Abstract: Objective To study whether Fcα/μR can mediate complement killing of human glomerular mesangial cells. Methods The Fcα/μR cDNA contained plasmid, pcDNA3.1-Fcα/μR was transfected into a human glomerular mesangial cell line, NHMC. Fcα/μR expression was detected by Western blotting and laser scanning confocal microscopic analysis. Binding of IgM-immune complexes (IgM-IC) to the Fcα/μR on cell membrane was detected by flowcytometry and laser scanning confocal microscopyic analysis. Killing of cells by complement was analyzed by Trypan blue exclusion assay. Results NHMC cells transfected with Fcα/μR could bind IgM and IgM-IC. After treatment with complement, added IgM-IC, the death rate of pcDNA3.1-Fcα/μR transfected cell was significant higher than the control groups of wild type cell, pcDNA3.1 transfected cell and the pcDNA3.1-Fcα/μR transfected cell without IgM-IC. Conclusion IgM-IC can be bound by Fcα/μR expressed NHMC cells and mediate complement killing of the cells.

Key words: Fcα/μR, IgM, Immune complexes, complement, glomerular mesangial cell