Effect of Exposure of Raw264.7 Macrophages to Salmonella typhimuriumComponents on Cell Viability, Cytoskeleton Re-arrangement and Cytokine Secretion

Abstract

Innate immune system plays an important role in individual\u27s protection against pathogens and in activation of adaptive immune system. Utilizing RAW 264.7 murine macrophages as an innate immune response representative in this study, we analyzed the effect of invasive pathogen\u27s components (e.g. flagellin) on the arrangement of macrophage\u27s cytoskeleton, on viability of immune cells and on secretion of pro-inflammatory and anti-inflammatory cytokines and on fluorescence intensity of cytoskeleton after rearrangement. Additionally, we studied the similarity and differences between bacterial (Salmonella typhimurium) and synthetic TLR4 agonist (synthetic lipid-A) on viability, fluorescence intensity, cytokine secretion, and cytoskeleton rearrangements. Similarly, we studied the differences between TLR2 receptor agonist from gram-negative and the TLR2/6 receptor agonist from gram-positive bacteria. Flagellin at highest concentration (10 [micro]g/ml) decreased the macrophages viability significantly and increased the tubulin fluorescence intensity significantly. S. typhimurium\u27s LPS and highest concentration of synthetic lipid A (10 [micro]g/ml) decreased the cell viability dramatically. However, the intensity of microtubules was dramatically lower in the S. typhimurium\u27s LPS compared to synthetic lipid A at 5 and 10 [micro]g/ml concentrations. Both bacterial and synthetic TLR4 agonists elevate fluorescence intensity of microfilaments significantly. TLR2/6 agonists from grampositive bacteria decrease the cell viability more than TLR2 agonist from gram negative but not significantly; however, the fluorescence intensity of microtubules was significantly increased in TLR2 agonist in compared to TLR2/6 agonists at all concentrations. S. typhimurium at a concentration (106 cell/ml) that activates TLR4 induced production of IL-6, IL-10, and TNF-[alpha] significantly. Additionally, di-acylated lipoprotein at 5[micro]l induced very high levels of IL-10 secretion compared to control

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