Oral immune efficacy of an Escherichia coli mutant strain against Edema disease in swine.

To investigate the protection efficacy of Escherichia coli SLT-Ⅱe gene mutant strain against Edema disease in swine,BALB/c mice were immunized orally with E.coli SLT-Ⅱe gene mutant strain and the immune protection rate in Kunming mice were examined.IgG level in the serum,sIgA level in fecal material and intestine mucus of the immunized mice were detected by ELISA,and the T lymphocyte proliferative response was also evaluated.The results showed that the E.coli mutant strain could induce humoral and mucosal immunity and provoked proliferative response of the T lymphocyte.It provided 75 %(15/20) protection to the mice after challenged intraperitoneally with Shiga-like toxin Ⅱvariant.These results supported the E.coli mutant as a potential oral vaccine candidate against the Edema disease in swine.