Evidence for induction of polysaccharide specific B-cell-memory in the 1st year of life: plain Haemophilus influenzae type b-PRP (Hib) boosters children primed with a tetanus-conjugate Hib-DTPa-HBV combined vaccine.

Abstract

UNLABELLED:

The lack of an adequate immune response to the major polysaccharide of the Haemophilus influenzae type b (Hib) capsule (polyribosyl ribitol phosphate) (PRP) in very young infants (< 18 months) can be overcome by conjugating PRP to a T-cell dependent carrier protein. We studied whether administration of a tetanus-PRP conjugate vaccine reconstituted with a diphtheria-tetanus-acellular pertussis-hepatitis B (DTPa-HBV) vaccine as a three dose primary course at 3, 4 and 5 months of age induced PRP-specific immunological memory, by examining the anti-PRP response to a dose of unconjugated PRP given with the DTPa-HBV booster approximately 1 year later. The unconjugated PRP elicited protective anti-PRP antibody levels (> or = 0.15 microgram/ml) in all but 3 of the 369 vaccinees, including 13 infants who failed to demonstrate a measurable immune response after the primary course. In a sub-cohort of 54 subjects all had anti-PRP levels > or = 0.5 microgram/ml within 7-14 days of the booster showing a rapid anamnestic type response. Both primary and booster responses were predominantly IgGl indicating a T-cell dependent response. The DTPa-HBV components elicited protective anti-diphtheria, anti-tetanus and anti-HBs antibody levels in > or = 98.5% of vaccinees, and immune responses to each of the acellular pertussis vaccine components in 92.3%-97.3% of subjects.

CONCLUSION:

The tetanus-PRP conjugate vaccine not only elicited a good primary humoral response, but also induced immunological memory so that the infants were able to mount a large and rapid immune response to subsequent exposure to plain PRP, indicating that protection against circulating wild-type Hib had been generated. Successful induction of immunological memory occurred even when there was no measurable humoral anti-PRP response to the primary course. Tetanus-PRP conjugate vaccine can be used in combination with DTPa-HBV vaccine, when administered separately or as a single injection in the same syringe, in primary immunisation schedules at 3, 4 and 5 months of age.

• Authors: F Zepp, H J Schmitt, A Kaufhold, A Schuind, M Knuf, P Habermehl, C Meyer, H Bogaerts, M Slaoui, R Clemens
• Journal: European journal of pediatrics (Eur J Pediatr) Vol. 156 Issue 1 Pg. 18-24 (Jan 1997) ISSN: 0340-6199 [Print] Germany
• PMID: 9007484 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial)

Chemical References

• Diphtheria-Tetanus-Pertussis Vaccine
• Haemophilus Vaccines
• Hepatitis B Vaccines
• Tetanus Toxoid
• Vaccines, Combined
• Vaccines, Conjugate

Topics

• Age Factors
• Analysis of Variance
• Antibody Formation (immunology)
• Cross Reactions
• Diphtheria-Tetanus-Pertussis Vaccine
• Female
• Haemophilus Infections (prevention & control)
• Haemophilus Vaccines
• Hepatitis B Vaccines
• Humans
• Immunization Schedule
• Immunization, Secondary
• Immunologic Memory
• Infant
• Male
• Tetanus Toxoid
• Vaccines, Combined
• Vaccines, Conjugate