John (Jed) Weldon

Assistant Professor


Contact Information

Smith Hall, Room No. 267


2000 B.A., Biology St. Mary’s College of Maryland

2006 Ph.D., Biology Johns Hopkins University

Areas of Expertise

I have expertise in molecular biology, biochemistry, & biophysics

I primarily study the control of translation by bacterial toxins and the use of toxin conjugates as biological therapeutics for cancer.


I am broadly interested in protein function and behavior at a molecular level, and how we can manipulate the behavior of proteins through directed engineering and external modulators. My research uses techniques from molecular biology, biochemistry, and cell biology to examine the control of protein synthesis by bacterial toxins.

I am particularly interested in the intracellular trafficking of Pseudomonas exotoxin A (PE) and PE-based toxin conjugates, the unique diphthamide target of PE, and the use of conjugate molecules therapeutically.


Weldon JE, Skarzynski M, Therres JA*, Ostovitz JR*, Zhou H, Kreitman RJ, and Pastan I. (2015) Designing the Furin-Cleavable Linker in Recombinant Immunotoxins Based on Pseudomonas Exotoxin A. Bioconjug Chem. 26(6):1120-8.

Weldon JE, Xiang L, Zhang J, Beers R, Walker DA, Onda M, Hassan R, and Pastan I. (2013) A recombinant immunotoxin against the tumor-associated antigen mesothelin reengineered for high activity, low off-target toxicity, and reduced antigenicity. Mol Cancer Ther. 12(1):48-57.

Mazor R, Vassall AN, Eberle JA, Beers R, Weldon JE, Venzon DJ, Tsang KY, Benhar I, and Pastan I. (2012) Identification and elimination of an immunodominant T cell epitope in recombinant immunotoxins based on Pseudomonas exotoxin A. Proc Natl Acad Sci U S A. 109(51):E3597-603.

Liu W, Onda M, Kim C, Xiang L, Weldon JE, Lee B, and Pastan I. (2012) A recombinant immunotoxin engineered for increased stability by adding a disulfide bond has decreased immunogenicity. Protein Eng Des Sel. 25(1):1-6.

Weldon JE and Pastan I. (2011) A guide to taming a toxin: recombinant immunotoxins constructed from Pseudomonas exotoxin A for the treatment of cancer. FEBS J. 278(23):4683-700.

Pastan I, Onda M, Weldon J, Fitzgerald D, and Kreitman R. (2011) Immunotoxins with decreased immunogenicity and improved activity. Leuk Lymphoma. 52 Suppl 2:87-90.

Onda M, Beers R, Xiang L, Lee B, Weldon JE, Kreitman RJ, and Pastan I. (2011) Recombinant immunotoxin against B-cell malignancies with no immunogenicity in mice by removal of B-cell epitopes. Proc Natl Acad Sci U S A. 108(14):5742-7.

Courses Taught

  • Fall:     BIOL 409 Molecular Biology

  • Spring: CHEM 351 Biochemistry I

                CHEM 356 Biochemistry Laboratory