Use of animal testing for evaluating glycoconjugate vaccine immunogenicity.

Most animal species respond with high antibody levels to polysaccharide antigens after they have been covalently linked to a protein carrier, converting a T-cell independent to a T-cell dependent antigen. This chemical modification has enabled the development of glycoconjugate vaccines for Haemophilus influenzae type b, Neisseria meningitidis, and multivalent Streptococcus pneumoniae. This new generation of vaccines can be well characterized physically and chemically to ensure consistent vaccine manufacture. Such analytical tests provide an alternative to animal models for Quality Control Laboratories; biological models can be difficult and costly to develop and use on a routine basis. If animal tests are used, they need to be refined, defined, and validated for their intended purpose.