Skip to main content
Fig. 2 | Arthritis Research & Therapy

Fig. 2

From: Anti-peptidylarginine deiminase-4 antibodies at mucosal sites can activate peptidylarginine deiminase-4 enzyme activity in rheumatoid arthritis

Fig. 2

Analysis of anti-PAD4 antibody isotypes and ability to activate PAD4. a, b IgG- (blue), IgA- (red), and IgM-specific (green) immunoprecipitations were performed on paired serum (Se), sputum (Sp), and saliva (Sa) of individuals with anti-PAD4 antibodies (n = 7) to define the isotypes of anti-PAD4 a and the anti-PAD3/4 subset b at each anatomic site. The total reactivity to PAD4 or PAD3/4 was calculated, and the % reactivity of each antibody isotype is shown. c, d No IgG or purified total IgG and IgA from serum c or sputum d from anti-PAD-negative (P0), anti-PAD4 mono-reactive (P4), or anti-PAD3/4 cross-reactive (XR) RA or at-risk (AR*) samples was pre-incubated with PAD4, prior to incubation with histone H3 substrate and either 0.2 or 2.0mM calcium at 37°C. Immunoblotting was performed to detect citrullination of histone H3 (cit-H3), human IgG (heavy chain; IgG-Hc), and human IgA (heavy chain; IgA-Hc). Monomeric IgA (open arrowheads) and multimeric IgA (closed arrowheads) are indicated

Back to article page