Protective activity of two human intravenous immunoglobulin preparations in experimental infection with an encapsulated Staphylococcus aureus strain.

: The protective effect of two different human immunoglobulin preparations for intravenous use and one specific staphylococcal immunoglobulin for intramuscular application were compared in mice infected with the capsular Staphylococcus aureus Smith strain. Immunovenin is produced by partial fragmentation of IgG with plasmin; it contains about 60% intact IgG and 40% Fab and Fc fragments. Immunovenin-intact is produced by a polyethylene glycol (mol wt 6000) fractionation method followed by ion exchange chromatography and contains more than 95% intact IgG molecules. A specific staphylococcal immunoglobulin is obtained by a rivanol/ethanol fractionation method from selected sera with high anti-alpha toxin level. All three types of immunoglobulins induced similar degree of protection when their effect was determined as activity (ED50) per gram immunoglobulin.