Daha M R, Gorter A, Leijh P J, Klar N, van Es L A
Department of Nephrology and Infectious Diseases, University Hospital, Leiden, The Netherlands.
Immunology. 1988 Jul;64(3):375-9.
Mononuclear cells play an important role in the elimination of immune complexes (IC). In the presence of complement (C) the binding and degradation of IC by mononuclear cells is enhanced at least two-fold. The enhancement of binding is caused by a synergistic interaction of the IC with cellular Fc and complement receptors (R). In the present study we have investigated the contribution of the complement receptors CR1 and CR3 of human monocyte cell line U937 on the complement-mediated binding and degradation of immune complexes and soluble aggregates of IgG (AIgG) bearing C3b or iC3b. It was found that deposition of C3b on AIgG enhanced the binding of AIgG to U937 cells at least two-fold. The C3b-mediated enhancement of binding was abolished by anti-CR1. iC3b-bound to AIgG also enhanced the binding of AIgG to the cells. This binding was only partially reduced by anti-CR3 antibodies, but the combination of anti-CR1 and anti-CR3 fully abolished the iC3b-mediated enhancement of binding. These results suggest that both CR1 and CR3 contribute to the complement-mediated binding and degradation of soluble IC by mononuclear phagocytes.
单核细胞在免疫复合物（IC）的清除中起重要作用。在补体（C）存在的情况下，单核细胞对IC的结合和降解增强至少两倍。结合的增强是由IC与细胞Fc和补体受体（R）的协同相互作用引起的。在本研究中，我们研究了人单核细胞系U937的补体受体CR1和CR3对补体介导的免疫复合物以及带有C3b或iC3b的IgG可溶性聚集体（AIgG）的结合和降解的作用。发现C3b在AIgG上的沉积使AIgG与U937细胞的结合增强至少两倍。抗CR1可消除C3b介导的结合增强。与AIgG结合的iC3b也增强了AIgG与细胞的结合。抗CR3抗体只能部分降低这种结合，但抗CR1和抗CR3的组合可完全消除iC3b介导的结合增强。这些结果表明，CR1和CR3都有助于单核吞噬细胞对可溶性IC的补体介导的结合和降解。
