An isolated or recombinant aminopeptidase N (pepN) polypeptide having inflammatory cytokine production and cytolysis inhibiting activity is provided. A method of inhibiting inflammatory cytokine production and cytolysis in a subject in need thereof is also provided, comprising administering to the subject an inflammatory cytokine production and cytolysis inhibiting amount of the isolated or recombinant pneumococcal pepN polypeptide. A method of treating a disease, disorder, or condition characterized by or associated with undesirable inflammatory cytokine production and cytolysis in a subject in need thereof is also provided, comprising administering to the subject a therapeutically effective amount of an isolated or recombinant pepN polypeptide. A method of treating pneumococcal infection in a subject in need thereof is also provided comprising administering to the subject a therapeutically effective amount of an anti-pepN polypeptide inhibitory agent.