Fig. 3.
Proliferation of human mesangial cells stimulated with immune complexes formed in vitro using cord-blood serum supplemented with Gal-deficient IgA1 myeloma protein. Gal-deficient IgA1 (Mce) myeloma protein (80 μg, filled circles, corresponding to final concentration of 10 μg/ml culture medium) was added to 160 μl cord-blood serum. After overnight incubation at 4 °C to allow formation of immune complexes, the samples were fractionated on a calibrated Superose 6 column, and the resultant fractions were filter-sterilized and added to serum-starved human mesangial cells. Cellular proliferation was measured after overnight incubation. Panel (a) shows relative cellular proliferation (empty circles represent activity of cord-blood serum without any supplementation), panel (b) shows IgA concentration, and panel (c) shows the amount of IgG–IgA immune complexes in the collected fractions. V0, void volume.