SDS-PAGE: 4-12% Bis-Tris NuPAGE gel Lane 1: 5 µg IgA (reduced/heated) Lane 2: 10 µg IgA (reduced/heated) Lane 3: 20 µg IgA (reduced/heated) Lane 4: Molecular weight markers Lane 5: 5 µg IgA (non-reduced/no heat) Lane 6: 10 µg IgA (non-reduced/no heat) Lane 7: 20 µg IgA (non-reduced/no heat)