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[Guest guest]

This is amazing: the cost of vaccine made this way would be miniscule:

360 M doses from one acre of tobacco! I'm not claiming it would be

safe, but it would certainly be a lot " cleaner " than what is available

now. BTW, This article is freely accessible in full text at:

http://iai.asm.org/cgi/reprint/73/12/8266

Meryl

Infect Immun. 2005 Dec;73(12):8266-74.

Plant-based vaccine: mice immunized with chloroplast-derived

anthrax protective antigen survive anthrax lethal toxin challenge.

Koya V, Moayeri M, Leppla SH, l H.

Dept. Molecular Biology & Microbiology, Biomolecular Science Bldg

20, Room 336, University of Central Florida, Central Florida Blvd.,

Orlando, FL 32816-2364, USA.

The currently available human vaccine for anthrax, derived from the

culture supernatant of Bacillus anthracis, contains the protective

antigen (PA) and traces of the lethal and edema factors, which may

contribute to adverse side effects associated with this vaccine.

Therefore, an effective expression system that can provide a clean,

safe, and efficacious vaccine is required. In an effort to produce

anthrax vaccine in large quantities and free of extraneous bacterial

contaminants, PA was expressed in transgenic tobacco chloroplasts by

inserting the pagA gene into the chloroplast genome. Chloroplast

integration of the pagA gene was confirmed by PCR and Southern

analysis. Mature leaves grown under continuous illumination contained

PA as up to 14.2% of the total soluble protein. Cytotoxicity

measurements in macrophage lysis assays showed that chloroplast-derived

PA was equal in potency to PA produced in B. anthracis. Subcutaneous

immunization of mice with partially purified chloroplast-derived or B.

anthracis-derived PA with adjuvant yielded immunoglobulin G titers up

to 1:320,000, and both groups of mice survived (100%) challenge with

lethal doses of toxin. An average yield of about 150 mg of PA per plant

should produce 360 million doses of a purified vaccine free of

bacterial toxins edema factor and lethal factor from 1 acre of land.

Such high expression levels without using fermenters and the

immunoprotection offered by the chloroplast-derived PA should

facilitate development of a cleaner and safer anthrax vaccine at a

lower production cost. These results demonstrate the immunogenic and

immunoprotective properties of plant-derived anthrax vaccine antigen.

Meryl Nass, MD

Mount Desert Island Hospital

Bar Harbor, Maine 04609

207 288-5081 ext. 220