Involvement of lipoprotein PpiA of Streptococcus gordonii in evasion of phagocytosis by macrophages

In this study, we identified a putative lipoprotein, peptidyl‐prolyl cis/trans isomerase (PpiA), and clarified its role in evasion of phagocytosis by macrophages. Attenuation of the gene encoding prolipoprotein diacylglyceryl transferase (Lgt) altered the localization of PpiA from the cell surface to the culture supernatant, indicating that PpiA is lipid‐anchored in the cell membrane by Lgt. Both human and murine macrophages showed higher phagocytic activity towards ppiA and lgt mutants than the wild‐type, indicating that the presence of PpiA suppresses phagocytosis of S. gordonii. Human macrophages treated with dextran sulfate had significantly impaired phagocytosis of S. gordonii, suggesting that class A scavenger receptors in human macrophages are involved in the phagocytosis of S. gordonii. These results provide evidence that S. gordonii lipoprotein PpiA plays an important role in inhibiting phagocytic engulfment and in evasion of the host immune response.
Source: Oral Microbiology and Immunology - Category: Microbiology Authors: Tags: Original Article Source Type: research