Protective efficacy of mouse serum to the N-propionyl derivative of meningococcal group B polysaccharide

Abstract The protective properties of antibodies induced by immunization of mice with a conjugate of tetanus toxoid and the N -propionyl derivative of group B meningococcal polysaccharide ( N -Pr-GBMP-TT) have been investigated. Mice immunized with the conjugate produced antibodies which were bactericidal for Neisseria meningitidis strains B:2b:P1.Ham and B:15:P1.16. Passive protection studies indicated that the conjugate serum completely eliminated or reduced considerably levels of bacteremia by the same strains in mice. There was no bactericidal activity or passive protection against a strain of N. meningitidis C:2b:P1.2. Following absorption of the conjugate serum with GBMP the non-absorbed antibody, directed to N -Pr-GBMP, was bactericidal and protected mice against bacteremia with group B meningococci. Thus N -Pr-GBMP antibodies which do not bind to the GBMP are protective in vitro and in vivo .