It is well known that the urinary tract can also show immunoreaction as a part of the living body. The detection of urinary immunoglobulins is essential for the study of this process. Up to the present, as a detective method a single radial immunodiffusion (SRID) technipue has been usually used after concentrating urine 100-1, 000 fold. But by this method we frequently obtained inaccurate results because of the loss of protein during the course of concentration as well as because of its complexity.
To make up for this defect, we developed Enzyme-linked Immunosorbent Assay (E. L. I. S. A.) technipue using horseradish peroxidase as enzyme, which was easier and more correct. In this paper, we studied utility of this technipue in the detection of urinary immunoglobulins and we detected urinary IgG, IgM, IgA, SIgA and FSC separately in 34 healthy controls.
The detectable range of this method is 10μg to 10mg/dl, so the accuracy does not improve as radioimmunoassay (RI) but becomes much more sensitive them SRID and adequate to the urinary immunoglobulin level. The period needed for detection was 2 days, shorter than that needed for SRID after concentration of urine. Peroxidase reaction held in urine itself was negligible except in severe hematuria. Urinary IgG & IgM were detected with monospecific rabbit antisera in the same way as we did of the serum. Assay of IgA was performed after absorption of the samples with anti SC. FSC was detected after absorption with anti IgA. SIgA was detected with anti SC, based upon the result that the values of SIgA with anti SC as antibody were well correlated (r=0.97) to the values of SIgA using anti SC minus FSC.
The mean of urinary IgG was 352μg/dl; IgM 42g/dl; IgA 122μg/dl; SIgA 90μg/dl and FSC was 35μg/dl. The values were widespread, the standard deviation value being larger than the mean. These data concerning IgG and IgA are not so different from those of Bienenstock, Burdon and Turner. The values of IgG and IgM were strongly correlated, but not to that of SIgA. Thus we thought that these two groups of immunoglobulins were different in the mechanism of presence to the urinary tract.