Immunogenicity of Staphylococcus aureus delta-toxin.

Studies were conducted to determine the immunogenicity of purified Staphylococcus aureus delta-toxin. Rabbits and guinea pigs immunized with delta-toxin incorporated into a multiple antibody, whereas animals given toxin in saline or toxin in saline with Tween 80 did not produce antibody. The immunoglobulin G (IgG) fraction isolated by chromatography on protein A-Sepharose was examined for the presence of anti-delta-toxin antibody by immunoelectrophoresis, immunodiffusion, quantitative precipitation tests, affinity chromatography, and toxin neutralization tests. Although delta-toxin-specific IgG precipitated the toxin in agar gels, the antibody did not neutralize the toxin's hemolytic activity. Delta-toxin binding to human erythrocyte membranes was demonstrated by indirect immunofluorescent staining of toxin-treated erythrocytes.