Immunological cross-reactivity of beta haemolytic streptococci of Lancefield groups A, B, C and G
Mondkar, A.D.
Indian Journal of Medical Research 75: 778-785
1982
ISSN/ISBN: 0019-5340 PMID: 6752009 Document Number: 185646
Clinical isolates (500) of .beta.-hemolytic streptococci were Lancefield-grouped by counter-electrophoresis using acid hydrolysis extracts and sera of groups A, B, C and G. Cross-reactions were observed in as many as 156 of 405 groupable strains (38.5%); maximum with group B strains (33 of 55, 60%) and least with group G strains (14 of 42, 33.3%). Electro-immunodiffusion and antigen-antibody crossover electrophoresis of extracts of standard strains and homologous antisera showed the occurrence of 2 antigens besides the dominant group antigen. Polyacrylamide gel disc electrophoresis of each group extract followed by immunodiffusion against homologous and heterologous group sera indicated the occurrence of 3 distinct antigens. The group-specific antigen was dominant and electrophoretically fast-moving and similar in extracts of groups A, C and G. The group B antigen was electrophoretically slow-moving. The other 2 antigens which were common to all 4 groups, occurred variably in wild strains and were responsible for the cross-reactivity.