Studies on the Pathogenesis of Fever

Abstract

Polymorphonuclear leukocytes, when properly stimulated in vitro (1, 2), release an endogenous pyrogen that is believed to play a central role in the pathogenesis of fever (3,4). Demonstration that the release process is proroundly affected by factors involving electrolyte transport (2, 5) has suggested that the pyrogen may be derived from the membranes of the stimulated ceils (s).Previous studies on the nature of rabbit leukocytic pyrogen (6, 7) have revealed that it is: (a) nondialyzable, (b) relatively heat-labile, (c) precipitable with perchloric acid (HC104), (d) destroyed by phenol, (e) solublein 50 % methanol and 33 % saturated ammonium sulfate, (f) unaffected by butanol treatment, (g) inactivated by both diisopropyl fluorophosphate (DFP) and dinitrofluorobenzene (DNFB), and (h) rendered inert by trypsin and pepsin. These properties collectively indicate that it contains an essential protein.Approximately 50-fold purification of the crude pyrogen was first achieved by butanol treatment, removal of extraneous protein by methanol precipitation and anionic exchange chromatography (DEAE), and precipitation with ttCI04 (6). A later modification of the procedure (8) led to a further 4-fold purification and separated the activity of the pyrogen from that of lysozyme, an enzyme known to be released under the same conditions from polymorphonuclear leukocytes (2).Better methods of obtaining and purifying the pyrogen have since been devised, and further studies on its chemistry have been undertaken.

Studies on the Origin of Human Leukocytic Pyrogen

“…Chemical characterization of LP has shown it to be a protein molecule (6)(7)(8) and since the original discovery of its production by rabbit peritoneal exudate cells (9), many attempts have been made to determine the mechanism of its synthesis by leukocytes. With one exception (10), preformed pyrogen has not been obtained from disrupted rabbit cells (11,12).…”

Studies on the Pathogenesis of Fever

“…Y.) in the infusion medium appreciably increases the ultimate yield of pyrogen from the exudate cells (17).…”

“…Preparalion of Pyrogen.--To obtain pyrogen from the granulocytes, the harvested cells were suspended in saline and incubated at 37°C with gentle shaking for 2 hr (17). Unless otherwise stated, each aliquot of 3.5 X 108 cells was suspended in 5 ml of saline.…”

“…Although it has been purified to the point where intravenous injections of 30-40 #g will cause a respectable fever (about 0.7°C) in rabbits (16,17), homogeneity of the final product has not been achieved (14)(15)(16)(17).…”

“…(Received for publication 9 October 1967) The endogenous pyrogen that is produced by rabbit granulocytes (1)(2)(3)(4)(5) and acts as a messenger molecule in experimental fevers (2, 6--13), is known to contain an essential protein moiety and to have a molecular weight of 10--20,000 (14)(15)(16)(17). Although it has been purified to the point where intravenous injections of 30-40 #g will cause a respectable fever (about 0.7°C) in rabbits (16,17), homogeneity of the final product has not been achieved (14)(15)(16)(17).…”