Date of Award




Document Type


Degree Name

Doctor of Philosophy (PhD)


Department of Biomedical Sciences

Content Description

1 online resource (xvii, 259 pages) : illustrations (some color)

Dissertation/Thesis Chair

Nicholas J Mantis

Committee Members

Nicholas J Mantis, Kathleen McDonough, Christina Egan, Gary Winslow, James R Drake


Biodefense, Ricin, Therapeutics, Toxin, Vaccine, Plant toxins, Vaccines

Subject Categories

Biology | Immunology of Infectious Disease


Ricin is a toxin that is naturally produced by the seeds of the castor bean plant Ricinus communis, and is part of a family of A-B toxins that includes Shiga, cholera, and anthrax toxins. The toxin consists of two subunits, RTA and RTB, which are linked by a disulfide bond. RTA is an RNA N-glycosidase that selectively targets and inactivates 28S ribosomal RNA, thereby arresting protein synthesis and leading to cell death. RTB is a galactose/ N-acetylgalactosamine-specific lectin that mediates attachment, entry, and intracellular trafficking of ricin in host cells. Currently, there is no approved vaccine or therapeutics available against this Category B select agent and the details of toxin neutralization by monoclonal antibodies (mAbs) are still elusive.