Leptospira interrogans activation of peripheral blood monocyte glycolipoprotein demonstrated in whole blood by the release of IL-6

Abstract

Glycolipoprotein (GLP) from pathogenic serovars of Leptospira has been implicated in the pathogenesis of leptospirosis by its presence in tissues of experimental animals with leptospirosis, the inhibition of the Na,K-ATPase pump activity, and induced production of cytokines. The aims of the present study were to investigate the induction of IL-6 by GLP in peripheral blood mononuclear cells (PBMC) and to demonstrate monocyte stimulation at the cellular level in whole blood from healthy volunteers. PBMC were stimulated with increasing concentrations (5 to 2500 ng/ml) of GLP extracted from the pathogenic L. interrogans serovar Copenhageni, lipopolysaccharide (positive control) or medium (negative control), and supernatants were collected after 6, 20/24, and 48 h, and kept at -80ºC until use. Whole blood was diluted 1:1 in RPMI medium and cultivated for 6 h, with medium, GLP and lipopolysaccharide as described above. Monensin was added after the first hour of culture. Supernatant cytokine levels from PBMC were measured by ELISA and intracellular IL-6 was detected in monocytes in whole blood cultures by flow-cytometry. Monocytes were identified in whole blood on the basis of forward versus side scatter parameters and positive reactions with CD45 and CD14 antibodies. GLP (≥50 ng/ml)-induced IL-6 levels in supernatants were detected after 6-h incubation, reaching a peak after 20/24 h. The percentage of monocytes staining for IL-6 increased with increasing GLP concentration. Thus, our findings show a GLPinduced cellular activation by demonstrating the ability of GLP to induce IL-6 and the occurrence of monocyte activation in whole blood at the cellular level.

Pulmonary Disease in Hamsters Infected with Leptospira interrogans: Histopathologic Findings and Cytokine mRNA Expressions

“…It was later demonstrated that the GLP induced cytokine production in peripheral blood monocytes from healthy volunteers. 4,5 The presence of inflammatory cytokines has also been confirmed in sera of patients with leptospirosis. 6 Marinho and others 7,8 showed that high levels of tumor necrosis factor (TNF)-a and interleukin (IL)-6 in the supernatant of peritoneal macrophage cellular culture of genetically selected mice inoculated with a sample of Leptospira interrogans serovars Canicola was determined by immunoenzymatic assays.…”

High levels of serum mannose-binding lectin are associated with the severity of clinical signs of leptospirosis

“…Thus, the elevated MBL levels found in the patients from 2001 could be related to the inflammatory response and the presence of Leptospira virulence factors such as glycoprotein of pathogenic Leptospira (17). The lower levels of MBL found in the 2002 group suggest that the inflammatory response to infection was milder due to an effective immune response or the lack of Leptospira virulence factors in most cases.…”

“…Dorigatti et al (17), using glycoprotein of pathogenic L. interrogans serovar Copenhagen from a patient with Weil's syndrome, demonstrated the induction of IL-6 production and activation of monocytes by this component. Thus, the elevated MBL levels found in the patients from 2001 could be related to the inflammatory response and the presence of Leptospira virulence factors such as glycoprotein of pathogenic Leptospira (17).…”

“…The variability of Leptospira glycoproteins and antigens associated with lipopolysaccharide may be implicated in the differential binding ability of MBL, and, thus, its inflammatory modulation potential by complement activation and monocyte cytokine production (10,(17)(18)(19).…”

Cytokine profile of patient’s sera of Leptospirosis to OMP of Leptospira interrogans serovar tarassovi

“…Studies by Dorigatti et al 4 has shown that OMP of pathogenic Leptospira when inoculated to tubular cells in culture activated nuclear NF Kappa B binding and stimulated downstream inducible nitric oxide (INOS), monocyte chemoattractant protein-1 (MOP-1) and tumor necrosis factor. Another study reported by Magrinho et al 5 detected TNFα and IL-6 in rat renal experimentally infected with L.canicola.…”