Delibrias C C, Mouhoub A, Fischer E, Kazatchkine M D
INSERM U28, Hôpital Broussais, Paris, France.
Eur J Immunol. 1994 Nov;24(11):2784-8. doi: 10.1002/eji.1830241131.
The present study demonstrates that the C3b receptor CR1 (CD35) and the C3dg/Epstein-Barr virus receptor CR2 (CD21) are expressed by 25% and 70% of normal human thymocytes, respectively. The expression of CR2 extends to both CD1+ and CD1- cells in the thymus. Two subsets of CR2+ thymocytes were defined expressing low and high density of the receptor. The CR2++ subset represented 20% of CR2+ thymocytes and co-expressed the CR1 receptor. CR2++ thymocytes expressed an immature CD1dull, CD3-, CD4dull, CD8-, CD7++ phenotype and included a subpopulation of large cells expressing CD34. Twenty percent of thymocytes expressed the CD21 epitope defined by monoclonal antibody BU32, which is involved in the binding of CD23 to CD21. These observations provide a basis for a role for CD21 in the proliferation and differentiation of thymocytes at early stages of maturation. The functionality of CR1 and CR2 on thymocytes was evidenced by the ability of the receptors to mediate infection of cells with complement-opsonized human immunodeficiency virus (HIV). The results may be relevant to the immunopathogenesis of HIV infection.
本研究表明，补体C3b受体CR1（CD35）和C3dg/EB病毒受体CR2（CD21）分别在25%和70%的正常人胸腺细胞中表达。CR2的表达扩展至胸腺中的CD1+和CD1-细胞。定义了CR2+胸腺细胞的两个亚群，分别表达低密度和高密度的该受体。CR2++亚群占CR2+胸腺细胞的20%，并共表达CR1受体。CR2++胸腺细胞表达不成熟的CD1dull、CD3-、CD4dull、CD8-、CD7++表型，且包括一群表达CD34的大细胞亚群。20%的胸腺细胞表达由单克隆抗体BU32定义的CD21表位，该表位参与CD23与CD21的结合。这些观察结果为CD21在胸腺细胞成熟早期的增殖和分化中发挥作用提供了依据。胸腺细胞上CR1和CR2的功能通过这些受体介导补体调理的人类免疫缺陷病毒（HIV）感染细胞的能力得到证实。这些结果可能与HIV感染的免疫发病机制相关。
