Resetkova E, Kawai K, Enomoto T, Arreaza G, Togun R, Foy T M, Noelle R J, Volpé R
Endocrinology Research Laboratory, Wellesley Hospital, University of Toronto, Ontario, Canada.
Thyroid. 1996 Aug;6(4):267-73. doi: 10.1089/thy.1996.6.267.
Experimental evidence suggests that interference with gp39-CD40 interactions may have therapeutic potential in prevention of certain autoimmune disorders (i.e., collagen-induced rheumatoid arthritis). The binding between CD40 expressed on mature B cells and CD40 ligand (CD40L, gp39) transiently expressed on activated T helper cells (Th) further stabilizes the interactions (between Th and B cells) and co-ordinates the responses of the interacting cells during antigen presentation, and is essential for thymus-dependent humoral immunity. Graves' disease is the most common form of hyperthyroidism, in which hyperactivity of the thyroid gland is due to an autoantibody directed against the thyrotropin receptor (TSHR). The main objective of our study was to determine the role of interactions between gp39 and CD40 in "an established" human Graves' disease (GD). Severe combined immunodeficient (SCID) mouse served as a vehicle for human Graves' thyroid tissue. This experimental setting allows us to study, observe, and immunomodulate human autoimmune tissue in so called in vivo condition. We studied the effects of ip administration of anti-gp39 mAb on humoral response, thyroid function tests, expression of adhesion molecules, and HLA-DR on human thyrocytes and histopathological changes from human GD thyroid tissue xenografts. GD thyroid tissue from 4 patients was xenografted into 20 SCID mice (0.8 g/mouse). Human immunoglobulin G (IgG) levels became detectable in SCID mice 1 week after xenograftment. Ten SCID mice were sequentially administered anti-gp39 mAb (250 micrograms/mouse/ dose) ip every 4 days until the end of the experiment. Ten control animals were injected with vehicle (PBS) in similar fashion. Blood samples were taken every 2 weeks from the tail veins for measurement of the humoral response [human IgG, thyroid-stimulating antibody (TSAb), antithyroperoxidase (anti-TPO), and antithyroglobulin (anti-Tg), Abs], and thyroid function tests. After 8 weeks, animals were sacrificed and thyroid tissue was examined histologically. The humoral response from the intrathyroidal lymphocytes was measured and the tissue morphology of GD was preserved during the 8-week period in phosphate-buffered saline (PBS)-treated SCID mice xenografted with GD xenografts. However, administration of anti-gp39 mAb completely blocked or significantly decreased the humoral response in all treated animals. On the other hand, no significant histological changes were associated with the administration of anti-gp39 mAb. The degree of lymphocytic infiltration in thyroid tissue xenografts was comparable in both groups. Serum thyroxine values were normal in both groups. In spite of a profound immunosuppressive effect on the humoral response by directly blocking CD40-gp39 interactions in vivo, this did not result in complete deletion of the responding Th in the thyroid specimens.
实验证据表明，干扰gp39与CD40的相互作用可能在预防某些自身免疫性疾病（如胶原诱导的类风湿性关节炎）方面具有治疗潜力。成熟B细胞上表达的CD40与活化的辅助性T细胞（Th）上瞬时表达的CD40配体（CD40L，gp39）之间的结合进一步稳定了（Th和B细胞之间的）相互作用，并在抗原呈递过程中协调相互作用细胞的反应，对于胸腺依赖性体液免疫至关重要。格雷夫斯病是甲状腺功能亢进最常见的形式，其中甲状腺功能亢进是由于针对促甲状腺素受体（TSHR）的自身抗体引起的。我们研究的主要目的是确定gp39与CD40之间的相互作用在“已确诊的”人类格雷夫斯病（GD）中的作用。严重联合免疫缺陷（SCID）小鼠作为人类格雷夫斯甲状腺组织的载体。这种实验设置使我们能够在所谓的体内条件下研究、观察和免疫调节人类自身免疫组织。我们研究了腹腔注射抗gp39单克隆抗体对体液反应、甲状腺功能测试、黏附分子表达以及人甲状腺细胞上HLA-DR的影响，以及人类GD甲状腺组织异种移植的组织病理学变化。将4例患者的GD甲状腺组织异种移植到20只SCID小鼠体内（每只小鼠0.8 g）。异种移植后1周，在SCID小鼠体内可检测到人类免疫球蛋白G（IgG）水平。10只SCID小鼠每4天腹腔注射抗gp39单克隆抗体（每只小鼠/剂量250微克），直至实验结束。10只对照动物以类似方式注射载体（PBS）。每2周从尾静脉采集血样，用于测量体液反应[人类IgG、促甲状腺素刺激抗体（TSAb）、抗甲状腺过氧化物酶（抗TPO）和抗甲状腺球蛋白（抗Tg）抗体]以及甲状腺功能测试。8周后，处死动物并对甲状腺组织进行组织学检查。测量甲状腺内淋巴细胞的体液反应，在用GD异种移植的磷酸盐缓冲盐水（PBS）处理的SCID小鼠中，GD的组织形态在8周内得以保留。然而，抗gp39单克隆抗体的给药完全阻断或显著降低了所有处理动物的体液反应。另一方面，抗gp39单克隆抗体的给药未引起明显的组织学变化。两组甲状腺组织异种移植中的淋巴细胞浸润程度相当。两组血清甲状腺素值均正常。尽管通过在体内直接阻断CD40-gp39相互作用对体液反应有显著的免疫抑制作用，但这并未导致甲状腺标本中反应性Th完全缺失。
