Thibodeau J, Labrecque N, Denis F, Huber B T, Sékaly R P
Laboratoire d'Immunologie, Institut de Recherches Cliniques de Montréal, Québec, Canada.
J Exp Med. 1994 Mar 1;179(3):1029-34. doi: 10.1084/jem.179.3.1029.
Bacterial and retroviral superantigens (SAGs) interact with major histocompatibility complex (MHC) class II molecules and stimulate T cells upon binding to the V beta portion of the T cell receptor. Whereas both types of molecules exert similar effects on T cells, they have very different primary structures. Amino acids critical for the binding of bacterial toxins to class II molecules have been identified but little is known of the molecular interactions between class II and retroviral SAGs. To determine whether both types of superantigens interact with the same regions of MHC class II molecules, we have generated mutant HLA-DR molecules which have lost the capacity to bind three bacterial toxins (Staphylococcus aureus enterotoxin A [SEA], S. aureus enterotoxin B [SEB], and toxic shock syndrome toxin 1 [TSST-1]). Cells expressing these mutated class II molecules efficiently presented two retroviral SAGs (Mtv-9 and Mtv-7) to T cells while they were unable to present the bacterial SAGs. These results demonstrate that the binding sites for both types of SAGs can be dissociated.
细菌超抗原和逆转录病毒超抗原（SAGs）与主要组织相容性复合体（MHC）II类分子相互作用，并在与T细胞受体的Vβ部分结合时刺激T细胞。虽然这两种分子对T细胞产生相似的作用，但它们具有非常不同的一级结构。已经确定了细菌毒素与II类分子结合至关重要的氨基酸，但对于II类分子与逆转录病毒SAGs之间的分子相互作用却知之甚少。为了确定这两种超抗原是否与MHC II类分子的相同区域相互作用，我们构建了突变的HLA-DR分子，这些分子失去了结合三种细菌毒素（金黄色葡萄球菌肠毒素A [SEA]、金黄色葡萄球菌肠毒素B [SEB]和中毒性休克综合征毒素1 [TSST-1]）的能力。表达这些突变II类分子的细胞能够有效地将两种逆转录病毒SAGs（Mtv-9和Mtv-7）呈递给T细胞，而它们无法呈递细菌SAGs。这些结果表明，这两种类型的SAGs的结合位点可以分离。
