猪-人-鼠嵌合体动物模型的建立及介导人T细胞对猪异种抗原的耐受

Human T-cells developed in a triple chimera animal model and tolerant to porcine xenoantigens

目的:通过共移植人胎胸腺、胎肝组织及猪骨髓细胞于SCID鼠体内,建立猪-人-鼠嵌合体模型,介导人T细胞对猪异种抗原的免疫耐受。方法:实验鼠分成3组:A组为猪骨髓细胞移植组,B组为人胎胸腺、肝脏组织移植组,C组为猪骨髓细胞+人胎胸腺+肝脏组织移植组;在移植后每3周,用流式细胞仪测定猪和人嵌合体的水平,直至20周;通过混和淋巴细胞反应确定人T细胞的功能及对猪异种抗原的耐受情况。结果:猪嵌合体在所有实验鼠(包括共移植人组织的实验鼠)中持续时间均超过20周;在移植人胎组织20周时,T细胞的数量为0.7×106/L,在外周血细胞中所占的百分比为0.14%±0.01%;人嵌合体在所有实验鼠(包括共移植猪骨髓细胞的实验鼠)中持续时间亦超过20周。结论:通过共移植人胎胸腺、胎肝组织及猪造血干细胞于SCID鼠体内,可以建立猪-人-鼠嵌合体模型,并能诱导人T细胞对猪异种抗原的免疫耐受。

AIM： To determine the characteristics （including stability） of a triple chimera animal model generated by implantation of human fetal thymus/liver （Thy/Liv） fragments, fetal liver hematopoietic cells, and porcine bone marrow cells （BMCs） in NOD/SCID mice. METHODS ： NOD/SCID mice were treated with 3 Gy of whole - body irradiation （WBI） and divided into three groups. Group A was given intravenous porcine BMCs. Group B was given an implant of human fetal Thy/Liv fragments （ 1 - 2 mm^3 ） under the right kidney capsule and additionally an intravenous injection of human fetal liver mononuclear cells （MNCs） purified from the fetal livers. The treatment of group C was the combination of both group A and B. Three weeks after Thy/Liv transplantation and every three weeks thereafter, peripheral blood was drawn to determine the level of porcine and human chimerism using muhicolor flow cytometric （FCM） analysis. The proliferation of the T cells was tested in a standard mixed lymphocyte reaction （MLR）. RESULTS ： Porcine chimerism persisted （〉20 weeks） in all mice that received porcine BMCs, including mice that underwent human Thy/Liv implantation later. Human chimerism persisted 〉 20 weeks in all mice that received Thy/Liv implants, regardless of whether they received porcine BMCs transplants. CONCLUSION ： Human immune system is reconstituted by co - transplantation of human fetal Thy/Liv and human fetal liver MNCs in NOD/SCID mice with porcine hematopoietic chimerism. The human T cells are immunocompetent and tolerant to donor porcine BMCs.