Efficacy of intravenous immunoglobulin preparations against viral and bacterial infections in mouse protection tests.

Our investigation indicates that pretreatment of human immunoglobulin for the elimination of the anticomplementary activity is associated with a loss of activity, the extent of which depends on the type of treatment applied. Laboratory preparations of human IgG were tested in a mouse protection assay using influenza A2-Taiwan virus, tetanus toxin and Salmonella typhimurium as the challenge. There was a 7-28% reduction in efficacy in an intravenous 7S preparation in comparison with an untreated 7S IgG. F(ab')2 fragments showed a 24-65% and Fab fragments an 80-100% reduction in efficacy. Two commercial human 7S products showed approximately 90% efficacy in the Salmonella assay; a commercial, pepsin-treated preparation showed 65-74% efficacy when compared with untreated 7S IgG.