Abstract
Rabbit antisera to "carbohydrate-rich" antigens prepared from group-A, type-12 streptococcal cell-membrane and human glomerular basement-membrane were found to react by an indirect fluorescent-antibody test with the glomerular basement membrane of adult human kidney. This activity was absent or diminished in neonatal tissue. Removal of the carbohydrate epitopes from the adult tissue by means of carbohydrases removed the immunological activity. Antisera against the "carbohydrate-rich" antigens showed immunological reactivities distinctly different from those against the parent native immunogens--streptococcal cell membrane or glomerular basement membrane--which proved to be directed towards the portein epitopes.