THE LIMITED ROLE OF PNEUMOLYSIN IN THE PATHOGENESIS OF PNEUMOCOCCAL MENINGITIS

The aim of this study was to determine the role of pneumolysin, an int racellular toxin of Streptococcus pneumoniae, in the pathogenesis of p neumococcal meningitis. Recombinant pneumolysin (1 mu g), when injecte d intracisternally into rabbits, resulted in a brisk inflammatory resp onse. However, a pneumolysin-deficient strain of S. pneumoniae caused meningeal inflammation in rabbits indistinguishable from that induced by the parent pneumolysin-producing strain. Furthermore, similar enhan cement of meningeal inflammation occurred after ampicillin therapy in animals infected with either the parent strain or the pneumolysin-defi cient mutant. These results suggest that although pneumolysin can stim ulate the inflammatory cascade in the central nervous system, it is no t necessary for the pathogenesis of meningeal inflammation nor does it play a role in postantibiotic enhancement of meningeal inflammation.