Immune response of healthy women to 2 different group B streptococcal type V capsular polysaccharide-protein conjugate vaccines.
BACKGROUND
Infections caused by group B streptococcal (GBS) type V are increasingly common. Capsular polysaccharide (CPS)-protein conjugate GBS vaccines are immunogenic in healthy adults, but type V vaccines have not previously been tested.


METHODS
Thirty-five healthy, nonpregnant women were randomized to receive an intramuscular dose of GBS type V CPS-tetanus toxoid (TT) vaccine (n=15), GBS type V CPS-cross-reactive material (CRM(197)) conjugate vaccine (n=15), or placebo (n=5) (double-masked design). Levels of serum antibodies to type V CPS were measured by ELISA, and functional activity was measured by opsonophagocytosis.


RESULTS
The vaccines were well tolerated. Significant increases in type V CPS-specific immunoglobulin G (IgG) were elicited by both vaccines, peaking at 4-8 weeks and persisting for 26 weeks. Four-fold or greater increases in type V CPS-specific IgG concentrations were noted in postimmunization serum samples obtained from 93% of subjects in each vaccine group. These concentrations persisted in > or =85% of conjugate-vaccine recipients 104 weeks later. Type V CPS-specific immunoglobulin M was a dominant isotype of immune response to each conjugate. Postimmunization serum samples promoted opsonophagocytic killing of GBS type V in vitro, whereas those from placebo recipients did not.


CONCLUSIONS
GBS type V conjugate vaccines are safe and immunogenic and would be appropriate for inclusion in a candidate multivalent GBS vaccine.
Section of Infectious Diseases, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA. cbaker@bcm.tmc.edu
Carol J
CJ
Baker
Lawrence C
LC
Paoletti
Marcia A
MA
Rench
Hilde-Kari
HK
Guttormsen
Morven S
MS
Edwards
Dennis L
DL
Kasper
D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D016667:Bacterial Capsules / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007114:Immunization; D007074:Immunoglobulin G / Q000097:blood; D008875:Middle Aged; D022541:Streptococcal Vaccines / Q000276:immunology*; D013292:Streptococcus agalactiae / Q000276:immunology*; D013745:Tetanus Toxoid / Q000276:immunology; D018074:Vaccines, Conjugate / Q000276:immunology
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G; D022541:Streptococcal Vaccines; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate; C028581:CRM197 (non-toxic variant of diphtheria toxin)