Hodtsev A S, Choi Y, Spanopoulou E, Posnett D N
Ruttenberg Cancer Center, Mount Sinai School of Medicine, New York 10029, USA.
J Exp Med. 1998 Feb 2;187(3):319-27. doi: 10.1084/jem.187.3.319.
Superantigens are defined as proteins that activate a large number of T cells through interaction with the Vbeta region of the T cell antigen receptor (TCR). Here we demonstrate that the superantigen produced by Mycoplasma arthritidis (MAM), unlike six bacterial superantigens tested, interacts not only with the Vbeta region but also with the CDR3 (third complementarity-determining region) of TCR-beta. Although MAM shares typical features with other superantigens, direct interaction with CDR3-beta is a feature of nominal peptide antigens situated in the antigen groove of major histocompatibility complex (MHC) molecules rather than superantigens. During peptide recognition, Vbeta and Valpha domains of the TCR form contacts with MHC and the complex is stabilized by CDR3-peptide interactions. Similarly, recognition of MAM is Vbeta-dependent and is apparently stabilized by direct contacts with the CDR3-beta region. Thus, MAM represents a new type of ligand for TCR, distinct from both conventional peptide antigens and other known superantigens.
超抗原被定义为通过与T细胞抗原受体（TCR）的Vβ区域相互作用而激活大量T细胞的蛋白质。在此我们证明，关节炎支原体产生的超抗原（MAM）与所测试的六种细菌超抗原不同，它不仅与Vβ区域相互作用，还与TCR-β的CDR3（第三互补决定区）相互作用。尽管MAM与其他超抗原具有共同的典型特征，但与CDR3-β的直接相互作用却是位于主要组织相容性复合体（MHC）分子抗原槽中的名义肽抗原的特征，而非超抗原的特征。在肽识别过程中，TCR的Vβ和Vα结构域与MHC形成接触，并且该复合物通过CDR3-肽相互作用得以稳定。同样，对MAM的识别依赖于Vβ，并且显然通过与CDR3-β区域的直接接触而得以稳定。因此，MAM代表了一种新型的TCR配体，不同于传统的肽抗原和其他已知的超抗原。
