DETECTION OF SERUM ANTIBODIES TO CAGA AND VACA AND OF SERUM NEUTRALIZING ACTIVITY FOR VACUOLATING CYTOTOXIN INPATIENTS WITH HELICOBACTER PYLORI-INDUCED GASTRITIS

Thirty patients with dyspepsia, with histological diagnosis of gastrit is, and with endoscopic diagnosis of peptic ulcer disease (PUD) (n = 1 3) or nonulcer dyspepsia (NUD) (n = 17) Here admitted to the study, He licobacter pylori vacuolating cytotoxin-producing strains (Tox(+)) wer e isolated from 14 (46.7%) patients, whereas non-cytotoxin-producing ( Tox(-)) H. pylori strains were isolated from the remaining patients, O f 30 patients studied, 20 (66.7%) had serum cytotoxin neutralizing act ivity in vitro. Fourteen patients with Tox(+) H. pylori strains showed serum cytotoxin neutralizing activity and serum immunoglobulin G (IgG ) and IgA antibodies reactive with both 87-kDa H. pylori vacuolating c ytotoxin (VacA) and 128-kDa cytotoxin associated gene product (CagA) b y immunoblotting using native enriched preparations of VacA and CagA p roteins from H. pylori culture supernatants as the antigens, A 94-kDa antigen cross-reacting with the 87-kDa VacA protein could be demonstra ted in culture supernatant with immune sera from humans and animals. A il patients (n = 10) lacking serum neutralizing activity were also neg ative for IgG or IgA against VacA antigen, whereas 6 of the 10 patient s showed Iga; serum antibody responses against CagA antigen, The preva lence of antibodies to VacA and CagA antigens was significantly (P < 0 .001) higher in patients with gastritis (20 and 26 patients for VacA a nd CagA, respectively, of 30 patients) than in H. pylori culture-negat ive controls (0 of 27 for both VacA and CagA) and in randomly selected blood donors (17 and 21 for VacA and CagA, respectively, of 120 subje cts), All patients with PUD had antibodies to CagA, whereas 13 of 17 ( 76.5%) patients with NUD had anti-CagA antibodies. Serum IgG antibodie s to VacA were present in 9 (69.2%) patients with PUD of 13 patients a nd in 11 (64.7%) patients with NUD of 17 patients, Anti-CagA antibodie s seemed to correlate better with PUD than anti-VacA antibodies.