Review 10.1586/14760584.5.6.839 © 2006 Future Drugs Ltd ISSN 1476-0584 839 www.future-drugs.com Chloroplast- derived anthrax and other vaccine antigens: their immunogenic and immunoprotective properties Sushama Kamarajugadda and Henry Daniell † † Author for correspondence Department of Molecular Biology and Microbiology, University of Central Florida, Bimolecular Science Building 20, room 336, Orlando, FL 32816–2364, USA Tel.: +1 407 823 0952 Fax: +1 407 823 0956 daniell@mail.ucf.edu KEYWORDS: anthrax vaccine, chloroplast genetic engineering, genetically modified crops, immunization, mucosal immunity, oral delivery, protective antigens, systemic immunity, vaccines Transgenic plants offer many advantages, including low cost of production (by elimination of fermenters), storage and transportation, heat stability, absence of human pathogens, protection of antigens in the stomach through bioencapsulation (when delivered orally), elimination of the need for expensive purification and sterile injections and generation of both systemic and mucosal immunity. Recent studies have demonstrated that chloroplast- derived anthrax-protective antigen elicits effective immune responses, develops neutralizing antibodies, confers complete protection against anthrax lethal toxin challenge and produces 360 million doses of vaccine in one acre of transgenic plants. Chloroplast-derived vaccine antigens are efficacious against bacterial, fungal, viral and protozoan pathogens. Expert Rev. Vaccines 5(6), 839–849 (2006) T he concept of vaccination discovered by Edward Jenner in 1796 has helped mankind in fighting against many infectious diseases. We have come a long way in global eradication of deadly diseases, such as small pox, polio and measles. T he daunting challenge of fighting against emerging infectious diseases can be met by further advancements in vaccine development. Although it has been 200 years since its discovery, vaccine development needs continuous improvement. Many ele- ments must be considered for an effective vaccine development. A vaccine must: • Elicit protective immunity against an infection; • Be potent enough even at lower doses so that it can be practical and affordable; • Be safe and not cause any side effects; • Be stable and retain its functional efficacy starting from production, transport, storage to the time of delivery into the host; • Be able to elicit both humoral and cell medi- ated immunity depending on the type of organism; • Be able to elicit long term immune response with few booster doses; • Be cost effective [1]. None of the current vaccines meet all of these criteria. The conventional method of producing vaccines using whole or partial components of the organism, whether dead or alive, has raised concerns regarding their safety and efficacy. T he need for larger populations at lower costs demands alternative approaches for vac- cine production. For example, hundreds of millions of people living in developing coun- tries are infected with Hepatitis, but the daily income of a third of the world population is less than US$2 per day [2]. With the onset of recombinant gene technologies, the vaccine industry has revolutionized the production of vaccines in more effective expression systems that are safer, cheaper and provide protection to the host organisms against bacterial, viral or other pathogens [1]. Among the various expres- sion systems, plants are increasingly recognized as a safe and inexpensive system for the CONTENTS Chloroplast-derived bacterial vaccine antigens Chloroplast-derived viral vaccine antigens Chloroplast-derived protozoan vaccine antigens Expert commentary & five-year view Key issues References Affiliations For reprint orders, please contact: reprints@future-drugs.com