Serum IgG response to differentiated antigens of Helicobacter pylori

AIM To detect antibodies against Helicobacter pylori spiral and coccoid antigens in human sera. METHODS Blood samples were collected from 278 patients with gastric diseases. A 3-day-old culture of H, pylori on chocolate blood agar was used to provide spiral form. 'Synchronous' coccoids were cultured in (BHY) (brain heart infusion supplemented with 10% horse serum and 0.4% yeast extract) medium in a chemostat, Antigens from spiral and coccoid form were prepared using acid glycine extraction. Enzyme-linked immunosorbent assay (ELISA) was performed to detect serum IgG antibodies against spiral and coccoid forms of H, pylori. RESULTS Seroprevalence of H. pylori infection was higher in patients with gastric ulcer (79%) and gastric cancer (83%) than those with non-ulcer dyspepsia (NUD) (44%) and other diseases (45%) (P<0.05). IgG antibodies against spiral and coccoid antigens were detected in 50.7% (141/278) and 49.6% (138/278), respectively. CONCLUSION The spiral and coccoid forms of H. pylori coexist in patients infected with the bacterium.