Haegert D G
Clin Exp Immunol. 1979 Mar;35(3):484-90.
Phagocytic human and rabbit peripheral blood monocytes, identified by their ingestion of polystyrene particles, were investigated for the presence of surface membrane receptors for IgM molecules. After incubation of freshly isolated monocytes with IgM anti-sheep erythrocyte (SRBC) preparations, a mean of 0.7% of human monocytes and a mean of 16.2% of rabbit monocytes formed rosettes with SRBC. However, if the monocytes were pre-incubated with vibrio cholerae neuraminidase (VCN), these figures increased to 32.6% and 37.8% respectively. The specificity of rosette formation by VCN-treated monocytes was established in several experiments; SRBC sensitized with a F(ab')2 preparation of an IgG anti-SRBC reagent completely failed to rosette with VCN-treated monocytes, and inclusion of IgM, but not other Ig or non-Ig protein molecules in the test medium, inhibited rosette formation. Further, and most important, rosette formation by human monocytes was inhibited by F(c)5mu but not by Fabmi fragments. These findings indicate that both rabbit and human monocytes express IgM-class specific membrane receptors for IgM molecules, that these receptors may be cryptic or hidden but can be revealed by treatment with VCN and that the human monocyte IgM receptor is F(c) specific. Further, the rabbit monocyte IgM receptor was shown to be trypsin-resistant.
通过摄取聚苯乙烯颗粒鉴定的人及兔外周血吞噬单核细胞，被研究是否存在IgM分子的表面膜受体。将新鲜分离的单核细胞与IgM抗绵羊红细胞（SRBC）制剂孵育后，平均0.7%的人单核细胞和平均16.2%的兔单核细胞与SRBC形成花环。然而，如果单核细胞预先用霍乱弧菌神经氨酸酶（VCN）孵育，这些数字分别增加到32.6%和37.8%。在几个实验中确定了VCN处理的单核细胞形成花环的特异性；用IgG抗SRBC试剂的F(ab')2制剂致敏的SRBC完全不能与VCN处理的单核细胞形成花环，并且在测试培养基中加入IgM而非其他Ig或非Ig蛋白分子会抑制花环形成。此外，也是最重要的，人单核细胞形成花环受到F(c)5μ的抑制，但不受Fabμ片段的抑制。这些发现表明，兔和人单核细胞都表达针对IgM分子的IgM类特异性膜受体，这些受体可能是隐蔽的或隐藏的，但可以通过VCN处理而暴露，并且人单核细胞IgM受体是F(c)特异性的。此外，兔单核细胞IgM受体显示对胰蛋白酶有抗性。
