<prompt> Febrile response in CNS is mediated by all exceptBacterial toxinIL-lIL-6Interferon  <response>: Fever is produced in response to substances called pyrogens that act by stimulating prostaglandin synthesis in the vascular and perivascular cells of hypothalamus.They can be classified as:Exogenous pyrogens - Endotoxin of gram - bacteria, superantigens gram bacteria.Endogenous pyrogens - IL-1, TNF-alpha, Ciliary neurotropic factor and IFN-alpha.PGE 2 is the most important chemical responsible for elevation of hypothalamic set point in the body.So, NSAIDs reduce fever by inhibiting cyclooxygenase and reducing prostaglandin concentration. 