The Genetic Variation of Porcine Reproductive and Respiratory Syndrome Virus Replicase Protein nsp2 Modulates Viral Virulence and Persistence
Can Kong, Dan Li, Yanxin Hu, Peng Gao, Yongning Zhang, Lei Zhou, Xinna Ge, Xin Guo, Jun Han, Hanchun Yang
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) has been a major threat to the world swine industry. In the field, rapid genetic variations (e.g., deletion, mutation, recombination, etc.) within the nsp2 region present an intriguing conundrum to PRRSV biology and pathogenesis. By making chimeric mutants, here, we show that the Chinese highly pathogenic PRRSV (HP-PRRSV) nsp2 is a virulence factor and a much stronger inducer of host immune responses (e.g., inflammation) than its counterpart, currently epidemic, NADC30-like strains. Differences in the ability to modulate host immunity provide insight into the mechanisms of why NADC30-like strains and their derivatives are rising to be the dominant viruses, whereas the Chinese HP-PRRSV strains gradually give away center stage in the field. Our results have important implications in understanding PRRSV evolution, interlineage recombination, and persistence.