Grigg M E, McMahon C W, Morkowski S, Rudensky A Y, Pullen A M
Howard Hughes Medical Institute and Department of Immunology, University of Washington School of Medicine, Seattle 98195, USA.
J Virol. 1998 Apr;72(4):2577-88. doi: 10.1128/JVI.72.4.2577-2588.1998.
Presentation of the Mtv-1 superantigen (vSag1) to specific Vbeta-bearing T cells requires association with major histocompatibility complex class II molecules. The intracellular route by which vSag1 trafficks to the cell surface and the site of vSag1-class II complex assembly in antigen-presenting B lymphocytes have not been determined. Here, we show that vSag1 trafficks independently of class II to the plasma membrane by the exocytic secretory pathway. At the surface of B cells, vSag1 associates primarily with mature peptide-bound class II alphabeta dimers, which are stable in sodium dodecyl sulfate. vSag1 is unstable on the cell surface in the absence of class II, and reagents that alter the surface expression of vSag1 and the conformation of class II molecules affect vSag1 stimulation of superantigen reactive T cells.
将Mtv-1超抗原（vSag1）呈递给特定的带有Vβ的T细胞需要与主要组织相容性复合体II类分子结合。vSag1转运至细胞表面的细胞内途径以及抗原呈递B淋巴细胞中vSag1-II类复合体组装的位点尚未确定。在此，我们表明vSag1通过外排分泌途径独立于II类分子转运至质膜。在B细胞表面，vSag1主要与成熟的肽结合II类αβ二聚体结合，这些二聚体在十二烷基硫酸钠中稳定。在没有II类分子的情况下，vSag1在细胞表面不稳定，并且改变vSag1表面表达和II类分子构象的试剂会影响vSag1对超抗原反应性T细胞的刺激。
