Head J R, Griffin W S
Proc R Soc Lond B Biol Sci. 1985 May 22;224(1236):375-87. doi: 10.1098/rspb.1985.0039.
The capacity of the mammalian brain to support the physiological function of allografts was assessed in parathyroidectomized Fischer strain rats bearing either isografts or immunogenic DA allografts of parathyroid glands implanted in their cerebral cortices. Established isografts and allografts survived indefinitely in the brain, maintaining normal serum calcium levels, with equal numbers of spontaneous failures (18-21%) in each group. Similarly, both MHC-compatible and incompatible skin allografts survived and were 'functional' at 40-50 days postgrafting as assessed by: continued formation of keratin; the presence of differentiated hair follicles and sebaceous glands; and frequent mitotic figures. No serum alloantibodies were induced by either MHC-incompatible parathyroid glands or skin in this site. However, both types of allografts were promptly rejected or failed to become established in the brains of specifically presensitized hosts. Furthermore, when Fischer hosts with long-established intracerebral DA parathyroid grafts received orthotopic DA skin grafts, their parathyroid grafts were rejected along with first-set rejection of the skin grafts. The tempo of this cellular immune response and the primary alloantibody response that accompanied it indicate that although the intracerebral grafts failed to induce detectable host sensitization or suppression, they remained susceptible to immune effectors. Thus, by using strongly immunogenic, adult tissues, we have established that the rat cerebral cortex is an immunologically privileged site, and the privilege is not dependent on lack of graft immunogenicity or alterations in host responsiveness. Furthermore, Ia+ (possible antigen-presenting) cells were rare in the cortical parenchyma sites used for transplantation though numerous in the choroid plexus of the ventricles and in certain areas of white matter. Therefore, privilege probably reflects deficient graft antigen presentation related to the paucity of Ia+ cells as well as to the brain's poor lymphatic drainage.
在甲状旁腺切除的Fischer品系大鼠中评估了哺乳动物大脑支持同种异体移植生理功能的能力，这些大鼠的大脑皮层植入了同基因移植体或免疫原性的甲状旁腺DA同种异体移植体。已建立的同基因移植体和同种异体移植体在大脑中无限期存活，维持正常的血清钙水平，每组的自发失败数量相同（18 - 21%）。同样，通过以下评估，MHC相容和不相容的皮肤同种异体移植体在移植后40 - 50天存活且“功能正常”：角质持续形成；存在分化的毛囊和皮脂腺；以及频繁的有丝分裂象。在该部位，MHC不相容的甲状旁腺或皮肤均未诱导血清同种抗体。然而，在特异性预致敏宿主的大脑中，这两种类型的同种异体移植体均被迅速排斥或未能建立。此外，当具有长期存在的脑内DA甲状旁腺移植体的Fischer宿主接受原位DA皮肤移植时，它们的甲状旁腺移植体与皮肤移植体的初次排斥反应一起被排斥。这种细胞免疫反应的速度以及伴随的初次同种抗体反应表明，尽管脑内移植体未能诱导可检测到的宿主致敏或抑制，但它们仍然易受免疫效应器的影响。因此，通过使用强免疫原性的成年组织，我们确定大鼠大脑皮层是一个免疫特惠部位，并且这种特惠并不依赖于移植体缺乏免疫原性或宿主反应性的改变。此外，用于移植的皮质实质部位Ia +（可能的抗原呈递）细胞很少，而在脑室脉络丛和某些白质区域则很多。因此，特惠可能反映了与Ia +细胞稀少以及大脑淋巴引流不良相关的移植体抗原呈递不足。
