Detection of human antibodies binding with smooth and rough LPSs from Proteus mirabilis O3 strains S1959, R110, R45

Area of Science:

• Immunology
• Microbiology
• Rheumatology

Background:

• Proteus bacteria are facultative pathogens linked to urinary tract infections, bacteremia, and rheumatoid arthritis (RA).
• Lipopolysaccharide (LPS) from Proteus species contains epitopes that may cross-react with host antigens.
• Molecular mimicry is a proposed mechanism in the pathogenesis of RA.

Purpose of the Study:

• To compare antibody titers against Proteus mirabilis lipopolysaccharide (LPS) in healthy individuals and RA patients.
• To investigate the presence of antibodies recognizing specific lysine-galacturonic acid epitopes in Proteus LPS.
• To explore the potential role of anti-LPS antibodies in molecular mimicry in RA.

Main Methods:

• Enzyme-linked immunosorbent assay (ELISA) was used to quantify antibody titers.
• LPS from wild-type and mutant strains of Proteus mirabilis (O3) were utilized.
• Antibodies were analyzed in plasmas from healthy blood donors and sera from RA patients.

Main Results:

• Antibody titers against Proteus mirabilis LPS increased with age in blood donors.
• Both healthy individuals and RA patients possessed antibodies against different forms of Proteus O3 LPS (smooth, Ra, and Re types).
• Antibodies targeting lysine-galacturonic acid epitopes were detected in both groups, with potential implications for RA.

Conclusions:

• Antibodies against Proteus mirabilis LPS are present in both healthy and RA populations.
• The detection of these antibodies suggests a potential role for molecular mimicry involving Proteus LPS in the pathogenesis of RA.
• Further research is warranted to elucidate the precise mechanisms of anti-LPS antibodies in RA development.