Exotoxins are noxious proteins secreted by many bacteria. These toxins are often heat-labile and thus can be heat-inactivated for use as vaccines to prevent toxigenic immunity to bacteria disease. Many bacteria produce more than one protein exotoxin, making vaccine development more difficult. (more…)

Streptococcus pneumoniae strains, commonly called pneumococci, differ from other streptococci in that they contain complex polysaccharide capsules that consitute the major virulence determinant in the species. Pneumococci are respiratory pathogens that colonize upper airways and cause bronchitis or pneumonia after aspiration of respiratory secretions. (more…)