Streptococcal Red-cell-sensitizing Antigens

Abstract

IN previous communications the occurrence in streptococcal cultures of a total of 5 serologically distinct red cell sensitizing antigens has been reported^1–3. A further two such antigens have now been identified. These are: (1) An antigen produced by but not exclusively associated with streptococci of Lancefield Group D. (This antigen is being made the subject of a more extensive report.) (2) An antigen produced by streptococci of Lancefield Group O and also by pneumococci. The distribution of this antigen has been particularly examined in extracts of whole streptococcal cells prepared by autoclaving in saline for 20 min at 115° C. The antigen was produced by the NCTC Group O strain 8029, by 9 Group O strains isolated from upper respiratory tract sources and by eight strains of pneumococci. The latter included one strain of each of Types 2, 14 and 16 and five laboratory isolates of unidentified type. The antigen was not produced by representative strains of each of Lancefield Groups A–Q, with the exception of Group O, nor by nine serologically unclassified viridans strains.