PRRSV GP4 subunit vaccine combined with adenovirus heterologous prime-boost immunization strategy induced a significant immune response in mice.

The porcine reproductive and respiratory syndrome virus (PRRSV) continues to cause widespread infections in the pig industry worldwide. Currently, multiple PRRSV vaccine candidates are in preclinical or clinical trials, and each has different advantages and limitations. Glycoprotein 4 (GP4) is rich in epitopes, which can induce the body to produce neutralizing antibodies, plays a vital role in causing the host immune response, and is a key target for PRRSV vaccine development. In this study, we developed a novel candidate vaccine immunization strategy combining a subunit vaccine with an adenovirus vector vaccine through prokaryotic and eukaryotic systems expressing GP4.