The aims of the current study were (1) to validate the beneficial effect of anti-C5 antibodies in a pneumococcal meningitis mouse model using a common pneumococcal serotype [1, 9] and (2) to assess the potential added benefit of combining anti-C5 antibody treatment with adjunctive dexamethasone in a randomized investigator-blinded trial. The gene discussed is C5; the disease is pneumococcal meningitis.