Sandrin M S, Mouhtouris E, Vaughan H A, Warren H S, Parish C R
Molecular Immunogenetics Laboratory, Austin Research Institute, Austin Hospital, Heidelberg, Victoria, Australia.
J Immunol. 1993 Nov 1;151(9):4606-13.
COS cells transiently transfected with human CD48 were found to bind human PBL, whereas mock or CD7-transfected COS cells failed to bind human lymphocytes. Binding of PBL to CD48 transfectants was almost totally inhibited by either CD48 mAb pretreatment of COS cells or CD2 mAb pretreatment of PBL, implying an interaction between CD2 and CD48. This conclusion was confirmed by the demonstration that a highly fluorescent, multimeric form of rCD2 bound to CD48 transfected COS cells in a CD48-dependent manner. Additional mAb blocking studies revealed that CD48 interacts with the T11(1) region of CD2, the same region of CD2 that binds LFA-3 (CD58). Thus, CD48 and CD58 represent alternative and possibly competing ligands for CD2, although based on blocking studies with soluble CD2, CD48 interacts with CD2 with approximately a 100-fold lower affinity that CD58.
研究发现，瞬时转染人CD48的COS细胞能够结合人外周血淋巴细胞（PBL），而mock转染或转染CD7的COS细胞则无法结合人淋巴细胞。COS细胞经CD48单克隆抗体预处理或PBL经CD2单克隆抗体预处理后，PBL与CD48转染细胞的结合几乎完全受到抑制，这表明CD2与CD48之间存在相互作用。这一结论通过以下实验得到证实：一种高荧光的多聚体形式的重组CD2以CD48依赖的方式与转染CD48的COS细胞结合。进一步的单克隆抗体阻断研究表明，CD48与CD2的T11(1)区域相互作用，该区域也是CD2与淋巴细胞功能相关抗原-3（LFA-3，即CD58）结合的区域。因此，CD48和CD58是CD2的替代性且可能相互竞争的配体，不过基于可溶性CD2的阻断研究，CD48与CD2相互作用的亲和力比CD58低约100倍。
