Schulz O, Laing P, Sewell H F, Shakib F
Division of Molecular and Clinical Immunology, University of Nottingham Medical School, Queen's Medical Centre, GB.
Eur J Immunol. 1995 Nov;25(11):3191-4. doi: 10.1002/eji.1830251131.
The nature of the proteases that cleave CD23 in vivo is of considerable interest, but remains unknown. Here, we demonstrate that Der p I, a major allergen of the house dust mite Dermatophagoides pteronyssinus, cleaves CD23 from the surface of cultured human B cells (RPMI 8866 B cell line). The cleavage of the receptor from the B cell surface was associated with a parallel increase in soluble CD23 (sCD23) in the culture supernatant. Furthermore, the proteolytic effect of Der p I was specific for CD23, since none of the other B cell markers tested (CD20, HLA-DR, CD71 and CD49d) were affected. Labeled antibody experiments and protease inhibition assays clearly demonstrate that Der p I is a cysteine protease that directly cleaves a 25-kDa fragment of CD23. These data suggest that the cysteine protease Der p I, in addition to being highly immunogenic, may up-regulate IgE synthesis by virtue of its ability to cleave CD23.
在体内裂解CD23的蛋白酶的性质备受关注，但仍不清楚。在此，我们证明了来自屋尘螨变应原性螨的主要变应原Der p I，可从培养的人B细胞（RPMI 8866 B细胞系）表面裂解CD23。B细胞表面受体的裂解与培养上清液中可溶性CD23（sCD23）的平行增加相关。此外，Der p I的蛋白水解作用对CD23具有特异性，因为所测试的其他B细胞标志物（CD20、HLA-DR、CD71和CD49d）均未受影响。标记抗体实验和蛋白酶抑制试验清楚地表明，Der p I是一种半胱氨酸蛋白酶，可直接裂解CD23的一个25 kDa片段。这些数据表明，半胱氨酸蛋白酶Der p I除具有高度免疫原性外，还可能因其裂解CD23的能力而上调IgE合成。
