the average antibody titers(agglutination titer)of the whole-cell vaccine immunization, injection immunization and microencapsulated vaccine oral immunization were respectively 1:19,1:190,1:62;
the lamina propria cd4+ t cells and the mast cells in jejunum were also increased(p > 0.05 and p01, respectively) at 3 weeks after oral immunization compared with control group.