure; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology* / Q000648:ultrastructure; D005293:Ferritins / Q000276:immunology; D007106:Immune Sera / Q000276:immunology; D008854:Microscopy, Electron; D009154:Mutation
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007106:Immune Sera; C017286:enterobacterial common antigen; D005293:Ferritins