Lymphocyte activation induces cell surface expression of an immunogenic vimentin isoform.
High titers of anti-vimentin antibodies after transplantation are known to be associated with poor long-term graft survival. Vimentin is an intracellular protein which is present in different isoforms in the cell. In a previous study with sera from hemodialysis patients on the kidney transplantation waiting list we could show that only a 49 kDa and a 60 kDa isoform are recognized by patients' anti-vimentin antibodies while the other isoforms remain undetected. However, it is still unclear whether antibodies against this intracellular protein can bind to intact cells. Here we show that vimentin can be present on the cell surface under certain conditions. Lymphocytes from healthy volunteers were used as a model for allogeneic cells. We could show by immunofluorescence microscopy, flow cytometry and Western blot experiments that concanavalin A (Con A) activated lymphocytes express a 49 kDa vimentin isoform on their cell surface while the 60 kDa isoform remains inaccessible from the outside. This expression is associated with an increased binding of sera from hemodialysis patients which were positive for anti-vimentin antibodies. These results suggest that cell activation enhances binding of anti-vimentin antibodies to intact cells which might contribute to chronic allograft nephropathy.
Department of Surgery, Medical University of Vienna, A-1090 Vienna, Austria.
Senada
S
Bilalic
Anna
A
Michlmayr
Viktoria
V
Gruber
Elisabeth
E
Buchberger
Christopher
C
Burghuber
Georg A
GA
Böhmig
Rudolf
R
Oehler
D000328:Adult; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D002908:Chronic Disease; D005260:Female; D006084:Graft Rejection / Q000209:etiology / Q000276:immunology*; D006801:Humans; D007518:Isoantibodies / Q000276:immunology / Q000378:metabolism; D007676:Kidney Failure, Chronic / Q000276:immunology* / Q000628:therapy; D016030:Kidney Transplantation; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D011485:Protein Binding / Q000276:immunology; D020033:Protein Isoforms / Q000276:immunology / Q000378:metabolism*; D006435:Renal Dialysis; D014746:Vimentin / Q000276:immunology / Q000378:metabolism*; D014850:Waiting Lists
D007518:Isoantibodies; D020033:Protein Isoforms; D014746:Vimentin