Studies on the pathogenesis of fever. X. The effect of certain enzyme inhibitors on the production and activity of leucocvtic pvrogen.
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The production of endogenous pyrogen by intact granulocytes obtained from acute peritoneal exudates is blocked by arsenite, iodoacetate, p-chloromercuribenzoate, and N-ethylmaleimide in concentrations of 2 x 10(-4)M. When the concentration of these sulfhydryl-reactive enzyme inhibitors is increased to 2 x 10(-2)M, only the iodoacetate inactivates the pyrogen molecule, whereas the arsenite, the p-chloromercuribenzoate, and the N-ethylmaleimide have no gross effect upon its thermogenic activity. Both diisopropyl fluorophosphate and dinitrofluorobenzene are even more potent inactivators of the pyrogen molecule than iodoacetate, although the action of the DFP cannot be blocked or reversed by known antagonists such as 2-pyridine aldoxime methiodide and hydroxylamine. Proteolytic enzymes, potentially capable of degrading leucocytic pyrogen, are released from polymorphonuclear leucocytes, along with the pyrogen, when the cells are incubated in normal salt solution. These enzymes are readily activated by a sufficient concentration of glutathione (2 x 10(-2)M). They are not present in preparations of partially purified leucocytic pyrogen from which much of the non-pyrogenic protein has been removed. Glutathione by itself, even at concentrations as high as 2 x 10(-1)M, does not affect in the gross the thermogenic activity of the purified pyrogen. The implications of these findings in relation to both the production and the chemical characteristics of leucocytic pyrogen are discussed. (+info)
Studies on the pathogensis of fever. IX. The production of endogenous pyrogen by polymorphonuclear leucocytes.
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Determination of the dose-response curve for rabbit leucocytic pyrogen reveals a hyperthermic "ceiling" at which there is a marked insensitivity to dosage. This finding has important implications in relation to the quantitative assay of leucocytic pyrogen. Polymorphonuclear leucocytes separated from normal rabbit blood possess the capacity to produce less than 5 per cent of the pyrogen generated by the same number of rabbit granulocytes collected from acute peritoneal exudates. Blood granulocytes, separated in the cold from the buffy coat, contain no detectable preformed pyrogen. The amount of preformed pyrogen within exudate granulocytes represents but a small fraction of the pyrogen which the cells are capable of generating when incubated in normal saline at 37 degrees C. It is suggested that the active pyrogen is formed from an inactive precursor within the cells. Under the conditions tested, cell fragments of rabbit granulocytes fail to produce endogenous pyrogen. The fact that the production of pyrogen is blocked at 4 degrees C is in keeping with the hypothesis that it involves metabolic reactions within the cell. (+info)
Pyrogens enhance beta-endorphin release in hypothalamus and trigger fever that can be attenuated by buprenorphine.
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At first, we investigated whether both beta-endorphin release level in the hypothalamus and body temperature can be altered after intracerebroventricular (i.c.v.) injection of either lipopolysaccharide (LPS), interleukin-1beta (IL-1beta), or prostaglandin E(2) (PGE(2)) in rats. It was found that in the rat, i.c.v. administration of either LPS (0.5 microg in 10 microl), IL-1beta (10 ng in 10 microl), or PGE(2) (200 ng in 10 microl), in addition to producing fever, upregulated the immunoreactivity of beta-endorphin in the preoptic anterior hypothalamus of rat brain. Secondarily, we assessed whether the fever induced by either LPS, IL-1beta, or PGE(2) can be altered by pretreatment with buprenorphine (an opioid receptor antagonist). The results revealed that i.c.v. administration of buprenorphine (1 - 10 microg in 10 microl) alone had an insignificant effect on the body temperature. However, the fever induced by i.c.v. injection of either LPS, IL-1beta, or PGE(2) was significantly attenuated by pretreatment with i.c.v. injection of buprenorphine 1 h before the pyrogen injection in rats. The results suggest that pyrogens enhance beta-endorphin release in the hypothalamus and trigger fever which can be attenuated by buprenorphine, an opioid receptor antagonist. (+info)
Platonin, a cyanine photosensitizing dye, inhibits pyrogen release and results in antipyresis.
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Intravenous injection of the supernatant fluids from human peripheral blood mononuclear cells (PBMC) incubated with lipopolysaccharide (LPS) caused fever in rabbits. The fever was in parallel with the levels of either interleukin-1 beta (IL-1 beta), IL-6, or tumor necrosis factor-alpha (TNF-alpha) in supernatant fluids. When incubating the platonin with the LPS-human PBMC, both the levels of IL-1 beta, IL-6, or TNF-alpha in supernatant fluids and the pyrogenicity of supernatant fluids were significantly suppressed. The febrile response to supernatant fluids from the LPS-stimulated PBMC was attenuated almost completely by adding anti-IL-1 beta, but not anti-IL-6 or anti-TNF-alpha, monoclonal antibody to supernatant fluids. In addition, both the fever and the increased levels of either IL-1 beta, IL-6, or TNF-alpha in rabbit serum following an intravenous administration of LPS were significantly attenuated by pretreatment with an intravenous dose of platonin. Furthermore, the fever induced by intravenous injection of IL-1 beta was reduced by pretreatment of rabbits with intravenous injection of platonin. The data indicate that platonin inhibits production of pyrogenic cytokines (in particular, IL-1 beta) from PBMC and results in antipyresis. (+info)
Immune cell lethality induced by streptococcal pyrogenic exotoxin A and endotoxin.
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Streptococcal pyrogenic exotoxin (SPE) A has many effects on the immune system, including immunolethality, which is characterized by a significant decrease in circulating immune cells as well as depletion of the spleen and lymph nodes prior to death of experimental animals. In this report, characterization of the mechanism of immunolethality has been undertaken. Synergistic induction of immunolethality was observed in vitro when human lymphocytes were treated with both SPE A and lipopolysaccharide (LPS). The same effect was demonstrated in the absence of a mitogenic response with the murine T-cell receptor, as well as in the absence of antigen-presenting cells and their secreted cytokines. The addition of antigen-presenting cells did not significantly affect lethality. SPE A directly interacted with LPS through interaction with ketodeoxyoctonate as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and iodinated exotoxin overlays. This interaction was demonstrated to be important for immunolethality, since simultaneous addition of SPE A and LPS was required, whereas sequential addition of SPE A and LPS did not result in lethality. LPS appeared to be acting, in part, to enhance the cell-binding ability of SPE A, since SPE A could only be detected in A.E7 cell membrane preparations after simultaneous incubation with SPE A and LPS. (+info)
Distinct T-cell receptor V beta gene usage by human T lymphocytes stimulated with the streptococcal pyrogenic exotoxins and pep M5 protein.
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A number of streptococcal products, including the streptococcal pyrogenic exotoxin (SPE) types A, B, and C as well as a 22-kDa fragment of M type 5 protein (pep M5), are potent stimulants of human T-lymphocyte blastogenesis and belong to the newly designated family of superantigens. The V beta usage of human T cells stimulated with these toxins was investigated by using the polymerase chain reaction. We demonstrate that SPE A, B, and C as well as pep M5 stimulate the proliferation of T cells in a dose-dependent manner. pep M5 stimulates cells bearing V beta 2, 4, and 8 elements of the T-cell receptor (TCR), whereas SPE A stimulates TCR V beta 2-, 12-, 14-, and 15-bearing cells. SPE B stimulated only cells expressing TCR V beta 8 elements, while SPE C stimulated cells expressing V beta 1, 2, 5.1, and 10. These studies reveal that the preferential usage of particular V beta elements is distinct for these different superantigens, which may be important in the pathogenesis of various streptococcal diseases. (+info)
Interleukin 1 receptor antagonist blocks somnogenic and pyrogenic responses to an interleukin 1 fragment.
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Previously it was shown that human interleukin 1 (huIL-1) and a huIL-1 fragment, huIL-1 beta 208-240, are somnogenic and pyrogenic in rabbits. However, the amino acid sequences for IL-1 are species-specific and it was unknown whether rabbit (rb) IL-1 beta 208-240 and rat (rt) IL-1 beta 208-240 were active in their respective species. Furthermore, it was unknown whether these fragments elicited their effects via the IL-1 receptors. Two doses of rbIL-1 beta 208-240 (6.0 and 12.0 nmol) were intracerebroventricularly administered to rabbits. The 6.0-nmol dose had little effect, whereas the 12.0-nmol dose greatly increased non-rapid-eye-movement sleep across a 6-hr recording period and induced a febrile response. Rats injected intracerebroventricularly with rtIL-1 beta 208-240 at dark onset responded to three doses of the peptide (1.2, 2.4, and 4.8 nmol). The 1.2-nmol dose did not greatly affect sleep but did induce a moderate febrile response. The 2.4- and 4.8-nmol doses increased non-rapid-eye-movement sleep across the 12-hr recording period. Maximal brain temperature elevations relative to controls after the 2.4- and 4.8-nmol doses of the peptide were 0.9 +/- 0.2 degrees C and 0.7 +/- 0.2 degrees C, respectively. These responses in both rabbits and rats were completely blocked or significantly attenuated when the animals were pretreated with an IL-1 receptor antagonist. These results suggest that the biological activities of IL-1 beta 208-240 are mediated via the IL-1 beta receptors. (+info)
Influenza virus pyrogenicity: central role of structural orientation of virion components and involvement of viral lipid and glycoproteins.
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Ultraviolet light-inactivated, non-infectious influenza virus is pyrogenic; virion components are probably responsible for this pyrogenicity. To try to identify the pyrogenic component, influenza virions were disrupted with either bromelain or sodium deoxycholate (DOC). Treatment of infectious virions with bromelain, under conditions that removed the surface glycoproteins (spikes), destroyed their pyrogenicity. The supernatant, containing non-aggregated and modified glycoproteins, was also non-pyrogenic. Disruption of virions with DOC considerably reduced pyrogenicity; however, some was retained by the sub-viral cores. Viral nucleoprotein and matrix protein, purified from the supernatant, were non-pyrogenic. Aggregated stellate clusters of surface glycoproteins separated on sucrose gradients were pyrogenic in half of numerous tests performed with different batches of material. Treatment of virus with ether resulted in complete loss of pyrogenicity. Liposomes made from extracted viral lipid were non-pyrogenic. In contrast, virosomes made from the viral lipid and the aggregated stellate clusters of surface glycoproteins were pyrogenic. Hence, optimum pyrogenicity depends upon the integrity of the virus particle, but haemagglutinin and/or neuraminidase appear essential, and lipid may be involved. (+info)