Protective effect of a mixed recombinant Bifidobacterium vaccine of Taenia solium in piglets / 中华地方病学杂志

ABSTRACT

Objective To study the protective effect of a mixed recombinant Bifidobacterium (Bb) vaccine of Taenia solium in piglets. Methods Healthy piglets of 40 days old were randomly divided into experimental group and control group, 4 in each group. Experimental group was given 1011 CFU rBb-TSO45W-4B vaccine and rBb-TSOL18 vaccine (in the ratio of 1 1). Control group was given Bb liquid medium (MRS). A total of two times of immunization were conducted, once for every two weeks. At different time points after immunization, the serum was separated from precaval vein blood to detect the level of IgG by enzyme linked immunosorbent assay (ELISA). Piglets were challenged with Taenia solium eggs on the 4th week after the last immunization and killed 3 months after infection. The cysticerci were separated to count and calculate the reduction rate of cysticerci. Blood from precaval vein was collected to separate serum and prepare peripheral blood lymphocytes (PBMC). The levels of IgG,IgG1 and IgG2a in serum sampl es and the levels of interleukin ( IL )-2 , interferon (IFN)-γ, IL-4 and IL-10 in PBMC culture supernatant were determined by ELISA. The level of PBMC proliferation was tested using methyltetrazolium (MTT) assay. Results In experimental group, the level of serum IgG increased from the 2nd to the 8th weeks after immunization, and reached the highest level on the 4th week after immunization (mg/L270 . 64 ± 1 . 94 vs 207.74 ± 2.24, t=42.479, P<0.05). Reduction rate of cysticercus was 80.48%. Compared with control group, the levels of IgG and IgG2a in serum were significantly increased, while the level of IgG1 was significantly decreased (mg/L 364.15 ± 11.52 vs 245.94 ± 8.81, 89.74 ± 1.13 vs 62.61 ± 0.84, 20.52 ± 1.00 vs 34.11 ± 0.65, t=16.303, 38.579, - 22.772, P < 0.05). The levels of IL-2 and IFN-γ in PBMC culture supernatant were significantly increased, while the levels of IL-4 and IL-10 were significantly decreased (ng/L215.24 ± 3.31 vs 174.19 ± 2.14, 28.21 ± 0.27 vs 17.69 ± 0.28, 40.35 ± 0.34 vs 52.57 ± 0.29, 71.34 ± 0.36 vs 94.82 ± 0.45, t =20.839, 53.623,-54.743,- 81.266, P<0.05). The level of PBMC proliferation was significantly increased (0.620 ± 0.051 vs 0.242 ± 0.053, t=10.259, P<0.05). Conclusions It is concluded that the mixed rBb vaccine of Taenia solium might give piglets a certain protection. Th1 type immune response plays an important role in the protection.