Expression of Rift Valley Fever virus antigens in Arabidopsis thaliana for oral consumption

• Rift Valley Fever (RVF) is a viral disease affecting both domesticated ruminants and humans. Since 1931, when the causative agent was first discovered in Kenya [1], there have been several severe outbreaks mostly in Sub-Saharan Africa [2]. RVF is now considered as one of Africa’s most important viral zoonoses and is endemic in large parts of the continent. In recent years, RVF has also emerged into Saudi Arabia and the Yemen, where it now is endemic [3]. Common symptoms of an ongoing RVF infection in humans are influenza-like, although more severe clinical manifestations such as hemorrhagic fever, ocular disease and encephalitis are often observed [4]. Outbreaks in livestock may have large economic impact. The etiological agent, the RVF virus (RVFV), is an enveloped negative sense RNA virus, which belongs to the genus Phlebovirus in the Bunyaviridae family. As the other members of this family, RVFV has three gene segments; the L, M, and S segments. The L segment encodes an RNA-dependent RNA polymerase and the M-segment the glycoproteins and a non-structural protein. By using an ambisense strategy, the S-segment codes for the highly immunogenic nucleocapsid protein (N) and a non-structural protein [4]. The main focus of this project is to establish the plant production of an RVF vaccine candidate, primarily for oral administration. This is an attractive model for vaccination, especially of livestock. The two currently available vaccines for animals are a live attenuated variant, albeit teratogenic, or a weaker inactivated vaccine which requires annual boosters. There is no human vaccine available for general use. Similarly to our previous expression studies with the HIV p24 protein [5-7], the Helicobacter pylori TonB protein [8], and the Chlamydia trachomatis MOMP chimera [9], we have used Agrobacterium tumefaciens-mediated gene transfer to introduce genes encoding RVFV antigens into Arabidopsis thaliana. Transformed model plants have been created that express the full length RVFV N protein or deletion mutants of the two RVF glycoproteins. Analyses of transformants are on-going (PCR for genomic insertion, cDNA synthesis and RT-PCR for mRNA occurrence, and Western blotting for protein production) and in at least some cases have been shown to carry the corresponding recombinant protein. Mice are being fed fresh transgenic A. thaliana and the subsequent immune response towards the N protein and the glycoproteins will be closely monitored and evaluated by neutralisation test, Western blot and ELISA. Thereafter, the mice will be challenged with the wild-type virus and the protective efficacy of the edible vaccine will be determined. References1. Daubney R, Garnham P (1931) J Patol Bacterio 34: 8922-8926; 2. Gerdes G (2004) Rev Sci Tech 23: 613-623; 3. Balkhy H, Memish Z (2003) Int J Antimicrob Agents 21: 153-157; 4. Flick R, Bouloy M (2005) Curr Mol Med 5: 827-834; 5. Lindh, I., Kalbina, I., Thulin, S., Scherbak, N., Sävenstrand, H., Bråve, A., Hinkula, J., Strid, Å. & Andersson, S. (2008) APMIS 116, 985-994; 6. Lindh, I., Wallin, A., Kalbina, I., Sävenstrand, H., Engström, P., Andersson, S. & Strid, Å. (2009) Prot. Expr. Purif. 66, 46-51; 7. Lindh, I., Andersson, S. & Strid, Å. (2010) In vivo 24, 368-370; 8. Kalbina, I., Engstrand, L., Andersson, S. & Strid, Å. (2010) Helicobacter 15, 430-437; 9. Kalbina I., Wallin A., Lindh I., Engström P., Andersson S. & Strid Å. (2011) Prot. Expr. Purif. 80, 194-202.

Ämnesord

LANTBRUKSVETENSKAPER  -- Bioteknologi med applikationer på växter och djur -- Växtbioteknologi (hsv//swe)

AGRICULTURAL SCIENCES  -- Agricultural Biotechnology -- Plant Biotechnology (hsv//eng)

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

Biochemistry

Biokemi

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