title: Elevated levels of maternal anti-tetanus toxin antibodies do not suppress the immune response to a Haemophilus influenzae type b polyribosylphosphate-tetanus toxoid conjugate vaccine.
abstract: Reported are the effects of elevated levels of anti-tetanus antibodies on the safety and immune response to a Haemophilus influenzae type b polyribosylphosphate (PRP)-tetanus toxoid conjugate (PRP-T) vaccine. A group of Thai infants (n = 177) born to women immunized against tetanus during pregnancy were vaccinated with either a combined diphtheria-tetanus-pertussis (DTP) PRP-T vaccine or DTP and a PRP-conjugate vaccine using Neisseria meningitidis group B outer-membrane proteins as a carrier (PedVax HIB). Although most infants possessed high titres (> 1 IU/ml) of anti-tetanus antibodies, the DTP-PRP-T combined vaccine engendered an excellent antibody response to all vaccine components. In both vaccine groups > 98% of infants attained anti-PRP antibody titres > or = 0.15 microgram/ml. The geometric mean anti-PRP antibody titres were 5.41 micrograms/ml and 2.1 micrograms/ml for infants immunized with three doses of PRP-T versus two doses of PedVax HIB vaccines, respectively (P < 0.005). Similarly, the proportion of infants who achieved titres > or = 1 microgram/ml was higher in the PRP-T group (87.8%) than in the group immunized with PedVax HIB (74.2%) (P = 0.036). A subgroup analysis showed that there was no significant difference in the anti-PRP antibody response for infants exhibiting either < 1 IU of anti-tetanus antibody per millilitre or > or = 1 IU/ml at baseline. These finding indicate that pre-existing anti-carrier antibody does not diminish the immune response to the PRP moiety. All infants possessed protective levels of anti-D and anti-T antibody levels after immunization.
authors.affiliation: Udornthani Hospital, Thailand.
authors.forename: C
authors.initials: C
authors.lastname: Panpitpat
authors.forename: U
authors.initials: U
authors.lastname: Thisyakorn
authors.forename: T
authors.initials: T
authors.lastname: Chotpitayasunondh
authors.forename: E
authors.initials: E
authors.lastname: Fürer
authors.forename: J U
authors.initials: JU
authors.lastname: Que
authors.forename: T
authors.initials: T
authors.lastname: Hasler
authors.forename: S J
authors.initials: SJ
authors.lastname: Cryz
mesh_terms: D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000097:blood*; D016667:Bacterial Capsules; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000276:immunology*; D005260:Female; D018073:Haemophilus Vaccines / Q000276:immunology*; D006801:Humans; D007112:Immunity, Maternally-Acquired; D007223:Infant; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D011247:Pregnancy; D013744:Tetanus Toxin / Q000276:immunology*; D018074:Vaccines, Conjugate / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; C044237:Haemophilus influenzae type b polysaccharide vaccine; D011135:Polysaccharides, Bacterial; D013744:Tetanus Toxin; D018074:Vaccines, Conjugate