Brossard Cédric, Feuillet Vincent, Schmitt Alain, Randriamampita Clotilde, Romao Maryse, Raposo Graça, Trautmann Alain
Département de Biologie Cellulaire, Institut Cochin, INSERM U567, CNRS UMR 8104, Université René Descartes, Paris, France.
Eur J Immunol. 2005 Jun;35(6):1741-53. doi: 10.1002/eji.200425857.
The structure of immunological synapses formed between murine naive T cells and mature dendritic cells has been subjected to a quantitative analysis. Immunofluorescence images of synapses formed in the absence of antigen show a diffuse synaptic accumulation of CD3 and LFA-1. In electron microscopy, these antigen-free synapses present a number of tight appositions (cleft size approximately 15 nm), all along the synapse. These tight appositions cover a significantly larger surface fraction of antigen-dependent synapses. In immunofluorescence, antigen-dependent synapses show multiple patches of CD3 and LFA-1 with a variable overlap. A similar distribution is observed for PKCtheta and talin. A concentric organization characteristic of prototypical synapses is rarely observed, even when dendritic cells are paralyzed by cytoskeletal poisons. In T-DC synapses, the interaction surface is composed of several tens of submicronic contact spots, with no large-scale segregation of CD3 and LFA-1. As a comparison, in T-B synapses, a central cluster of CD3 is frequently observed by immunofluorescence, and electron microscopy reveals a central tight apposition. Our data show that it is inappropriate to consider the concentric structure as a "mature synapse" and multifocal structures as immature.
对小鼠天然T细胞与成熟树突状细胞之间形成的免疫突触结构进行了定量分析。在无抗原情况下形成的突触的免疫荧光图像显示CD3和LFA-1在突触处呈弥漫性积累。在电子显微镜下，这些无抗原突触在整个突触中呈现出许多紧密并列结构（裂隙大小约为15纳米）。这些紧密并列结构覆盖的表面积在抗原依赖性突触中显著更大。在免疫荧光中，抗原依赖性突触显示出多个CD3和LFA-1斑块，重叠情况各异。PKCtheta和踝蛋白也观察到类似分布。即使树突状细胞被细胞骨架毒物麻痹，也很少观察到典型突触的同心组织特征。在T-DC突触中，相互作用表面由数十个亚微米级接触点组成，CD3和LFA-1没有大规模分离。作为比较，在T-B突触中，通过免疫荧光经常观察到CD3的中央簇，电子显微镜显示有中央紧密并列结构。我们的数据表明，将同心结构视为“成熟突触”而将多焦点结构视为不成熟是不合适的。
