Neutralization of genotype 2 porcine epidemic diarrhea virus strains by a novel monoclonal antibody

Liu, Jianbo; Shi, Hongyan; Chen, Jianfei; Zhang, Xin; Ji, Zhaoyang; Yuan, Jing; Shi, Da; Cao, Liyan; Zhu, Xiangdong; Dong, Hui; Wang, Xiaobo; Zhang, Jialin; Feng, Li

Abstract Porcine epidemic diarrhea virus (PEDV) has two genotypes, G1 and G2. To research the immunogenicity differences of PEDV G1 and G2 genotype strains and obtain a neutralizing monoclonal antibody (mAb), we inoculated specific-pathogen-free BALB/c mice with a newly emerged strain, PEDV-LNCT2. After immunizations, cells from the spleen of the mice were fused with SP2/0 myeloma cells. Following culturing and subcloning, a strain, 1B9, secreting neutralizing antibody, was obtained. The 1B9 mAb neutralized new variant genotype 2 PEDV strains (LNCT2, LNSY, and Hjms), but it did not neutralize a genotype 1 PEDV strain (CV777), in vitro. Results showed that the epitope recognized by the 1B9 mAb lies in the spike protein, and that it is a conformational epitope. These findings confirm that allelic differences in the PEDV S gene between the G1 and G2 genotype strains led to changes in the S protein and, thus, differences in its immunogenicity.