Molecular mimicry among human proteinase 3 and bacterial antigens: implications for development of c-ANCA associated...

Area of Science:

• Immunology
• Microbiology
• Computational Biology

Background:

• Wegener's granulomatosis is an autoimmune disease characterized by autoantibodies targeting human autoantigen PR3.
• The precise origin of these autoantibodies remains unknown, though infections are suspected contributors to autoimmune conditions.

Purpose of the Study:

• To explore potential molecular mimicry between human PR3 and homologous serine proteases from various pathogens using in silico analysis.
• To identify conserved regions and epitopes that could explain cross-reactivity and the development of autoantibodies in Wegener's granulomatosis.

Main Methods:

• In silico analysis was performed to compare human PR3 with thirteen serine proteases from human pathogens.
• Structural homology and amino acid sequence identity were assessed.
• Epitope prediction and multiple sequence alignments were conducted to identify conserved regions and potential cross-reactive sites.

Main Results:

• Thirteen pathogen-derived serine proteases exhibited structural homology and sequence identity with human PR3.
• A single conserved epitope (IVGG) was identified between residues 59-74.
• Conserved regions potentially involved in cross-reactivity were found at specific residue positions (90-98, 101-108, 162-169, 267, and 262).

Conclusions:

• This study provides the first in silico evidence for molecular mimicry between human and pathogen serine proteases.
• This molecular mimicry may elucidate the origins of autoantibodies observed in patients with Wegener's granulomatosis.
• The findings suggest a potential link between microbial infections and the autoimmune response in this disease.