Liaoyuan Zhang,Xiaoman Yang,Hongyan Shi,Jiyu Zhang,Tingshuai Feng,Dakai Liu,Xin Zhang,Jianfei Chen,Da Shi,Li Feng

Int J Biol Macromol.2024 Aug 23;278(Pt 4):135049.doi: 10.1016/j.ijbiomac.2024.135049. Online ahead of print.

Abstract

Swine acute diarrhea syndrome coronavirus (SADS-CoV) is an emerging alpha-coronavirus that causes diarrhea in piglets and results in serious economic losses. During SADS-CoV infection, the spike protein (S) serves as a crucial structural component of the virion, interacting with receptors and eliciting the production of neutralizing antibodies. Due to the potential risk of zoonotic transmission of SADS-CoV, the identification and screening of epitopes on the S glycoproteins will be crucial for development of sensitive and specific diagnostic tools. In this study, we immunized BALB/c mice with recombinant SADS-CoV S trimer protein and generated two S1-specific monoclonal antibodies (mAbs): 8D6 and 6E9, which recognized different linear B-cell epitopes. The minimal fragment recognized by mAb 8D6 was mapped to 311NPDQRD316, the minimal fragment recognized by mAb 6E9 was mapped to 492ARFVDRL498. Homology analysis of the regions corresponding to 13 typical strains of different SADS-CoV subtypes showed high conservation of these two epitopes. These findings contribute to a deeper understanding of the structure of the SADS-CoV S protein, which is valuable for vaccine design and holds potential for developing diagnostic methods to detect SADS-CoV.

Keywords: Monoclonal antibody; SADS-CoV; Spike protein.