N-terminal Domain of the Spike Protein of Porcine Epidemic Diarrhea Virus as a New Candidate Molecule for a Mucosal Vaccine

Kim, Sae-Hae; Cho, Byeol-Hee; Lee, Kyung-Yeol; Jang, Yong-Suk

In the gut mucosa, M cells have a unique α (1,2)-fucose-containing carbohydrate moiety compared with enterocytes that can be detected using an M cell-specific Ab (NKM 16-2-4) (16) . By contrast, WGA binds to enterocytes but not to M cells. Based on these observations, we assumed that the NTD 231-501 interacts with specific glycan motifs expressed on M cells such as M cell-specific NKM 16-2-4 Ab. To this end, we aimed to determine whether recombinant NTD 231-501 of the PEDV S1 protein binds on the apical area of M cells. Therefore, recombinant NTD 231-501 was incubated with whole-mount PPs to monitor potential specific binding of the protein to the apical area of M cells (Fig. 3B) . Recombinant NTD 231-501 localized to the apical area of M cells, which stained with NKM 16-2-4 but not with WGA. Therefore, we hypothesize that recombinant NTD 231-501 of the PEDV S1 protein functions as a mucosal Ag capable of targeting itself to M cells, which are involved in mucosal Ag uptake.