Vaccine strain of O/ME-SA/Ind-2001e of foot-and-mouth disease virus provides high immunogenicity and broad antigenic coverage

Abstract

Foot-and-mouth disease (FMD) is an economically devastating animal disease. There are seven serotypes, A, O, C, Asia 1, Southern African Territories 1, 2, and 3 (SAT1, SAT2, and SAT3), among which serotype O shows the greatest distribution worldwide. Specifically, the O/ME-SA/Ind-2001 lineage, which was reported in India in 2001, has since emerged worldwide, with the O/ME-SA/Ind-2001d and O/ME-SA/Ind-2001e sublineages recently emerging in North Africa, Middle East Asia, Southeast Asia, and East Asia. The antigenic relationship (r1) value for the O1 Manisa and O/Mya-98 lineage inactivated vaccine against various O/ME-SA/Ind-2001 lineages of FMDV isolates, were matching (r1 > 0.3) or non-matching (r1 < 0.3), indicating that the vaccine based on the O/ME-SA/Ind-2001 lineage FMDV, is valuable. In this study, we developed a new vaccine strain, O/SKR/Boeun/2017 isolate, belonging to the O/ME-SA/Ind-2001e sublineage as an outbreak of this sublineage occurred in 2017 in the Boeun county of the Republic of Korea (O/SKR/Boeun/2017). This experimental vaccine exhibited high immunogenicity in pigs and cattle and was antigenically matched with representative FMDV lineages (ME-SA, O/ME-SA/PanAsia, O/SEA/Mya-98, and O/Cathay) in Asia, as demonstrated by two-dimensional virus neutralization tests (2D-VNT). In addition, a 100% survival rate in C56BL/6 mice vaccinated with 1/15 of a pig dose was observed following challenge with FMDV O/VIT/2013 (O/ME-SA/PanAsia) at 10 days post-vaccination. Further, we analyzed the major antigenic sites of the O/SKR/Boeun/2017 vaccine strain as well as other viruses, by 2D-VNT. These results suggest that the O/ME-SA/Ind-2001e sublineage is a promising vaccine strain candidate in Asia, and other countries, for protection against the emerging FMDV.