Age effects on the reactivity of antistreptococcal cell membrane antisera to murine glomerular basement membrane. In vitro versus in vivo analysis.

Antisera to the streptococcal cell membrane (SCM) were evaluated for their reactivity to murine glomerular basement membrane (GBM) in four strains of mice. Animals were studied on a daily basis from birth through 3 months and weekly thereafter through 18 months. Paired animals were compared for in vivo binding of antibody versus an indirect fluorescent antibody technique on fresh kidney sections. The findings demonstrated a granular type GBM staining for all anti-SCM which were positive. Nonspecific background staining accompanied most of the indirect fluorescent antibody sections tested while being totally absent for the direct fluorescent test on tissue from in vivo challenge of the primary antibody. The in vitro testing showed tissue from young mice (0-6 days old) to be most reactive, while the strongest reactivity was seen in the age group of 10-20 days for in vivo testing. These cross-reactive antibodies, i.e., GBM-binding anti-SCM, are best evaluated by in vivo methods where tissue is taken 4 days after antiserum injection. Animals of the age range 6-8 weeks were often negative, indicating that this age range selected for many studies may not be the most favorable one via either in vitro or in vivo studies.