Detection of hmAchR M3 autoantibodies in sera of PBC patients by Western Blot analysis. Detection of autoantibodies to the recombinant human muscarinic acetylcholine receptor M3 (M3R) in the sera from PBC patients was revealed by Western blot analysis. M3R was derived from the membrane fraction of M3R over-expressing Sf9 cells (0.5 μg/lane). PDC (1 μg/lane) was used as control for the PBC sera. Sera were diluted 1:200 and visualized by the anti-human IgG secondary antibody. Given are exemplary the blots of two sera with positive (PBC-1 and 2) and two sera with negative results (PBC-3 and 4) to the M3R, as well as one negative control.