title: The soluble tachyzoite antigen of Toxoplasma gondii has a protective effect on mouse allografts.
abstract: BACKGROUND
  Infection with some types of parasites can significantly prolong allograft survival in mice. It is unknown whether the soluble tachyzoite antigen (STAg) from Toxoplasma gondii has the same effect and by what mechanism it acts.
  
  
  METHODS
  A mouse model of cardiac and skin allograft transplantation was established between BALB/c (H-2(d)) and C57BL/6(H-2(b)) mice. T gondii STAg was prepared, and 5 μg was administered subcutaneously to recipient mice 4 days before transplantation. The graft status was checked daily, and histologic and immunohistochemical assays were used to evaluate rejection. The serum cytokine levels from the recipient mice were analyzed by Luminex.
  
  
  RESULTS
  The administration of 5 μg STAg 4 days before transplantation significantly prolonged the survival time of the heart and skin allografts to 85.17 ± 14.06 and 24.17 ± 2.32 days, respectively. Immunohistochemical staining showed that the CD4(+) and CD8(+) T lymphocytes were markedly reduced in the allografts at day 7 posttransplantation. Notably, interleukin (IL)-12, IL-2, and IL-17 levels were significantly reduced in the serum of mice treated with STAg compared with untreated mice 7 days after transplantation. In contrast, the levels of the antiinflammatory cytokine IL-10 were elevated.
  
  
  CONCLUSIONS
  A single administration of STAg before transplantation can significantly prolong the allograft survival time, which is accompanied by impaired lymphocyte infiltration and a reduced Th1 response.
authors.affiliation: Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Key Laboratory of Ministry of Health, Key Laboratory of Ministry of Education, Wuhan, China.
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.forename: Z
authors.initials: Z
authors.lastname: Fang
authors.forename: X
authors.initials: X
authors.lastname: Huang
authors.forename: X
authors.initials: X
authors.lastname: Luo
authors.forename: Z
authors.initials: Z
authors.lastname: Fang
authors.forename: N
authors.initials: N
authors.lastname: Gong
authors.forename: C
authors.initials: C
authors.lastname: Ming
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000008:administration & dosage / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D006084:Graft Rejection / Q000097:blood / Q000276:immunology / Q000517:prevention & control*; D006085:Graft Survival; D016027:Heart Transplantation / Q000009:adverse effects / Q000276:immunology*; D007150:Immunohistochemistry; D007279:Injections, Subcutaneous; D007378:Interleukins / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism; D016038:Skin Transplantation / Q000009:adverse effects / Q000276:immunology*; D013997:Time Factors; D014122:Toxoplasma / Q000276:immunology*
chemical_list: D000953:Antigens, Protozoan; D007378:Interleukins; D016328:NF-kappa B; C094052:soluble tachyzoite antigen, Toxoplasma gondii