title: Polysaccharides of the genus Bacillus cross-reactive with the capsular polysaccharides of Diplococcus pneumoniae type 3, Haemophilus influenzae type b, and Neisseria meningitidis group A.
abstract: We studied 174 strains of the genus Bacillus for cross-reacting antigens to the capsular polysaccharides of groups A and C meningococcus, types I and III pneumococcus, and Haemophilus influenzae type b. Cross-reactions were detected by immunodiffusion in agarose gel by using type-specific antisera and confirmed by absorption and inhibition experiments. Of 20 Bacillus pumilis strains, six had an antigen cross-reacting with group A meningococcal polysaccharide. Other cross-reactions included one strain of B. pumilis with H. influenzae type b, one of B. cereus var. mycoides with pneumococcus type III, and one of B. alvei with both type b and SIII polysaccharides. These cross-reacting antigens are polysaccharides of vegetative cells and may be extracellular in location. Because these bacilli have antigens cross-reacting with the virulence factors of pyogenic bacteria, they may, as normal flora, be an antigenic stimulus for "natural" serum anti-capsular antibodies to the type b Haemophilus and group A meningococcus polysaccharides.
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis*; D001407:Bacillus / Q000276:immunology*; D001409:Bacillus cereus / Q000276:immunology; D003429:Cross Reactions; D006193:Haemophilus influenzae / Q000276:immunology* / Q000473:pathology; D005779:Immunodiffusion; D009345:Neisseria meningitidis / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000032:analysis*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000276:immunology*; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D011135:Polysaccharides, Bacterial