[Distribution of IgG subclasses and their biological activity in bioglobulin]

Abstract

Preparations of human immunoglobulin for intravenous use (IVIG) should contain proper percentage of IgG subclasses, corresponding to physiological proportions with preserved activity of antibodies. The amounts of IgG subclasses were determined using the radial immunodiffusion technique against to the WHO reference serum 67/97. It appears that variations are observed among the different lots and manufacturers of the various formulations of IVIG available in Poland. Although some of these differences are not statistically significant, significant differences in subclass concentrations were found between formulation of IVIG, with Bioglobulina being lower in IgG1 and higher in IgG2 and Endobulin having a lower per cent of IgG3. The study was aimed at establishment of activity values against diphtheria and tetanus toxoids and Streptococcus group B (GBS). IgG antibodies to tetanus and diphtheria toxoid antigens were predominantly of the IgG1 and IgG2 isotype. IgG4 subclass, was present in smaller proportion and IgG3 fractions was absent. Antibodies to GBS were only IgG2 and IgG1 isotypes. Basing on obtained results it can be stated that in spite of the imbalance between the amounts of IgG1 and IgG2 in Bioglobulina, the activity which was determined in subclasses is comparable with that of other IVIGs.