gondii tachyzoite polyclonal antibody (37°C for 2 h) in a humidified box. After washing the plates three times with PBST, fluorescein isothiocyanate (FITC)-labelled goat anti-mouse IgG (1 : 2000; Boster, Wuhan, China) was applied to all the cells and incubated at 37°C selleck for 1 h. After washing the cells three more times with PBST, the fluorescence was observed under a fluorescence microscope (Olympus BX-51, Tokyo, Japan). Six- to eight-week-old female BALB/c mice were randomly divided

into three groups (13 mice per group) and immunized by intramuscular injection. pVAX1-TgCyP (100 μg/each in PBS) was used to immunize the mice for the experimental group (a 0·05 mL syringe and a 20G needle were used for the injection); the empty pVAX1 vector (100 μg/each in PBS) and PBS (100 μL/each) were used as negative controls. All groups were vaccinated in the same manner on days 0, 14 and 28. Blood was collected from each group via the venous plexus of the tail before each immunization and stored at −20°C mTOR inhibitor for enzyme-linked immunosorbent assay (ELISA) analysis. An indirect ELISA test was applied to evaluate specific antibodies according

to the procedure described previously [12]. The 96-well microtiter plates were coated overnight at 4°C with crude T. gondii tachyzoite antigens (10 mg/mL). On the second day, the plates were blocked with 5% bovine serum albumin (BSA) in PBS at room temperature for 2 h. Then, the plates were washed three times with PBST, and incubated with mouse sera (1 : 3200 in 1% BSA-PBS) at 37°C for 1·5 h. After washing three times with PBST, the plates were incubated with an HRP-labelled goat anti-mouse IgG antibody (1 : 2000; Boster) at 37°C for 1 h. After washing three times with PBST, a substrate solution containing 15 μL H2O2, 10 ml citrate-phosphae

and 4 mg O-phenylenediamine (OPD) was applied (100 μL/well). The reaction was stopped with 2 m H2SO4, and the optical density values were read at A490. Spleens were removed from five mice per group 14 days after the final vaccination. A splenocyte BCKDHB suspension was obtained by the gentle squeezing of whole spleens in Hank’s balanced salt solution (HBSS, Sigma, St. Louis, MO, USA) and filtration through nylon mesh. The erythrocytes in the spleen cell suspension were removed by lysis and centrifugation. The pellet was washed three times with PBS and resuspended with complete RPMI-1640 medium supplemented with 10% FCS. The cells were cultured in 96-well Costar plates at a density of 103 cells/well. The splenocytes were stimulated with TLA (10 μg/mL), concanavalin A (Con A; 5 μg/mL; Sigma; positive control) or medium alone (negative control). After incubation with Alamar blue (10 μL/well) for 12 h, the plates were read at 570 nm with an ELISA reader. Lymphocyte proliferative responses were represented by a stimulation index (SI), which is the OD570 ration between stimulated cells and nonstimulated cells.