How RPT works

Schematic representation of the fever reaction in higher vertebrates, including in rabbits and humans. Microbial products (“exogenous pyrogens” enters the body (1) and bind to receptors for “common features of foreign”, so called TLRs on macrophages and monocytes (2). (Monocytes are precursor cells to macrophages, the latter being tissue resident, the former circulating in the blood). The Macrophages and monocytes become activated by the TLR stimulation (3) and respond with cytokine production: among the cytokines these cells produce is IL-6 (4) an "endogenous pyrogen". This IL-6 reaches the brain via the blood stream (5) and is perceived in the thermo regulation center (TRC) (6), being located in the pre-optic area of the hypothalamus. In response, the TRC raises the desired body temperature level, and fever results (7). The RPT measures the natural fever reaction of the body of the experimental animal, in vivo. MAT measures the initial steps, 2-4, in tissue culture, in vitro.