Anti-polysaccharide immunoglobulin isotype levels and opsonic activity of antisera: relationships with protection against Streptococcus pneumoniae infection in mice

J Infect Dis. 1995 Aug;172(2):562-5. doi: 10.1093/infdis/172.2.562.


Relationships between in vitro parameters (opsonic activity and anti-pneumococcal polysaccharide [PS] antibody subclasses) and in vivo mouse protection were established by logistic regression analysis. Data were from 158 mice challenged with pneumococci after vaccination with synthetic oligosaccharide- and PS-protein conjugates in combination with the adjuvant Quil A. The hypothesis that serum opsonic activity has predictive value for protection against pneumococcal infection was tested. Serum opsonic activity was well correlated with protection (chi 2 = 35.5, P < 0.001), although a stronger correlation was observed for anti-PS IgM and IgG. The combined use of IgG and opsonic activity as predictor variables yielded the best fitting model for predicting protection (chi 2 = 74.1, P < 0.001). When opsonic activity data were added to models that included various antibody isotypes, the statistical significance of the models was enhanced. Thus, the opsonic activity of antisera induced by pneumococcal vaccines can predict mouse protection.

MeSH terms

  • Adjuvants, Immunologic
  • Animals
  • Antibodies, Bacterial / blood*
  • Antigens, Bacterial / immunology
  • Bacterial Vaccines / immunology
  • Female
  • Immunoglobulin Isotypes / blood*
  • Mice
  • Mice, Inbred BALB C
  • Opsonin Proteins / blood
  • Pneumococcal Infections / immunology
  • Pneumococcal Infections / microbiology
  • Pneumococcal Infections / mortality
  • Polysaccharides, Bacterial / immunology
  • Streptococcus pneumoniae / immunology*


  • Adjuvants, Immunologic
  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Bacterial Vaccines
  • Immunoglobulin Isotypes
  • Opsonin Proteins
  • Polysaccharides, Bacterial
  • pneumococcal polysaccharide type 17F