title: Protection against bacteremic pneumococcal infection by antibody to pneumolysin.
abstract: Pneumolysin is an important virulence factor of Streptococcus pneumoniae. This study examined the hypothesis that human antibody to pneumolysin provides protection against pneumococcal infection. At the time of hospital admission, patients with nonbacteremic pneumococcal pneumonia had higher levels of serum anti-pneumolysin IgG than did patients with bacteremic pneumococcal pneumonia or uninfected control subjects. IgG levels rose significantly during convalescence in patients with bacteremic pneumonia, reaching levels observed in nonbacteremic patients. Purified human anti-pneumolysin IgG protected mice against intraperitoneal challenge with S. pneumoniae types 1 or 4 in a dose-related fashion; mice that received anti-pneumolysin IgG had a greater likelihood of surviving challenge and had negative blood cultures. Pneumolysin damages epithelial cells and inhibits phagocytic function of polymorphonuclear leukocytes. One hypothesis that might explain the study results is that, early in infection, IgG to pneumolysin blocks these effects in the alveoli, thereby protecting the host against bacteremic pneumococcal disease.
authors.affiliation: Medical Service, Infectious Disease Section, Houston Department of Veterans Affairs Medical Center, Houston, TX 77030, USA. daniel.musher@med.va.gov
authors.forename: D M
authors.initials: DM
authors.lastname: Musher
authors.forename: H M
authors.initials: HM
authors.lastname: Phan
authors.forename: R E
authors.initials: RE
authors.lastname: Baughn
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D016470:Bacteremia / Q000276:immunology / Q000517:prevention & control*; D001426:Bacterial Proteins; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000276:immunology; D008297:Male; D051379:Mice; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000517:prevention & control*; D011135:Polysaccharides, Bacterial / Q000276:immunology; D013301:Streptolysins / Q000276:immunology*; D013997:Time Factors; D014774:Virulence
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D011135:Polysaccharides, Bacterial; D013301:Streptolysins; C032290:plY protein, Streptococcus pneumoniae