Figure 4.
Active immunization of dams with GBS6 protects pups against a lethal dose of each of the 6 group B streptococcus (GBS) serotypes covered by the vaccine. Pups born to dams immunized 3 times with either phosphate-buffered saline (dotted line) or 5 µg of GBS6 (capsular polysaccharide/serotype; straight lines), each with AlPO4, were challenged within 24 hours after birth (day 0) with 105–107 colony-forming units, depending on the serotype. Ratios indicate the number of surviving pups 90 hours after the challenge and the total number of pups tested. Protection by vaccination with GBS6 versus phosphate-buffered saline was statistically significant (P < .0001) for all serotypes.