title: Avidity maturation of antibody to Haemophilus influenzae type b (Hib) after immunization with diphtheria-tetanus-acellular pertussis-hib-hepatitis B combined vaccine in infants.
abstract: Antibody avidity to Haemophilus influenzae type b (Hib) polysaccharide (PS) was assessed in infants vaccinated with diphtheria-tetanus-acellular pertussis (DTaP) combined with Hib-PS conjugated to tetanus toxoid (PRP-T) and hepatitis B (HB) (DTaP-PRP-T-HB) and after a PRP-conjugate (CRM197-OS) booster 3-7 months later. Avidity differed between infants with anti-Hib-PS IgG antibody <1 or >1 microg/mL postprimary series (avidity index [AI], 42%, 95% confidence interval [CI], 35%-49%, and 68% and 63%-72%, respectively; P<.0001). For infants with <1 microgram/mL anti-Hib-PS IgG antibody, mean AI rose by the time of preboost immunization to 61% (95% CI, 57%-65%), even though total IgG antibody levels fell. Spontaneous Hib-PS antibody rises after primary series DTaP-PRP-T-HB vaccination were followed by high postboost anti-Hib-PS IgG antibody levels and avidity. The DTaP-PRP-T-HB combination vaccine studied elicits high avidity antibody, and affinity maturation appears to occur in the absence of further antigen exposure even in those with very low anti-Hib-PS antibody.
authors.affiliation: University of Rochester Medical Center, Elmwood Pediatric Group, Rochester, NY 14642, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Pichichero
authors.forename: T
authors.initials: T
authors.lastname: Voloshen
authors.forename: D
authors.initials: D
authors.lastname: Zajac
authors.forename: S
authors.initials: S
authors.lastname: Passador
mesh_terms: D000915:Antibody Affinity; D000917:Antibody Formation; D016001:Confidence Intervals; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000276:immunology*; D018073:Haemophilus Vaccines / Q000276:immunology*; D006193:Haemophilus influenzae / Q000145:classification / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary; D007074:Immunoglobulin G / Q000097:blood*; D007223:Infant; D018074:Vaccines, Conjugate / Q000276:immunology*
chemical_list: D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; D017325:Hepatitis B Vaccines; D007074:Immunoglobulin G; C103644:Tetracel; D018074:Vaccines, Conjugate; C122182:diphtheria-tetanus-acellular pertussis-Hib-hepatitis B vaccine