DEMONSTRATION OF THE NON-IDENTITY BETWEEN THE FC RECEPTOR FOR HUMAN-IGG FROM GROUP-A STREPTOCOCCI TYPE-15 AND M PROTEIN, PEPTIDOGLYCAN AND THE GROUP-SPECIFIC CARBOHYDRATE

  • 1 January 1979
    • journal article
    • research article
    • Vol. 87  (3) , 257-261
Abstract
After electrophoresis of an alkaline extract of type 15 group A streptococci, 3 main precipitation lines were obtained in diffusion experiments against commercial human polyclonal Ig[immunoglobulin]G (lines 1, 2 and 3). Of 23 sera, 19 (83%) from apparently healthy human individuals gave line 3, while 6 of them (26%) gave line 1. The sera giving line 1 gave line 3. Line 2 was obtained with 2 sera only, also giving lines 1 and 3. Line 3 was caused by a streptococcal Fc-receptor for human IgG since the line could be displaced by addition of Fc fragments, but not Fab fragments of pooled human IgG. Line 1 was different from line 3, since line 1 was suppressed in contrast to line 3 on absorption of a human serum or commercial polyclonal human IgG with Staphylococcus aureus and line 1 was suppressed by Fab fragments but not Fc fragments of polyclonal human IgG. Line 2 could be inhibited by addition of peptidoglycan to commercial polyclonal human IgG or a human serum investigated. Line 4, obtained in diffusion experiments involving electrophoretically separated alkaline extract of type 15 group A streptococci, was type-specific as shown by rabbit antisera to streptococci type M1, M8, M15 and T44, and disappeared on trypsinization of the extract. The component responsible for line 4 in the streptococcal extract, judged to be type-specific M protein, had a mobility different from the component responsible for line 3 in electrophoresis.