[8] The genome of P. gingivalis was described in 2003 revealing 1,990 open reading frames (i.e. protein-coding sequences), encoded by 2,343,479 bp, with an average G+C content of 48.3%.
Rgp degrades large peptides of the host organism to provide the bacterium with an abundant nitrogen and carbon source from human serum albumin.
[12] P. gingivalis can also degrade transferrin within host cells which provides the organism with an abundant iron source needed to perform multiple cellular functions.
[15] Lys- gingipains (Kgp) can bind to immobilized matrix proteins fibrinogen and fibronectin and may have a role in host colonization.
They have the ability to cleave subclass 1 and 3 IgG antibodies[17] as well as proinflammatory cytokines such as IL-1β, IL-2, IL-6, TNF-α and IL-8 in regions of high P. gingivalis concentration,[18] impairing host immune response function.
[19] Gingipains are key factors in tissue damage symptoms of periodontitis, which results from the degradation of matrix metalloproteins, collagen, and fibronectin.
[13] Degradation of these substrates interferes with interactions between host cells and the extracellular matrix, therefore impeding wound healing and causing destruction of periodontal tissues.
[21] Vaccines made from capsular polysaccharide of P. gingivalis apparently impair oral bone loss in murine models.
[22] Fimbriae are appendages involved in cellular attachment and greatly contribute to virulence and are found on many Gram-negative and some Gram-positive bacteria.
[citation needed] P. gingivalis virulence is heavily associated with fimbriae as they have been characterized to be key factors in adhesion, invasion, and colonization.
[23] Fimbriae were also found to be associated with modulating β2 integrin adhesive activity for uptake by monocytes using the CD14/TLR2/PI3K signaling complex, which may contribute to intracellular evasion tactics by P.
[25] They have a role in initial attachment and organization of biofilms, as they act as adhesins that mediate invasion and colonization of host cells contributing to P. gingivalis virulence.
It was found to coadhere and develop biofilm in conjunction with Streptococcus gordonii by interaction with SspB streptococcal surface polypeptide.
It does this by using a combination of gingipain proteases, a capsular polysaccharide, induction of host cell proliferation, and the cleavage of chemokines responsible for neutrophil recruitment.
In a study using a mouse model, P. gingivalis was specifically found to down-regulate IL-8 induction, causing delayed neutrophil recruitment.
[17] Other studies have found that P. gingivalis can subvert the complement pathway through C5αR and C3αR, which modulates the killing capacity of leukocytes, allowing for uncontrolled bacterial growth.
[26] Interproximal and horizontal alveolar bone loss in mouse models are seen in coinfections involving P. gingivalis and Treponema denticola.
[29] While P. gingivalis is a part of the typical microbiotic ecosystem of the oral cavity in humans, it can also become pathogenic is provided with sufficient opportunity.
The inflammation pathway of periodontitis is such that as the infection grows, bacteria, including P. gingivalis are targeted by neutrophils and natural killer immune cells.
P. gingivalis has been shown to accelerate the atherosclerosis disease pathway in mice, as well as being found in human atherosclerotic plaque lesions.