Tlr2, Tlr4, Cd14, Cd11b, and Cd11c Expressions on Monocytes Surface and Cytokine Production in Patients With Sepsis, Severe Sepsis, and Septic Shock

Abstract

Bacterial recognition and induced cellular activation are fundamental for the host control of infection, yet the limit between protective and harmful response is still inexact. Forty-one patients were enrolled in this study: 14 with sepsis, 12 with severe sepsis, and 15 with septic shock. Seventeen healthy volunteers (HV) were included as control. The expression of TLR2, TLR4, CD14, CD11b, and CD11c was analyzed on monocytes surface in whole blood. sCD14 was measured in serum, and TNF-alpha, IL-6, and IL-10 cytokine levels were measured in PBMC supernatants after LPS, IL-1beta, and TNF-alpha stimuli by ELISA. An increase in sCD14 and a decreased mCD14 were found in patients as compared with HV (P < 0.001). However, no differences in the expression of TLR2, TLR4, and CD11c were found among the groups. A trend toward differential expression of CD11b was observed, with higher values found in patients with sepsis as compared with HV. A negative regulation of the inflammatory cytokine production was observed in patients with severe sepsis and shock septic in relation to sepsis and HV, regardless of the stimulus. No significant difference in IL-10 production was found among the groups. In this study, we show that the inflammatory response is associated with the continuum of clinical manifestations of sepsis, with a strong inflammatory response in the early phase (sepsis) and a refractory picture in the late phases (severe sepsis and septic shock). Correlation between cell surface receptors and cytokine production after IL-1beta and TNF-alpha stimuli and the observation of a single and same standard response with the different stimulus suggest a pattern of immunology response that is not dependent only on the expression of the evaluated receptors and that is likely to have a regulation in the intracellular signaling pathways.

Bacterial Superantigens Enhance the In Vitro Proinflammatory Response and In Vivo Lethality of the TLR2 Agonist Bacterial Lipoprotein

“…Superantigens have been shown to upregulate the expression of both TLR2 and TLR4 on isolated human monocytes (6,7,26), which was also observed in the current study (data not shown). Although this upregulation by superantigen of TLRs may play a role in the increased responsiveness of the innate immune system in superantigen-mediated septic shock, other research has shown that in patients with severe sepsis, TLR expression does not correlate well with ligand sensitivity (31,32). We therefore analyzed the effect of superantigens on other aspects of the TLR-mediated intracellular signal transduction pathway.…”

Receptors involved in cell activation by antiphospholipid antibodies

“…Increased expression of TLR2 by EC in response to inflammatory mediators such as TNF, LPS, IL-1β, IFNγ and histamine in vivo and in vitro [49][50][51][52], however, provides a mechanism allowing EC to respond to TLR2 ligands under inflammatory conditions. TLR2 and TLR4 are both expressed on platelets [53] and on monocytes [54]. Sorice et al [55] have identified that TLR4, β2GP1 and annexin A2 form an activation cluster in plasma membrane microdomains of human monocytes after LPS or aPLA ligation.…”

IL-1R–Associated Kinase-1 Mediates Protein Kinase Cδ-Induced IL-1β Production in Monocytes

“…THP1 cells (1 3 10 6 ) after different treatments were harvested and washed twice with PBS. For detection of surface markers, cells were resuspended in Ca 2+ -Mg 2+ HBSS and incubated with conjugated primary Abs (TLR2-rPE, TLR4-FITC, CD11b-rPE, and CD36-FITC) for 30 min in the dark at 37˚C as described earlier (26,27). After labeling, cells were washed with PBS and resuspended in 1 ml Ca 2+ -Mg 2+ HBSS, and 10,000 events were analyzed by FACS.…”