A multicomponent Fc-fused subunit vaccine induces cross-protective immunity against porcine reproductive and respiratory syndrome virus QYYZ-like and NADC30-like strains.

Porcine reproductive and respiratory syndrome (PRRS) causes substantial economic burdens on the global swine industry each year. The emergence of multiple novel recombinant porcine reproductive and respiratory syndrome virus (PRRSV) strains has limited the efficacy of current commercial vaccines, highlighting the urgent need for cross-protective PRRSV vaccines. In this study, GP4Fc, GP5Fc, and MFc fusion proteins were successfully expressed in the Chinese hamster ovary (CHO) cell expression system. The subunit vaccine based on these fusion proteins elicited PRRSV-specific humoral and cellular immune responses in piglets. Challenge experiments demonstrated that this subunit vaccine conferred significant protection against the QYYZ-like strain GX-2428 and the NADC30-like strain GX-3264, reducing viral loads and mitigating lung lesions. Collectively, these findings indicate that PRRSV structural protein-based subunit vaccines fused with Fc fragments represent a promising strategy for the effective control of PRRSV infection.