Expression levels of cytokines and chemokines increase in human peripheral blood mononuclear cells stimulated by activation of the Toll-like receptor 5 pathway.

ABSTRACT

Recognition of pathogen-associated molecular patterns by Toll-like receptors (TLRs) activates innate and adaptive immune responses. Among the 11 members of the human TLR family, TLR-5 is known to play an important role in the defense against bacterial invasion by binding to flagellin, a conserved component of bacteria. Previous studies have demonstrated that the activation of TLR-5 induces the expression of interleukin (IL)-10, IL-12 and interferon-ß. However, the aim of the present study was to analyze the expression of a wider range of immune-related molecules upon stimulation with a TLR-5 agonist. Following isolation from healthy volunteers, peripheral blood mononuclear cells (PBMCs) were stimulated with flagellin, a TLR-5 agonist. At 4 h after stimulation, quantitative polymerase chain reaction (PCR) and an antibody chip array were conducted to determine the mRNA expression levels of immune molecules and the protein secretion of immune molecules in the supernatant, respectively. The PCR results revealed that activation of TLR-5 significantly influenced the expression of a number of important molecules. In addition, the antibody chip array demonstrated the induction (IL-8) and inhibition [monocyte chemoattractant protein (MCP)-1, MCP-3 and macrophage inflammatory protein-1α) of protein secretion following TLR-5 stimulation. Therefore, the present study demonstrated the importance of TLR-5 in regulating the biological function of PBMCs. In the future, research should focus on the roles of the candidate molecules in TLR-5-mediating functions.