Intriguingly, although we found in vitro and histological evidence for mast cell activation upon S. pneumoniae exposure, we did not see any effect of mast cell deficiency (by using two different Kit mutant mouse strains) on the disease phenotype, bacterial outgrowth, and CNS inflammation (except for an increase in CSF pleocytosis) in an in vivo meningitis model. This evidence concerns the gene KIT and infectious meningitis.