Gram-positive bacteria: an overview and summary of session.
The more pathogenic gram-positive bacteria present a complex array of surface structures to the human or animal host. The cell wall of Staphylococcus aureus has a pattern of surface proteins; the predominant one is protein A. Virulent S. aureus strains may also produce polysaccharide capsules in vivo that impede opsonization and phagocytosis in the absence of anticapsular antibody. Coagulase-negative staphylococci commonly elaborate an exopolysaccharide slime that may promote adherence to plastic surfaces and interfere with host responses. Structure-function relationships for some antiphagocytic M proteins of group A streptococci are now well understood, and recombinant techniques offer the prospect of multivalent vaccines. The best known surface protein of group B streptococci is the c (Ibc) protein, which stimulates protective antibody in animals and may be an important virulence factor. Monoclonal antibodies to types Ib, II, and III group B streptococci have also confirmed the presence of multiple immunodeterminants on these antiphagocytic polysaccharides. A protein on the surface of pneumococci has been shown to induce protective antibody and to enhance pneumococcal virulence in mice, suggesting a potential alternative or adjunct to pneumococcal polysaccharide vaccines. Listeria also possess a variety of cell surface structures important in pathogenesis. Surface components are, therefore, critical determinants of the interaction of gram-positive bacteria with the host.
Anthony
B F
BF
Department of Pediatrics, Harbor-UCLA Medical Center, Torrance 90509.
Hill
H R
HR
D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000032:analysis; D006094:Gram-Positive Bacteria / Q000032:analysis / Q000472:pathogenicity* / Q000648:ultrastructure; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D014774:Virulence
D001426:Bacterial Proteins; D008565:Membrane Proteins