Nuclease-Resistant Aptamers to Botox and Anthrax Toxins

Bruno, John

Abstract

Botulinum toxin and anthrax are two likely bioweapons of choice in military attacks or terrorism against the United States. As such, effective post-exposure therapies, such as antitoxins, to both agents are required. Operational Technologies (OpTech) has extensive experience in the area of DNA aptamer development for the detection of biowarfare agents and biotoxins via its Senior Scientist. OpTech proposes to team with Prof. James Chambers of the Biochemistry Department at the University of Texas at San Antonio (UTSA). Together, the OpTech-UTSA team will develop 2'-pyrimidine modified nuclease-resistant """"""""shielded"""""""" DNA aptamers by the SELEX process to botulinum toxin (BOTOX) and the three anthrax toxin components (edema factor, lethal factor, and protective antigen). """"""""Shielded aptamers"""""""" are well suited to eventual in vivo therapeutic use and would be of low immunogenicity. In Phase I, OpTech will generate shielded aptamers to several serotypes (at least A, B and E) of BOTOX and will determine their relative binding affinities for the intact """"""""derivative"""""""" toxin as well as the separate heavy (100 kD) and light 50 kD) chains. In Phase II, OpTech will develop and test anti-anthrax toxin component shielded aptamers as well as clone and sequence all promising aptamers reactive against either toxin family. Development of """"""""shielded"""""""" (nuclease-resistant) aptamers as toxin inhibitors with greater affinity than antibodies or other antidotes, in general, guarantees the owner of the technology entry into a growing biodefense market. If successful in this project, OpTech will use the knowledge gained to develop improved inhibitors of other bacterial toxins, such as cholera toxin, as well as snake and spider venoms. The therapeutic market for such products would be immense, because DNA is nontoxic and hypoallergenic (does not induce a significant immune response), thus avoiding """"""""serum sickness"""""""" or anaphylaxis upon secondary use. Such reagents could also be used in environmental biosensors or diagnostic test kits for detection of BOTOX and anthrax toxins in body fluids or environmental samples.