Arginine-specific gingipain (RgpA) (BR1)

The term Anti-BR1 antibody refers to a novel diagnostic biomarker (autoantibody) found in the serum of patients with rheumatoid arthritis (RA). The target molecule for this antibody is the BR1 peptide, a specific 25-amino acid sequence derived from the arginine-specific gingipain (RgpA) enzyme produced by the periodontal pathogen Porphyromonas gingivalis. This bacterium is strongly linked to the pathogenesis of RA, as its enzymes can induce chronic inflammation and facilitate the citrullination of proteins, leading to the breakdown of self-tolerance. The anti-BR1 antibody test has demonstrated high sensitivity and specificity for RA, particularly in patients who are seronegative for traditional markers like rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA). While the BR1 peptide itself is primarily a diagnostic target, the parent enzyme RgpA is considered a therapeutic target for experimental gingipain inhibitors being developed for conditions such as Alzheimer's disease and periodontitis. In clinical practice, the presence of anti-BR1 antibodies serves as a biomarker to guide the early initiation of disease-modifying anti-rheumatic drugs (DMARDs).

Other names

BR1 peptidePorphyromonas gingivalis RgpA peptide25-mer BR1 peptideGingipain R1RgpA

The BR1 peptide serves as a diagnostic target for autoantibodies in rheumatoid arthritis; it is not a direct target for therapeutic drugs, although the parent enzyme RgpA is a target for experimental gingipain inhibitors.