Human Gastric H,K-Adenosine Triphosphatase β-Subunit Is a Major Autoantigen in Atrophic Corpus Gastritis: Expression of the Recombinant Human Glycoprotein in Insect Cells

Abstract

Ma J-Y, Borch K, Mårdh S. Human gastric H,K-adenosine triphosphatase /5-subunit is a major autoantigen in atrophic corpus gastritis. Expression of the recombinant human glycoprotein in insect cells. Scand J Gastroenterol 1994;29:790-794.

Background: Sera from patients with atrophic corpus gastritis with pernicious anemia frequently contain parietal cell autoantibodies. We have previously demonstrated that the human H,K-adenosine triphosphatase (H,K-ATPase) β-subunit constitutes a major autoantigen. The present study investigates whether the human H.K-ATPase β-subunit is an autoantigen, too. Methods: The gene of the human β-subunit was expressed in insect cells by a baculovirus expression system. The reactivity of sera from 42 patients towards the recombinant glycoprotein was analyzed by means of an enzyme-linked immunosorbent assay. Results: Thirty-nine of the 42 sera (93%) scored positive. Autoantibody binding in 41 sera (98%) was eliminated when unglycosylated β-subunit was used as antigen, and antibody binding in the last serum was decreased by 30%. Conclusions: The results indicate that the β-subunit is indeed a major autoantigen and that carbohydrates are involved in binding of the autoantibodies.

Key Words:

• Autoantibody
• baculovirus
• pernicious anemia