Western blot analysis of Human IgA was performed by loading 25 µg of Raji (lane 1), Ramos (lane 2) and mouse spleen (lane 3) cell lysates onto an SDS polyacrylamide gel. Proteins were transferred to a PVDF membrane and blocked at 4ºC overnight. The membrane was probed with a Rabbit anti-Human IgA (alpha-Heavy Chain) secondary antibody (Product # PA5-16388) at a dilution of 1:200 overnight at 4°C, washed in TBST, and probed with an HRP-conjugated secondary antibody for 1 hr at room temperature in the dark. Chemiluminescent detection was performed using Pierce ECL Plus Western Blotting Substrate (Product # 32132). Results show a band at ~50-75 kDa.