Immunochemical cross-reactions between type III group B Streptococcus and type 14 Streptococcus pneumoniae

Area of Science:

• Immunology
• Microbiology
• Bacterial Pathogenesis

Background:

• Serological cross-reactions between different bacterial species can complicate accurate identification and diagnosis.
• Previous reports indicate cross-reactivity between certain streptococci and Streptococcus pneumoniae serotypes.

Purpose of the Study:

• To investigate and detail the serological cross-reactivity between group B Streptococcus type III (GBS III) antigens and Streptococcus pneumoniae type 14 (Pn 14) polysaccharide.
• To determine if the cross-reacting antigens are identical.

Main Methods:

• Hot HCl extraction of GBS III antigens.
• Immunodiffusion and immunoelectrophoresis techniques.
• Precipitation of antigens using type-specific GBS III antisera and pneumococcal omniserum.

Main Results:

• GBS III and Pn 14 antigens exhibited similar electrophoretic migration patterns, migrating towards the cathode.
• All other tested pneumococcal polysaccharides migrated towards the anode.
• Lines of identity in immunodiffusion confirmed cross-reactivity between GBS III antisera and Pn 14 antiserum with the respective antigens.
• No cross-reactions were observed between GBS III antisera and 11 other pneumococcal types.

Conclusions:

• The cross-reacting antigens of GBS III and Pn 14 are immunologically identical.
• This immunological identity explains the observed serological cross-reactivity between these bacterial types.