Establishment of rabbit model for immunogenicity evaluation of pneumococcal conjugate vaccine

Objective To establish an animal model for evaluating immunogenicity of pneumococcal conjugate vaccine. Methods New Zealand rabbits were intramuscularly administrated with three doses of 13-valent pneumococcal conjugate vaccine (PCV13) with two weeks interval between each injection. Serum samples were collected at different time points before and after vaccination. Quantitative enzyme-linked immunosorbent assay (ELISA) and opsonophagocytosis assay (OPA) that were in conformity with the World Health Organization (WHO) standards were used to detect the concentrations of serotype-specific antibodies and their bactericidal activities. Results The concentrations (Geometric mean concentration, GMC) of serotype-specific antibodies in rabbit serum samples were well correlated with their bactericidal activities (Geometric mean titer, GMT) following vaccination. Moreover, the dynamic changes of GMC and GMT of the same serotype-specific antibody remained consistent as time went by. Conclusion Rabbit model can be used to analyze the immunogenicity of PCV13 vaccine with quantitative ELISA and OPA, which indicates that it is a suitable animal model for evaluating immunogenicity of pneumococcal conjugate vaccine. Key words: Rabbit model; Enzyme-linked immunosorbent assay (ELISA); Opsonophagocytosis assay (OPA); Immunogenicity; 13-valent pneumococcal conjugate vaccine (PCV13)