Surprisingly, the challenge study revealed a different scenario, whereby the maximum protection percentage (87.5%) observed in the FMDV-CS-NP I/M group was even greater than that in the conventional vaccine group (77.7%) and the FMDV-CS-NP I/N group, indicating a role of mucosal antibodies in neutralizing viruses at the primary sites of replication, thereby impeding the systemic establishment of infection in animals. The gene discussed is NPTX1; the disease is infection.