title: Ultrastructural localization of capsules, cell wall polysaccharide, cell wall proteins, and F antigen in pneumococci.
abstract: The localization of pneumococcal capsular and cell wall antigens was examined by immunoelectron microscopy. C polysaccharide (C-Ps), a common component of all pneumococci, was uniformly distributed on both the inside and outside of the cell walls. The thickness of the C-Ps varied with the strain. Encapsulated strains were covered by varied amounts of capsular polysaccharide concealing the C-Ps of the bacteria so as to render it inaccessible to anti-C-Ps antibodies. In addition to C-Ps, protein antigens were demonstrable on the surface of nonencapsulated pneumococci. The proteins were not masked by the C-Ps layer. An extra layer on the cell walls was conspicuous on electron micrographs of both rough and encapsulated pneumococci. The nature of this extra layer has not been disclosed. F antigen, another common antigen of pneumococci, was uniformly distributed on the surface of the plasma membranes. During the course of the experimental work a reproducible method of gold labeling immunoglobulins was developed.
authors.affiliation: World Health Organization Collaborating Centre for Reference and Research on Pneumococci, Statens Seruminstitut, Copenhagen, Denmark.
authors.forename: U B
authors.initials: UB
authors.lastname: Skov Sørensen
authors.forename: J
authors.initials: J
authors.lastname: Blom
authors.forename: A
authors.initials: A
authors.lastname: Birch-Andersen
authors.forename: J
authors.initials: J
authors.lastname: Henrichsen
mesh_terms: D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000032:analysis*; D002473:Cell Wall / Q000648:ultrastructure; D006046:Gold; D007123:Immunoelectrophoresis, Two-Dimensional; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D011135:Polysaccharides, Bacterial / Q000032:analysis; D011506:Proteins / Q000032:analysis; D013296:Streptococcus pneumoniae / Q000276:immunology / Q000648:ultrastructure*
chemical_list: D000942:Antigens, Bacterial; D011135:Polysaccharides, Bacterial; D011506:Proteins; D006046:Gold