Figure 4.
Effect of covalent coupling of CWPS/1 with tetanus toxoid upon activity as an intranasal immunogen: differential between antibody response and protection against colonization. Mice (n=7–16 per group) were vaccinated twice at a 1-week interval with 20 μg of CWPS/1 coupled to tetanus toxoid or the uncoupled CWPS/1; 1 μg of cholera toxin (CT) was used as adjuvant. At 3 weeks post-immunization, blood samples were taken for determination of serum antibody to CWPS/1 without and with inhibition with phosphocholine. Shown are geometric mean titers +/− 50 μg PCho/ml. At four weeks post immunization, mice were challenged intranasally with pneumococcus type 6B strain 0603, and nasopharyngeal carriage was determined one week later. Dashed line represents the lower limit of detection.