FIG. 1.

DTH response. BALB/c mice (three per group) were immunized three times with DNA (pc, vector pcDNA3, pM, MOMP gene in vector pcDNA3) intramuscularly at 2-week intervals or immunized once with live MoPn EBs (EB; 1,000 IFU) intranasally. Fourteen days after the third immunization, the DNA-immunized groups were boosted with MOMP ISCOM protein (pc/IS, pcDNA primed and MOMP ISCOM boosted; pM/IS, MOMP DNA primed and MOMP ISCOM boosted). N, naive mice as a control. All mice were injected with 25 μl of 2 × 10⁴ IFU of UV-killed MoPn EBs in SPG into one hind footpad 14 days after boosting; 25 μl of SPG buffer was injected into the other hind footpad as a control. Footpad swelling was measured at 48 h following the injection. The difference in thickness between the two footpads was used as a measure of DTH. The data are means ± SEM. ∗∗, P < 0.01 compared with N, IS, and pc/IS.