RT-qPCR analysis of the expression of key components of the host innate immune response to infection, such as the chemokines/cytokines CCL20, CXCL8, TNF-α, the two β-defensins, LAP and TAP and the acute phase protein SAA3 [37–44], confirmed the different abilities of R- and S-LPS to stimulate PS cells (Fig 7A). This evidence concerns the gene TNF and infection.