The cellular-mediated immune responses. (A) The cytokines. After 2nd boost immunized 1 week, the sera from all experiment groups were collected to detect cytokine by ELISA. (B) spleen lymphocyte proliferation response. The spleen lymphocytes were incubated in 96-well flat-bottomed microtiter plates and stimulated with rMEP for detecting the spleen lymphocyte proliferation response by MTT. The data are shown as mean ± SD of three independent experiments. Statistically significant differences (P < 0.05) are indicated with different small letters.