IgG purification
IgG was purified from plasma of patients with LN or of healthy donors,
by using Protein G beads (GE Healthcare), as recommended by the
manufacturer. The concentration of the IgG was determined by a Nanodrop
and the purity of IgG – by 10% SDS-PAGE electrophoresis (Invitrogen,
Life technologies, Novex), followed by a Coomassie Blue staining of the
gel.