TNF and pneumococcal meningitis: TNF, IL-6 and IL-1β are well-known markers of sickness behaviour during inflammation42 and their effect can potentially be long-lasting43, so it is likely that reduced IL-1β production due to TLR2/4 deficiency during the acute stage of pneumococcal meningitis is associated with amelioration of the hyperactive phenotype in PM mice that survived pneumococcal meningitis due to CEFT treatment.