In vitro and in vivo efficacy of anti‐chikungunya virus monoclonal antibodies produced in wild‐type and glycoengineered Nicotiana benthamiana plants

Summary Chikungunya virus ( CHIKV ) is a mosquito‐transmitted alphavirus, and its infection can cause long‐term debilitating arthritis in humans. Currently, there are no licensed vaccines or therapeutics for human use to combat CHIKV infections. In this study, we explored the feasibility of using an anti‐ CHIKV monoclonal antibody ( mA b) produced in wild‐type ( WT ) and glycoengineered (∆ XFT ) Nicotiana benthamiana plants in treating CHIKV infection in a mouse model. CHIKV mA b was efficiently expressed and assembled in plant leaves and enriched to homogeneity by a simple purification scheme. While mA b produced in ∆ XFT carried a single N‐glycan species at the Fc domain, namely GnGn structures, WT produced mA b exhibited a mixture of N‐glycans including the typical plant GnGn XF 3 glycans, accompanied by incompletely processed and oligomannosidic structures. Both WT and ∆ XFT plant‐produced mA bs demonstrated potent in vitro neutralization activity against CHIKV . Notably, both mA b glycoforms showed in vivo efficacy in a mouse model, with a slight increased efficacy by the ∆ XFT ‐produced mA bs. This is the first report of the efficacy of plant‐produced mA bs against CHIKV , which demonstrates the ability of using plants as an effective platform for production of functionally active CHIKV mA bs and implies optimization of in vivo activity by controlling Fc glycosylation.