Behar S M, Porcelli S A
Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Smith Building Room 518, One Jimmy Fund Way, Boston, MA 02115, USA.
Curr Top Microbiol Immunol. 2007;314:215-50. doi: 10.1007/978-3-540-69511-0_9.
CD1 has been clearly shown to function as a microbial recognition system for activation of T cell responses, but its importance for mammalian protective responses against infections is still uncertain. The function of the group 1 CD1 isoforms, including human CD1a, CDlb, and CDLc, seems closely linked to adaptive immunity. These CD1 molecules control the responses of T cells that are highly specific for particular lipid antigens, the best known of which are abundantly expressed by pathogenic mycobacteria such as Mycobacterium tuberculosis and Mycobacterium leprae. Studies done mainly on human circulating T cells ex vivo support a significant role for group I CD1-restricted T cells in protective immunity to mycobacteria and potentially other pathogens, although supportive data from animal models is currently limited. In contrast, group 2 CD1 molecules, which include human CD1d and its orthologs, have been predominantly associated with the activation of CD1d-restricted NKT cells, which appear to be more appropriately viewed as a facet of the innate immune system. Whereas the recognition of certain self-lipid ligands by CD d-restricted NKT cells is well accepted, the importance of these T cells in mediating adaptive immune recognition of specific microbial lipid antigens remains controversial. Despite continuing uncertainty about the role of CD 1d-restricted NKT cells in natural infections, studies in mouse models demonstrate the potential of these T cells to exert various effects on a wide spectrum of infectious diseases, most likely by serving as a bridge between innate and adaptive immune responses.
CD1已被明确证明可作为激活T细胞反应的微生物识别系统，但其在哺乳动物抗感染保护性反应中的重要性仍不确定。第1组CD1亚型的功能，包括人类CD1a、CD1b和CD1c，似乎与适应性免疫密切相关。这些CD1分子控制着对特定脂质抗原具有高度特异性的T细胞反应，其中最著名的是由致病性分枝杆菌如结核分枝杆菌和麻风分枝杆菌大量表达的脂质抗原。主要在体外对人类循环T细胞进行的研究支持第1组CD1限制性T细胞在针对分枝杆菌以及潜在其他病原体的保护性免疫中发挥重要作用，尽管目前来自动物模型的支持性数据有限。相比之下，第2组CD1分子，包括人类CD1d及其直系同源物，主要与CD1d限制性NKT细胞的激活相关，这些细胞似乎更适合被视为先天免疫系统的一个方面。虽然CD1d限制性NKT细胞对某些自身脂质配体的识别已被广泛接受，但这些T细胞在介导对特定微生物脂质抗原的适应性免疫识别中的重要性仍存在争议。尽管关于CD1d限制性NKT细胞在自然感染中的作用仍存在不确定性，但在小鼠模型中的研究表明，这些T细胞有可能对广泛的传染病产生各种影响，最有可能的方式是作为先天免疫和适应性免疫反应之间的桥梁。
