Sera from patients with high titers of antibody to streptolysin O react with listeriolysin

Sera of patients with suspected rheumatic fever and elevated titers of antibody to streptolysin O were examined by an immunoblotting technique. All but two serum samples, which yielded relatively low titers, bound to a 60-kilodalton protein in the supernatant from a culture of Listeria monocytogenes, which presumably represents the listeriolysin.