116. Potency of a Human Monoclonal Antibody to Diphtheria Toxin Relative to Equine Diphtheria Anti-toxin in an Animal Model Heidi Smith, MD, PhD; Peter Cheslock, PhD; Mark Leney, PhD; Bruce Barton, PhD; Deborah Molrine, MD; MassBiologics of the University of Massachusetts Medical School, Boston, Massachusetts; Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, ...