Development of an Avian Antitoxin to Type A Botulinum Neurotoxin
Most commercially available antitoxins and antivenoms are raised in horses and purified by bulk fractionation techniques. These preparations frequently elicit deleterious side effects that compromise their efficacy and the treatment of intoxication or envenomation. Alternatively, the use of hyperimmune immunoglobulin from the egg yolks of laying hens has shown considerable promise as a cost-effective and potentially safer source of antitoxins and antivenoms. To investigate the utility of this system in the development of a botulism antitoxin, laying hens were immunized with purified 150 kDa type A botulinum neurotoxin detoxified with formaldehyde. Antibodies present in egg yolk were then isolated by polyethylene glycol (PEG) fractionation and further purified by affinity chromatography using immobilized toxoid. These antibodies exhibited a high titer of toxoid reactivity as measured by enzyme immunoassay. A mouse lethality/protection assay demonstrated the efficacy of these antibodies in neutralizing type A botulinum neurotoxin, where PEG-fractionated and affinity-purified antibodies neutralized 38 and 340 I.U. of type A botulinum neurotoxin per milligram of protein, respectively. Thus, the avian antibody preparations, even if only PEG-fractionated, are significantly more potent (neutralization titer per mg protein) than conventional equine botulism antiserum preparations. In addition to their superior potency, hyperimmune avian antibodies, whether PEG-fractionated or affinity-purified, are expected to significantly increase antitoxin safety.
KeywordsBotulinum Neurotoxin Serum Sickness Neutralization Titer Infant Botulism Connaught Laboratory
Unable to display preview. Download preview PDF.
- 1.Hatheway CL. Toxigenic clostridia. Clinical Microbiol Review 1990; 3: 66–98.Google Scholar
- 3.World Health Organization. Progress in the characterization of venoms and standardization of antivenoms. WHO Offset Publication No. 58. Geneva, 1981.Google Scholar
- 4.Botulism Antitoxin, Trivalent (Equine) Types A, B, and E; Connaught Laboratories package insert.Google Scholar
- 6.Schwartz PJ, Amon SS. 1992. Botulism immune globulin for infant botulism arrives–one year and a Gulf War later. West J Med 1992; 156: 197–198.Google Scholar
- 10.Carroll SB. Antivenoms and methods for making antivenoms. U.S. Patent Application (pending ) 1989.Google Scholar
- 14.Poison A, von Wechmar MB, van Regenmortel MHV. Isolation of viral IgY antibodies from yolks of immunized hens. Immunol Comm 1980; 9: 475–493.Google Scholar
- 16.Cardella MA. Botulinum toxoids. In: Lewis KH, Cassel K Jr, eds. Botulism: Proceedings of a symposium PHS Publication No. 999-FPI, Washington, D.C.: Government Printing Office 1964: 113–130.Google Scholar
- 17.Reed Li, Muench H. A simple method of estimating 50% endpoints. Amer J Hyg 1938; 27: 493–497.Google Scholar
- 18.The United States Pharmacopeia, Twenty-second Revision. (United States Phannacopeial convention, Inc. Rockville, MD.) 16th edition, 1990: 186.Google Scholar