Development of monoclonal antibodies against E1 protein of Chikungunya virus.

Chikungunya fever (CF) is a mosquito-borne viral disease caused by Chikungunya virus (CHIKV) that is being increasingly reported in previously non-endemic areas, including Guangdong, China. Despite the low mortality rate associated with CF, some patients may develop chronic joint pain that persists for months or years. Moreover, due to the similarities in symptomatology between CHIKV and other arboviruses, clinical diagnosis without laboratory confirmation is inaccurate. The CHIKV envelope protein E1, critical for viral entry and assembly, is a promising diagnostic and therapeutic target. In this study, we expressed the CHIKV E1 protein in Escherichia coli and developed 16 monoclonal antibodies (mAbs) against E1 to establish an enzyme immunoassay (EIA). The EIA specifically detects CHIKV E1 with no cross-reactivity to other major human-pathogenic arboviruses, including dengue virus (DENV). We evaluated its performance in serum samples of 84 CHIKV-infected patients, with qRT-PCR as the reference standard, and compared it with 93 healthy and 94 DENV-1-infected controls. The assay achieved a sensitivity of 94.05% (95% CI: 87.3-97.3) and a specificity of 98.4% (95% CI: 95.3-99.5). This E1 antigen-based EIA enables rapid and accurate diagnosis of CHIKV infection to facilitate the control of outbreaks of this emerging arbovirus.