Anti‐hapten antibodies in normal sera

Abstract Many normal human, rabbit and reindeer sera were found to inactivate bacteriophages coupled with synthetic haptens NIP (4‐hydroxy‐3‐iodo‐5‐nitrophenylacetic acid), NP (hydroxy‐3‐nitrophenylacetic acid), DNP (2,4‐dinitrophenol), oxazolone (2‐phenyl‐4‐ethoxy methylene oxazolone) or penicillin G. Evidence was produced indicating that these inactivators are antibodies with specificities roughly as strict as those of early immune antibodies. While most of the phage‐inactivation power was due to 19 S antibodies, 7 S inactivators with chromatographic characteristics of IgG were demonstrated. There were great inter‐individual differences in various anti‐hapten titers. In spite of that, inter‐species differences could also be demonstrated.