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- Mattsson, E, et al.
(author)
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Superantigens from Staphylococcus aureus induce procoagulant activity and monocyte tissue factor expression in whole blood and mononuclear cells via IL-1 beta
- 2003
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In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 1:12, s. 76-2569
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Journal article (peer-reviewed)abstract
- BACKGROUND: Staphylococcus aureus is one of the most common bacteria in human sepsis, a condition in which the activation of blood coagulation plays a critical pathophysiological role. During severe sepsis and septic shock microthrombi and multiorgan dysfunction are observed as a result of bacterial interference with the host defense and coagulation systems.OBJECTIVES: In the present study, staphylococcal superantigens were tested for their ability to induce procoagulant activity and tissue factor (TF) expression in human whole blood and in peripheral blood mononuclear cells.METHODS AND RESULTS: Determination of clotting time showed that enterotoxin A, B and toxic shock syndrome toxin 1 from S. aureus induce procoagulant activity in whole blood and in mononuclear cells. The procoagulant activity was dependent on the expression of TF in monocytes since antibodies to TF inhibited the effect of the toxins and TF was detected on the surface of monocytes by flow cytometry. In the supernatants from staphylococcal toxin-stimulated mononuclear cells, interleukin (IL)-1 beta was detected by ELISA. Furthermore, the increased procoagulant activity and TF expression in monocytes induced by the staphylococcal toxins were inhibited in the presence of IL-1 receptor antagonist, a natural inhibitor of IL-1 beta.CONCLUSIONS: The present study shows that superantigens from S. aureus activate the extrinsic coagulation pathway by inducing expression of TF in monocytes, and that the expression is mainly triggered by superantigen-induced IL-1 beta release.
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- Sorensen, OE, et al.
(author)
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Processing of seminal plasma hCAP-18 to ALL-38 by gastricsin - A novel mechanism of generating antimicrobial peptides in vagina
- 2003
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In: Journal of Biological Chemistry. - 1083-351X. ; 278:31, s. 28540-28546
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Journal article (peer-reviewed)abstract
- The human cathelicidin, hCAP-18, is expressed both in neutrophils and in epithelial cells. hCAP-18 is processed to the antimicrobial peptide LL-37 by proteinase 3 in neutrophils. hCAP-18 is highly expressed in the epididymis with a subsequent high concentration in seminal plasma where the protein is present in its unprocessed and antimicrobially inactive form. We report here that hCAP-18 in seminal plasma is processed to generate a 38-amino acid antimicrobial peptide ALL-38 by the prostate-derived protease gastricsin when incubated at a pH corresponding to the vaginal pH. In accordance with this, seminal plasma derived hCAP-18 was found in its processed form in the vagina following sexual intercourse. The antimicrobial activity of ALL-38 against a variety of microorganisms tested is equal to that of LL37. This enzymatic activation of a proantimicrobial substance in seminal plasma following exposure to the vaginal milieu represents a novel mechanism to prevent infection following sexual intercourse.
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