Then, 100 l of the previously mentioned antiserum (1:500 dilution) was added and incubated for 2 h at 37C. rise in anti-glycoprotein IgG and IgA antibodies in their serum and feces, respectively. The mice in the fed/boosted group showed a significant rise in specific IgG antibodies after a single boost. Our results imply that oral immunization of animals with edible materials from transgenic plants is feasible, and further assessments are under way. In addition, while the study of CCHF is challenging, our protocol should be further used to study CCHFV infection in the knockout mouse model and virus neutralization assays in biosafety level 4 laboratories. == INTRODUCTION == Crimean-Congo hemorrhagic fever (CCHF) is a frequently fatal disease in humans. The CCHF virus (CCHFV) belongs to Rabbit Polyclonal to GRAK the familyBunyaviridaeand the genusNairovirusand contains a three-segment RNA genome, including S (small), M (medium), SCR7 and L (large) segments which encode a viral nucleoprotein, a precursor SCR7 glycoprotein, and an RNA-dependent RNA polymerase, respectively (18,23). Subsequently, the precursor is matured to GNand GCglycoproteins by proteolytic cleavages (1,41). In addition to transmission via tick bite and nosocomial infections, humans are mainly infected by exposure to the tissue and blood of infected livestock, which are asymptomatic. The virus is widely distributed, with outbreaks and epidemics SCR7 occurring throughout much of Asia, extending from China to the Middle East and southern Russia, and in focal areas of endemicity over much of Africa and parts of southeastern Europe (11,14,25,31). The average case fatality rate ranges from 30 to 50%, but mortality rates from 10% to 80% have been reported during various outbreaks (42,50,52). The current approach to the treatment of CCHF is based on general supportive measures, including monitoring the patient’s hematologic and coagulation status, replacing cells and factors as needed, and administering ribavirin (22,47). Therefore, immunization is considered to be essential in mitigating the high rate of mortality from viral hemorrhagic fevers. It was recently shown that Ebola virus glycoprotein can confer protection in vaccinated mice (26). Similarly, specific antibodies against CCHFV are protective in a suckling mouse animal model (6). A CCHFV DNA vaccine expressing the viral glycoprotein elicits in some vaccinated mice neutralizing antibodies that can be precipitated with radiolabeled viruses (43). Although an inactivated CCHFV vaccine could reduce CCHF outbreaks (36), there is a stigma attached to using attenuated vaccines SCR7 due to a fear of reversion of virulence or possible reversion to wild-type virus (38). Hence, the use of recombinant subunit vaccines renders a remarkable benefit to immunization programs. Transgenic plants have been used for the production of edible vaccines and as delivery vehicles of immunogenic subunits (32). Plant-based vaccines have several advantages: they are SCR7 easily scaled up, the recombinant protein can be transported and stored without the need for a cold chain, processing is simple, and there is no risk of contamination with human pathogens (15,32,33,44). Thus far, studies have shown the efficacy of plant-derived antigens in preventing the onset of disease in animals under experimental conditions and their safety and efficacy in human clinical trials (4,34,46,48). We postulated that the distribution rate of the CCHFV can be decreased using an effective and edible vaccine for animals, preventing both virus reproduction in the animal and subsequent transmission to humans since domestic animals play a critical role in the transmission cycle of the virus (21,50). In this study we utilize both transgenic tobacco leaves and hairy roots (HRs). We evaluate the oral immunogenicity of the CCHFV glycoproteins (GCand GN; here, named G1 and G2) produced by transgenic plants when they are delivered as food to mice. We compared the two different strategies of antigen production with the CCHF vaccine that is presently used for human vaccination in Eastern Europe. We found that oral immunization with transgenic plants producing the.