Gaither T A, Magrath I T, Berger M, Hammer C H, Novikovs L, Santaella M, Frank M M
J Immunol. 1983 Aug;131(2):899-905.
Complement receptor (CR) expression in cell lines derived from Burkitt's lymphoma (BL), Epstein Barr virus-transformed cord blood lymphocytes (CB), and peripheral lymphocytes from patients with infectious mononucleosis (IM) was examined. Red cell intermediates bearing various densities of C4b, C3b, C3bi, or C3d were tested for rosette formation with the cell lines. In addition, a series of studies was performed under conditions that precluded the cleavage of cellbound C3b by Factor I (C3bINA). These conditions did not alter rosetting by the cells that were tested. RAJI cells rosetted with EAC3bi greater than EAC3d greater than EAC3b, but not with EAC4b. EAC3b/RAJI rosette formation required much greater quantities of C3b bound to red cells than did CB and IM lines, which unlike RAJI, also bound EAC4b. All of the BL lines failed to bind EAC4b even at a C4b density of 50,000 molecules/cell, but several lines did form rosettes with EAC3b, and most formed rosettes with EAC3bi and EAC3d. Fluid phase C3b blocked RAJI/EAC3b rosetting while having little effect on RAJI/EAC3bi rosette activity. Moreover, fluid phase C3b, as well as C4b, blocked RAJI/EAC3b rosettes more effectively than CB/EAC3b rosettes. The results indicate that the RAJI cell line has a receptor for C3b, with characteristics that differ markedly from the C3b receptor of cell lines derived from CB lymphocytes and of lymphoblastoid cell lines derived from patients with IM. This receptor is capable of interacting with soluble but not cellbound C4b. In these studies, rosette formation was examined under various ionic conditions. RAJI/EAC3b rosette formation was severely reduced as ionic strength was increased, whereas RAJI/EAC3bi binding was only moderately decreased at physiologic ionic strength. In striking contrast, EAC3bi binding to monocytes, PMN, and human erythrocytes was markedly reduced as ionic strength increased, but EAC3b binding to these cells was less sensitive to changes in ionic strength. Under conditions of physiologic ionic strength, the C3bi receptor of phagocytic cells may be at a functional disadvantage in the binding of C3bi-coated particles. This may have major physiologic implications.
检测了源自伯基特淋巴瘤（BL）、爱泼斯坦-巴尔病毒转化的脐血淋巴细胞（CB）以及传染性单核细胞增多症（IM）患者外周淋巴细胞的细胞系中补体受体（CR）的表达。用携带不同密度C4b、C3b、C3bi或C3d的红细胞中间体检测与这些细胞系的玫瑰花结形成情况。此外，在排除I因子（C3bINA）对细胞结合的C3b裂解的条件下进行了一系列研究。这些条件并未改变所检测细胞的玫瑰花结形成。RAJI细胞与EAC3bi形成玫瑰花结的能力大于EAC3d大于EAC3b，但不与EAC4b形成玫瑰花结。与CB和IM细胞系不同，EAC3b/RAJI玫瑰花结形成所需结合到红细胞上的C3b量要多得多，CB和IM细胞系还能结合EAC4b。所有BL细胞系即使在C4b密度为50,000个分子/细胞时也不能结合EAC4b，但有几个细胞系能与EAC3b形成玫瑰花结，大多数能与EAC3bi和EAC3d形成玫瑰花结。液相C3b可阻断RAJI/EAC3b玫瑰花结形成，而对RAJI/EAC3bi玫瑰花结活性影响较小。此外，液相C3b以及C4b阻断RAJI/EAC3b玫瑰花结的效果比阻断CB/EAC3b玫瑰花结更有效。结果表明，RAJI细胞系具有C3b受体，其特性与源自CB淋巴细胞的细胞系以及源自IM患者的淋巴母细胞系的C3b受体明显不同。该受体能够与可溶性C4b相互作用，但不能与细胞结合的C4b相互作用。在这些研究中，在各种离子条件下检测了玫瑰花结形成情况。随着离子强度增加，RAJI/EAC3b玫瑰花结形成严重减少，而RAJI/EAC3bi结合仅在生理离子强度下适度降低。与之形成鲜明对比的是，随着离子强度增加，EAC3bi与单核细胞、PMN和人红细胞的结合明显减少，但EAC3b与这些细胞的结合对离子强度变化不太敏感。在生理离子强度条件下，吞噬细胞的C3bi受体在结合C3bi包被颗粒方面可能处于功能劣势。这可能具有重要的生理意义。
