Studies on Fluorescent Antibody Staining II. Inhibition by Sub-Optimally Conjugated Antibody Globulins. ∗

Abstract

Summary

1. Three rabbit immune globulin preparations were coupled at 1 or 2% protein concentration with 8 or 10 mg of crystalline FITC per gram of protein. 2. Each preparation was heterogeneous with respect to the number of fluorescent groupings coupled to individual globulin molecules. 3. In these preparations from 35 to 80% of the conjugated globulins contained less than an optimal number of fluorescent groupings. 4. Maximum brightness of specific staining was obtained after each preparation was fractionated on DEAE-cellulose to separate the optimally coupled from the under-coupled and the over-coupled globulins.