Interpain A, a Cysteine Proteinase from Prevotella intermedia, Inhibits Complement by Degrading Complement Factor C3
2009

How a Bacterial Protein Helps Prevotella intermedia Avoid Immune Attack

Sample size: 82 publication 10 minutes Evidence: high

Author Information

Author(s): Potempa Michal, Potempa Jan, Kantyka Tomasz, Nguyen Ky-Anh, Wawrzonek Katarzyna, Manandhar Surya P., Popadiak Katarzyna, Riesbeck Kristian, Eick Sigrun, Blom Anna M.

Primary Institution: Lund University, Department of Laboratory Medicine, Section of Medical Protein Chemistry, University Hospital Malmö, Malmö, Sweden

Hypothesis

Does interpain A from Prevotella intermedia inhibit the complement system by degrading complement factor C3?

Conclusion

Interpain A from Prevotella intermedia significantly reduces the bactericidal activity of human serum by degrading complement factor C3.

Supporting Evidence

  • Interpain A was found to be present in 75% of aggressive periodontitis samples and 81% of chronic periodontitis samples.
  • Interpain A significantly inhibited the classical and alternative pathways of the complement system.
  • Addition of a cysteine protease inhibitor enhanced the killing of interpain A-producing strains by human serum.

Takeaway

A protein made by a bacteria called Prevotella intermedia helps it survive by breaking down a part of our immune system that usually kills bacteria.

Methodology

The study used PCR to detect the inpA gene in subgingival plaque samples and assessed the effect of interpain A on the complement system through various assays.

Potential Biases

Potential bias in sample selection and the specificity of PCR assays.

Limitations

The study did not quantify the exact levels of interpain A in gingival crevicular fluid.

Participant Demographics

Patients with chronic and aggressive periodontitis.

Statistical Information

P-Value

p<0.05

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.ppat.1000316

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