Characterization of serum anti-diphtheria antibody activity following administration of equine anti-toxin for suspected diphtheria.

There is a global shortage of equine-derived diphtheria anti-toxin (DAT) for diphtheria treatment. There are few existing data on serum antibody concentrations and neutralizing activity post-treatment to support development of new therapeutics. Antibody concentrations were quantified by ELISA and anti-toxin neutralizing activity by cytotoxicity assay in serum from 4 patients receiving DAT for suspected diphtheria.