Immunologic cross-reactivity between antisera to group A, type 12 streptococcal cell membrane and human glomerular basement membrane. The effect of age and carbohydrate content.

Antisera to group A, type 12 streptococcal cell membrane and human glomerular basement membrane was evaluated, by indirect immunofluorescence, on adult and neonatal human kidney sections, before and after carbohydrase treatment. Cleavage of GBM carbohydrate potentiated the reactivity of SCM antisera on adult GBM, but not neonatal GBM which in general showed maximal activity without CHOase treatment. Of 22 sera checked 17 showed positive reactivity versus human GBM. Chemical analyses showed that adult GBM contained more carbohydrate than did neonatal GBM, which may explain the observed masking effect.