Varying titers of neutralizing antibodies to streptococcal superantigens in different preparations of normal polyspecific immunoglobulin G: Implications for therapeutic efficacy

Abstract

In as much as normal intravenous polyspecific immunoglobulin G (IVIG) neutralizes the activity of a wide spectrum of superantigens, it may be an efficient adjunctive therapy for diseases associated with superantigen- producing organisms, including severe group A streptococcal diseases. The neutralizing activity against purified superantigens, streptococcal pyrogenic exotoxin.s (Spe), and a mixture of superantigens present in culture supernatant of clinical group A streptococcal isolates was determined for five IVIG preparations. A significant variation among different IVIG preparations (P < .05) and different lots of the same IVIG brand (P < .044) was found. Neutralization of SpeA activity was significantly lower than that of other streptococcal superantigens (P