Immune evasion strategies of Porphyromonas gingivalis.

Porphyromonas gingivalis is strongly correlated with chronic periodontitis. Its chronic persistence in the periodontium depends on its ability to evade host immunity without inhibiting the overall inflammatory response, which is actually beneficial for this and other periodontal bacteria. Indeed, the inflammatory exudate (gingival crevicular fluid) is a source of essential nutrients, such as peptides and hemin-derived iron. In this review, I discuss how P. gingivalis can promote its adaptive fitness through instigation of subversive crosstalk signaling. These interactions involve Toll-like receptor-2, complement receptor 3, C5a anaphylatoxin receptor, and CXC-chemokine receptor 4. Their exploitation by P. gingivalis allows the pathogen to escape elimination, obtain nutrients, and collaterally inflict periodontal tissue injury.