Purification and characterization of erythrogenic toxins II. communication: In vivo biological activities of erythrogenic toxin produced by streptococcus pyogenes strain NY-5

Summary Some in vivo biological activities of a purified erythrogenic toxin preparation from strain NY-5 of group A streptococci (ET NY-5) were studied. After intracutaneous administration in a dose of minimally 5 × 10−8 mg, the toxin provoked a skin reaction in old guinea pigs. No skin reaction could be elicited in young adult rabbits. ET NY-5 was pyrogenic for rabbits; the MPD-4 amounted to 0.017 μg/kg intravenously. The pyretic response had a delayed onset and then rose gradually up to hour 5 postinjection. Intravenous administration led to changes in circulating leukocyte counts, viz. brisk acute granulocytopenia and protracted lymphopenia. The method of pyrogenic cross tolerance revealed that ET NY-5 contains two types of pyrogenic exotoxin, A and C.