In contrast, the bactericidal permeability-increasing protein/lipopolysaccharide-binding protein (BPI/LBP) gene, involved in the antimicrobial defense against Gram negative bacteria, showed a significant up-regulation at 2 and 6 h post-infection only in cells inoculated with the live bacteria compared with the control and formalin-killed inoculated treatments (Figure 2F). Here, LBP is linked to infection.