Reduction of Nonspecific Background Staining in the Fluorescent Treponemal Antibody-Absorption Test

Abstract

The nonspecific background fluorescence which occurs with the fluorescent treponemal antibody-absorption test for syphilis was found to result from a reaction between serum-treated Treponema pallidum organisms and the conjugated antihuman γ-globulin. It was also shown that β-lipoprotein and albumin were the important contributing factors in human serum. Various dilutions of 2.5% trypsin in phosphate-buffered saline specifically reduced background fluorescence under proper test conditions. By employing a trypsin digestion method, a semiautomated procedure utilizing a visual readout has been postulated as feasible.