Recombinant Chikungunya Envelope Protein E2 (strain SL-CK1) (C446-GRP)

Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that causes epidemics globally and has been declared a notable disease by the Centers for Disease Control and Prevention1, 2. Symptoms include high fever, myalgia, rash, and severe polyarthritis which can persist for long after acute infection. CHIKV is an enveloped virus with an 11.8-kb single-stranded, positive-sense RNA genome with two open reading frames3, 4. There are three main genotypes, having 95.2 to 99.8% amino acid identity: Asian, West African, and East/Central/South African (ECSA). The mature CHIKV virion is comprised of a nucleocapsid protein C and two glycoproteins, E1 and E2 5. E1 participates in virus fusion. E2 functions in attachment to cells. E1 and E2 form 80 trimeric spikes on the virus surface6. E2 localizes to the top of the spike and contains three domains: N-terminal domain A (center), domain B (tip), and C-terminal domain C (proximal to the viral membrane)5. The SL-CK1 CHIKV strain was isolated from an epidemic in Sri Lanka in 2007 from a human source and has been fully sequenced (Genbank ID HM045801.1)7. Residue 18 of strain SL-CK1 E2 is a histidine8. This residue is an important determinant of virus fitness in mosquito cells. Soluble recombinant CHIKV E2 protein has been used to generate monoclonal antibodies5.