The Journal of Medical Microbiology, Vol 12, Issue 2 177-185, Copyright © 1979 by Society for General Microbiology
Inhibitors in urine of radioimmunoassay for the detection of gonococcal antigens
M. J. Thornley, M. G. Andrews, J. O. Briggs and B. K. Leigh
Several substances in urine were found to inhibit the radioimmunoassay of
added gonococcal antigens. The supernatants of two-thirds of urine samples
from male patients with either gonorrhoea or non-specific urethritis (NSU)
were inhibitory. The inhibition caused by many, but not all, samples was
reduced or completely abolished by the addition of soybean trypsin
inhibitor (STI); STI-sensitive inhibition is thought to be due to
proteolytic enzymes, probably from pus cells. Their inhibitory effect was
shown to be due to their action on gonoccocal antigens and not on
antibodies in the assay system. Some supernatants contained other
inhibitors unaffected by STI; some of these were dialysable and others were
not. Sediments from the urine of patients with NSU or gonorrhoea were often
strongly inhibitory, but treatment with STI annulled all but very slight
inhibition. STI-treated sediments could, therefore, be used in an assay
designed to detect gonococcal antigens.
