title: Helicobacter pylori infection affects immune responses following vaccination of typhoid-naive U.S. adults with attenuated Salmonella typhi oral vaccine CVD 908-htrA.
abstract: BACKGROUND
  We examined the association between Helicobacter pylori infection and the immune response following oral immunization of US adults with attenuated Salmonella Typhi vaccine CVD 908-htrA.
  
  
  METHODS
  Baseline sera from 74 volunteers without a history of typhoid fever who were immunized orally with CVD 908-htrA were tested by enzyme-linked immunosorbent assay for immunoglobin G (IgG) antibodies to H. pylori, hepatitis A antibodies (a marker of low socioeconomic status and exposure to enteric infections), and pepsinogen (PG) I and II levels (measures of gastric inflammation). IgG against S. Typhi lipopolysaccharide (LPS) O and flagella was measured before and 28 days following immunization; a ≥4-fold increase in titer from baseline constituted seroconversion.
  
  
  RESULTS
  Seroconversion of S. Typhi IgG LPS antibodies was significantly higher among vaccinees infected with H. pylori versus uninfected subjects: adjusted odds ratio (OR) 3.8, 95% confidence interval (CI), 1.1-12.6 (P = .03). A low PG I:PG II ratio (<5), indicating more advanced corpus gastritis, increased the odds of seroconversion of IgG S. Typhi flagella antibody (adjusted OR 6.4, 95% CI, 1.3-31.4; P = .02). Hepatitis A infection did not influence the immune response to CVD 908-htrA.
  
  
  CONCLUSIONS
  H. pylori infection and gastric inflammation may enhance humoral immunity to oral attenuated S. Typhi vaccine.
authors.affiliation: Center for Vaccine Development.
authors.forename: Khitam
authors.initials: K
authors.lastname: Muhsen
authors.forename: Marcela F
authors.initials: MF
authors.lastname: Pasetti
authors.forename: Mardi K
authors.initials: MK
authors.lastname: Reymann
authors.forename: David Y
authors.initials: DY
authors.lastname: Graham
authors.forename: Myron M
authors.initials: MM
authors.lastname: Levine
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D018592:Cross-Over Studies; D004306:Dose-Response Relationship, Immunologic; D004311:Double-Blind Method; D005260:Female; D016481:Helicobacter Infections / Q000097:blood / Q000276:immunology*; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D056724:Immunity, Humoral / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D015999:Multivariate Analysis; D010919:Placebos; D022562:Salmonella Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology*; D012485:Salmonella typhi / Q000276:immunology*; D014481:United States; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G; D010919:Placebos; D022562:Salmonella Vaccines; D014613:Vaccines, Attenuated
keywords: Helicobacter pylori; Salmonella Typhi; humoral immunity; immunogenicity; oral vaccines; serum pepsinogens