de Lima Moreira Marcela, Souter Michael N T, Chen Zhenjun, Loh Liyen, McCluskey James, Pellicci Daniel G, Eckle Sidonia B G
Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Vic., Australia.
Australian Research Council Centre of Excellence in Advanced Molecular Imaging, University of Melbourne, Parkville, Vic., Australia.
Allergy. 2020 Oct;75(10):2477-2490. doi: 10.1111/all.14279. Epub 2020 Apr 13.
Conventional T cells recognise protein-derived antigens in the context of major histocompatibility complex (MHC) class Ia and class II molecules and provide anti-microbial and anti-tumour immunity. Conventional T cells have also been implicated in type IV (also termed delayed-type or T cell-mediated) hypersensitivity reactions in response to protein-derived allergen antigens. In addition to conventional T cells, subsets of unconventional T cells exist, which recognise non-protein antigens in the context of monomorphic MHC class I-like molecules. These include T cells that are restricted to the cluster of differentiation 1 (CD1) family members, known as CD1-restricted T cells, and mucosal-associated invariant T cells (MAIT cells) that are restricted to the MHC-related protein 1 (MR1). Compared with conventional T cells, much less is known about the immune functions of unconventional T cells and their role in hypersensitivities. Here, we review allergen antigen presentation by MHC-I-like molecules, their recognition by unconventional T cells, and the potential role of unconventional T cells in hypersensitivities. We also speculate on possible scenarios of allergen antigen presentation by MHC-I-like molecules to unconventional T cells, the hallmarks of such responses, and the expected frequencies of hypersensitivities within the human population.
传统T细胞在主要组织相容性复合体（MHC）I类和II类分子的背景下识别蛋白质衍生的抗原，并提供抗微生物和抗肿瘤免疫力。传统T细胞也参与了针对蛋白质衍生的变应原抗原的IV型（也称为迟发型或T细胞介导型）超敏反应。除了传统T细胞外，还存在非常规T细胞亚群，它们在单态性MHC I类样分子的背景下识别非蛋白质抗原。这些包括限于分化簇1（CD1）家族成员的T细胞，称为CD1限制型T细胞，以及限于MHC相关蛋白1（MR1）的黏膜相关恒定T细胞（MAIT细胞）。与传统T细胞相比，人们对非常规T细胞的免疫功能及其在超敏反应中的作用了解较少。在这里，我们综述了MHC-I类样分子的变应原抗原呈递、非常规T细胞对其的识别以及非常规T细胞在超敏反应中的潜在作用。我们还推测了MHC-I类样分子向非常规T细胞呈递变应原抗原的可能情况、此类反应的特征以及人群中超敏反应的预期发生率。
