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. Here, IL6 is linked to pneumococcal meningitis.