抄録
Intravenous administration of human IgG frequently causes hazardous side effects owing to the molecular aggregation of IgG followed by fixation and activation of complement in vivo. To avoid these unwanted effects, acid treatment are in practice. Chemical modifications of IgG also decrease anticomplementariness, and treatment with β-propiolactone by Stephan et al. has an advantage of longer survival time in vivo than that of enzyme treatment because it gives little change on the molecular weight. However, it is known that chemical treatments such as amidination, benzylation or carbamylation reduces antibody titer. In this study we investigated the anticomplemetary activities and the antibody titers of two lots of commercial preparations of human immunoglobulins treated with β-propiolactone (βP-IgG) to SLO, influenza, measles and diphtheria toxin in comparison with non-treated human immunoglobulins (FII) as well as the pepsintreated immunoglobulin preparation (pep-IgG).
The antibody titers of βP-IgG were almost as equal as those of pep-IgG or FII, although small variations probably due to differences between the original titers of materials (pooled plasma) exist.
The anticomplementary activity of βP-IgG was 12.2 CH50%/50mg which revealed to be about a quarter of that of FII (43.1 CH50%/50mg) and within Kistler's critical value (0.6%/mg), however in comparison with pep-IgG (2.3 CH50%/50mg), it showed 5 times as much anticomplementary activity.
Marked increase in anticomplementary activity was noted during storage of the preparations at 37°C for 4 months, although antibody titers were nearly unchanged.
On the other hand the anticomplementary activity increases less than half in comparison to the above state during storage of the preparations for the same period at 4°C.
