Exogenous

One model for the method of fever down to exogenous pyrogens includes LPS, which is a cell wall component of gram-negative bacteria. An immunological protein called lipopolysaccharide-binding protein (LBP) binds to LPS. The LBP–LPS complex then binds to the CD14 receptor of a close by macrophage. This binding results synthesis and release of different endogenous cytokine factors like interleukin 1 (IL-1), interleukin 6 (IL-6) and the tumor necrosis factor-alpha. In other words, exogenous factors reason release of endogenous factors, which, in turn, make active the arachidonic acid pathway.