血浆蛋白可屏蔽人类循环中IgG抗体对凋亡细胞的反应活性

Circulating human IgG reactive to apoptotic cells are masked by plasma proteins

目的明确血浆蛋白影响循环中IgG抗体对凋亡细胞的反应性,并探索检测此类抗体活性的最佳条件。方法分别检测纯化前及纯化后的IgG抗体对凋亡细胞的反应性。检测所用样本来源于:(1)10例发生移植肾抗体介导排异反应(AMR)患者的血浆样本;(2)从以上10例患者血浆中纯化的IgG抗体;(3)分泌IgG抗体的永生化B淋巴细胞克隆培养上清液;(4)从同一永生化B淋巴细胞克隆培养上清液中纯化的IgG抗体。结果当IgG从血浆中纯化出来时,其对凋亡细胞的反应性显著增强。对于某些单克隆B细胞分泌的IgG抗体,只有将此抗体从细胞培养上清液中纯化,才能检测到其对凋亡细胞的反应性。而胎牛血清(FCS)可部分阻滞纯化IgG抗体对凋亡细胞的反应性。结论当血浆蛋白存在时,循环中IgG抗体对凋亡细胞的反应性可被屏蔽。在检测此类抗体的活性时,有必要将其从血浆中纯化出来以提高检测的准确性。

Objective To confirm the influence of plasma proteins on the reactivity of circulating IgG to apoptotic cells and to develop an optimal methodology for studying these antibodies.Methods IgG reactivity to apoptotic cells was assessed before and after purification.The following sources of IgG were used：（1）Plasma specimens from 10 kidney transplant recipients with AMR;（2）purified IgG from the same 10 AMR patients;（3）supernatant from IgG-producing immortalized B cell clones;（4）purified IgG from the same B cell clone supernatants.Results Results Plasma IgG reactivity to apoptotic cells was dramatically increased following purification.We observed that reactivity to apoptotic cells could only be detected after purification for some monoclonal IgG produced by B cell clones.Fetal calf serum（FCS）partially reversed the apoptotic-binding potential of purified IgG.Conclusion The reactivity of circulating IgG to apoptotic cells is modified in the presence of plasma proteins.These antibodies must first be purified to remove plasma proteins in order to accurately assess their reactivity.