IMPROVED STANDARDIZATION IN THE QUANTITATIVE ESTIMATION OF SOLUBLE IMMUNE-COMPLEXES MAKING USE OF AN INTERNATIONAL REFERENCE PREPARATION - RESULTS OF A COLLABORATIVE MULTICENTER STUDY

  • 1 January 1984
    • journal article
    • research article
    • Vol. 58  (2) , 502-509
Abstract
Heat aggregated IgG (A-IgG) of restricted size and complement solubilized tetanus toxoid (Te); human anti-Te immune complexes (IC) were sent as coded test samples to 8 laboratories for quantitative assessment by different IC assay techniques including complement C 1q solid and fluid phase binding assays, conglutinin binding assay, Raji cell test and particle counting immunoassay. Samples containing the same material at concentrations communicated to the laboratories for the performance of reference curves were included. The investigators were asked to estimate the quantity of A-IgG or Te:aTe in the coded samples by reference to both their own locally produced standards and to the A-IgG and Te:aTe reference preparations of known concentrations. When calculated on the basis of locally prepared standards the range of concentrations found by the various laboratories and tests was 20-260 .mu.g/ml for A-IgG (actual concentration 50 .mu.g/ml) and 32-1420 .mu.g/ml for Te:aTe complexes (actual concentration 40 .mu.g complexed antibody/ml). When read on the international candidate reference A-IgG preparation these ranges were 28-800 .mu.g/ml and 35-800 .mu.g/ml, respectively. The highest standardization efficiency was obtained when the Te:aTe reference curve was used for quantitation; the range of results obtained for A-IgG and Te:aTe coded samples being as narrow as 7-40 .mu.g/ml and 34-68 .mu.g/ml, respectively. Thus, when the content of the coded samples was estimated on the basis of the Te:aTe reference curves established in the laboratories a narrow clustering of the results was seen. It is proposed that the Te:aTe preparation, which has been found stable during storage for 2 yr, could serve as a useful international reference preparation in the field of IC determination.