In some cases, the blots were reprobed using rabbit serum against rOmpL1 or rLipL41(dilution
selleck compound 1:300) after stripping off the first antibody by incubation in the stripping buffer (65 mM Tris-HCl pH 6.7, 100 mM beta-mercaptoethanol, 2% SDS). Wild type M13KE particles were used as controls. The reactivity of each epitope with antiserum mixture from IgM- and IgG-positive leptospirosis patients who were infected by different leptospiral serovars was also evaluated by Western blot [21]. IgM- and IgG-positive serum samples from leptospire-infected humans were pooled together and used as primary antibody (1:50 dilution). The antisera were incubated with the PVDF membrane at 37°C for about 1.5 h. After a washing step, goat anti-human IgG-HRP (1:5000 dilution) was used as secondary antibody. Wild type M13KE particles were also used as controls. Mice and immunization 100 μg rOmpL1 or rLipL41 protein pre-mixed with complete Freund’s adjuvant (Sigma) was used
to inject subcutaneously in the four limbs of 6-8 week old female BALB/c (H-2d) mice,. Same dose of proteins for boosting immune responses were given with incomplete Freund’s adjuvant (Sigma) two weeks later. After 10 days, the mice were used for further experiments. Control mice were administered with PBS by the same procedures. Detection of T cell response For the analysis of specific AZD1152 manufacturer CD4+ T cell proliferation, spleens were aseptically removed and mechanically homogenized with a 3-ml syringe plunger, and then splenocytes were isolated by lymphocyte separation medium (mouse) according to the manufacturer’s instruction. Complete RPMI 1640 media (RPMI-1640, 10% fetal bovine serum, 2 mM glutamine, 50 U of penicillin/ml, 50 μg of streptomycin/ml, 50 μM 2-mercaptoethanol, and 25 mM HEPES) was used to cultivate the cells. 100 μl isolated T cells (5 × 104 cells per well) and mitomycin-inactivated allogeneic splenocytes (105 cells per well) were seeded into enough 96-well flat bottom culture plates and restimulated in vitro with different epitopes at a concentration
of 5 × 1014 recombinant phage particles per cell. 5 μg/ml mitogen concanavalin A (ConA) was used as control. Cells were incubated at 37°C with 5% CO2 for 72 h. The cell proliferation was measured using Cell Counting Kit (CCK)-8 according to the manufacturer’s instruction. Briefly, 20 μl CCK solution was added to the culture medium and incubated for additional 3 h. The absorbance was determined at 450 nm with a 630 nm reference wavelength using ELISA Reader (Bio-Rad). Unstimulated cells were used as negative control and ConA-stimulated cells were used as positive control. Tests were find more repeated at least three times independently. Phages expressing each epitope were mixed together to evaluate if there is synergistic effect of these epitopes in the stimulation of the splenocytes isolated from the immunized mice.