The role of easily released substances (ERS) from bacteria in physiologic solution in natural immunity. VI. Induction of opsonins for different genera of bacteria by ERS from Staph. aureus oxford.

ERS obtained from Staph. aureus by mild extraction with physiologic saline solution possess activity of inducing nonspecific opsonins which react with homologous bacteria and with related Gram-negative bacteria. ERS from Staph. aureus weakly stimulated precipitins and antibodies active in passive hemagglutination and induced a marked rise in agglutinin titers especially for the homologous strain and Gram-negative S. typhimurium bacilli. N-acetyl-D-glucosamine absorbed the opsonizing factor for various bacteria with heterologous activity.