Expression of the capsid protein of Chikungunya virus in a baculovirus for serodiagnosis of Chikungunya disease

Chikungunya virus (CHIKV) causes endemic or epidemic outbreaks of CHIK fever, which typically manifests as a febrile illness. To develop a CHIKV-specific diagnostic test, CHIKV capsid protein was expressed using a baculovirus expression system. The seroreactvity of the recombinant CHIKV capsid protein was evaluated by ELISA and immuochromatographic assay (ICA), using 40 anti-CHIKV-positive and 20 anti-CHIKV-negative sera, an additional 20 normal sera samples from healthy Koreans, and 20 anti-Dengue virus sera samples. The sensitivity of the recombinant CHIKV capsid protein was 85% and 87.5% as measured by ELISA and ICA, respectively. The specificity of the recombinant CHIKV capsid protein was 100% both by ELISA and by ICA. No cross-reactivity of the capsid protein was seen with anti-Dengue virus sera samples. There was a significant correlation between the ELISA- and ICA-measured seroreactivities of the recombinant CHIKV capsid protein for anti-CHIKV IgM-positive sera samples. These results suggest that the recombinant CHIKV capsid protein could be used in a diagnostic test for identifying CHIKV disease.