N-linked glycosylation of GETV envelope proteins affect viral infection and pathogenicity

Getah virus (GETV) is an emerging mosquito-borne pathogen with a broad host range, posing a significant threat to livestock and public health. Although putative N-linked glycosylation sites on its envelope proteins have been reported, their precise functional roles remain uncharacterized. In this study, tunicamycin inhibition assays demonstrated that GETV replication depends on the host glycosylation machinery. Enzymatic dissection revealed that the envelope proteins E1 and E2 carry complex-type N-linked glycans, which are critical for infectivity. By constructing envelope protein N-linked glycosylation site mutants, it was revealed that the E1-N141 site influences viral entry, whereas the E2-N262 site was critical for both viral adsorption and invasion. Mutations at all envelope protein N-linked glycosylation sites impaired the infectivity of progeny virions, resulting in delayed replication kinetics and significantly reduced viral titers. In a suckling mouse model, all mutants showed attenuated pathogenicity, with the E2-N200 mutation conferring the most substantial reduction in virulence. Notably, despite reduced virulence, some mutants (E1-N141A and E2-N200A/N262A) elicited neutralizing antibody responses stronger than those induced by wild-type virus and provided complete protection against subsequent challenge with wild-type GETV. These findings highlight the critical role of envelope protein glycosylation in GETV infectivity and pathogenesis, providing a molecular basis for rational vaccine design.