[Changes in splenocyte proliferation, subsets and cytokine production in mice immunized with recombinant vaccine Bifidobacterium bifidum (pGEX-Sj32) of Schistosoma japonicum].
OBJECTIVE
To observe the dynamic changes of immune responses of splenocytes in mice immunized with recombinant vaccine Bifidobacterium bifidum (pGEX-Sj32) of Schistosoma japonicum and investigate the immunological mechanism of the vaccine.


METHODS
Eighty-eight BALB/c mice were randomized for immunization with 10⁶ CFU recombinant vaccine orally or with 10⁵ CFU recombinant vaccine intranasally. Four mice were selected from each group every two weeks to test the responses of the splenocytes to stimulations with SjAWA or ConA. MTT assay and flow cytometry were used to assess splenocyte proliferation and the distribution of CD4⁺ and CD8⁺ T cells, respectively; the levels of interleukin-10 (IL-10), IL-12 and tumor necrosis factor-α (TNF-α) in the cell culture supernatant were detected by ELISA.


RESULTS
Regardless of the stimulations, the splencytes showed significantly enhanced proliferation in weeks 2-16 in oral administration group and in weeks 2-18 in intranasal group (P<0.01). CD4⁺ subsets in both two groups increased obviously in weeks 2-12 (P<0.01) but CD8⁺ subsets remained stable. In oral administration group, the levels of TNF-α, IL-10 and IL-12 increased in weeks 2-14, 2-18 and 2-14, and peaked at week 8, 10 and 6, respectively; in intranasal group, the cytokines increased in weeks 2-14, 2-18 and 2-18, and peaked at week 8, 10 and 8, respectively.


CONCLUSIONS
The recombinant vaccine rBb (pGEX-Sj32) can induce effective immune responses in mice.
Institute of Infectious and Parasitic Disease, First Affi1iated Hospital, Chongqing Medical University, Chongqing 400016, China.E-mail: 286246114@qq.com.
Jianrong
J
Tan
Wengui
W
Li
Ting
T
Qin
D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology*; D001644:Bifidobacterium; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology; D018664:Interleukin-12 / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D012549:Schistosoma japonicum; D012554:Schistosomiasis japonica / Q000517:prevention & control*; D013154:Spleen / Q000166:cytology / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000276:immunology*
D000947:Antigens, Helminth; D014409:Tumor Necrosis Factor-alpha; D014614:Vaccines, Synthetic; D016753:Interleukin-10; D018664:Interleukin-12