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Use of capsular polysaccharide-tetanus toxoid conjugate vaccine for type II group B Streptococcus in healthy women

C J Baker1, L C Paoletti, M A Rench

  • 1Dept. of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA. cbaker@bcm.tmc.edu

The Journal of Infectious Diseases
|September 9, 2000
PubMed

Insights

Developing a new Group B Streptococcus (GBS) vaccine, researchers found that coupling type II capsular polysaccharide (II CPS) to tetanus toxoid (TT) significantly boosted immune responses in women.

Area of Science:

  • Immunology
  • Vaccinology
  • Microbiology

Background:

  • Group B Streptococcus (GBS) causes significant invasive disease, with type II capsular polysaccharide (II CPS) accounting for an estimated 15% of cases.
  • Developing a multivalent vaccine requires effective GBS serotype conjugates for enhanced immunogenicity.

Purpose of the Study:

  • To evaluate the immunogenicity and safety of a novel conjugate vaccine composed of type II GBS capsular polysaccharide (II CPS) covalently linked to tetanus toxoid (TT).
  • To assess the dose-dependency and correlate immune responses with in vitro opsonophagocytosis.

Main Methods:

  • A pentavalent vaccine strategy involved direct, covalent coupling of II CPS to TT via reductive amination.
  • Two clinical trials involved 75 healthy nonpregnant women randomized to receive either II CPS-TT conjugate or uncoupled II CPS vaccine across a dose range.
  • Immune responses (IgG, IgM, IgA) and opsonophagocytic activity were measured post-immunization.

Main Results:

  • Both II CPS-TT conjugate and uncoupled II CPS vaccines were well tolerated.
  • II CPS-specific IgG, IgM, and IgA serum concentrations peaked two weeks after immunization, with significantly higher levels in recipients of the conjugated vaccine.
  • Immunological responses to the conjugate vaccine demonstrated a dose-dependent effect and correlated with enhanced opsonophagocytosis in vitro.

Conclusions:

  • The II CPS-TT conjugate vaccine is safe and elicits a significantly stronger immune response compared to the uncoupled II CPS vaccine.
  • The dose-dependent immunogenicity and correlation with opsonophagocytosis support the inclusion of the II CPS-TT conjugate in a multivalent GBS vaccine formulation.

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