INNATE IMMUNITY, cilt.19, sa.6, ss.631-643, 2013 (SCI-Expanded)
The objective of the present study was to investigate the lipopolysaccharide (LPS) and lipotechoic acid (LTA)-induced TLRs, associated signaling molecules and inflammatory mediators, as well as to compare their combined effect in porcine alveolar macrophages. Macrophages were incubated for 24 h with various concentrations of LPS, LTA, LPS plus LTA or control. Multiple concentrations of LPS elicited the marked up-regulation in mRNA for TLR-2 and-4, CD-14, MD-2, MyD-88, IRAK-4, TRAF-6, as compared to control. LTA had no effect on TLR-4 and MD-2; only higher doses up-regulated TLR-2, CD-14, MyD-88, IRAK-4 and TRAF-6 mRNA. LPS-activated cells released IL1-ß, IL12-ß, TNF-?, IL-6, IL-8, IFN-? and IL-10 in a dose-dependent manner while LTA had no effect on IL-1ß, IL-6 and IFN-?. Higher doses of LTA induced IL-12ß, TNF-?, IL-8 and IL-10. Combined stimulation augmented TLR-2, CD-14 and MyD-88 mRNA, and subsequently produced elevated levels of IL-6, TNF-? and IL-8 when compared to LPS and LTA alone. Additionally, phagocytosis of macrophages was significantly increased following low concentration of LPS treatment. Only low levels of nitric oxide were detected in LPS group. Overall, compared to LPS, LTA was a relatively weak inducer, and co-stimulation accelerated genes and cytokines production associated with pulmonary innate immune function.