Autoimmunity to vimentin potentiates graft vasculopathy in murine cardiac allografts.
BACKGROUND
There is increasing evidence for a role for autoimmunity in transplant rejection. It has previously been shown that autoantibodies to vimentin (Vim) accelerate acute rejection of murine cardiac allografts. We have investigated whether autoimmunity to Vim contributes to development of cardiac allograft vasculopathy (CAV).


METHODS
Two well-established minor mismatch murine models of CAV were used, transplantation of 129/sv hearts into T-cell-depleted C57Bl/6 (B6) recipients and transplantation of FVB hearts into nonimmunosuppressed DBA/1 recipients. Recipients were immunized with recombinant mouse Vim in complete Freunds adjuvant, and controls received hen egg lysozyme 2 weeks before transplantation. T cell and antibody responses to Vim were assessed by ELISPOT and ELISA, respectively. CAV within transplanted hearts was assessed by quantitative morphometry of occluded vessels, presence of smooth muscle cells, deposition of C3d, and confocal microscopy.


RESULTS
Allografts were harvested from B6 recipients at days 30 and 45 and from DBA/1 recipients at days 18 and 35. At all days, there was significantly more intimal occlusion of arteries of Vim -immunized mice than controls. There was significantly more smooth muscle cell alpha actin in vessels from Vim-immunized mice, and more C3d deposited in hearts from Vim-immunized mice. Confocal microscopy demonstrated colocalization of Vim with C3d on endothelial cells, leukocytes, and platelets in allogeneic but not syngeneic hearts. Serum from Vim-immunized mice, but not controls, caused platelet/leukocyte conjugation when added to mouse leukocytes.


CONCLUSIONS
The autoimmune response to Vim accelerates CAV progression in these minor-mismatched models.
Mahesh
Balakrishnan
B
National Heart and Lung Institute, Imperial College, Heart Science Centre, Harefield Hospital, Harefield, United Kingdom.
Leong
Hon-Sing
HS
Nair
K Sukumaran
KS
McCormack
Ann
A
Sarathchandra
Padmini
P
Rose
Marlene L
ML
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015551:Autoimmunity / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D006084:Graft Rejection / Q000473:pathology; D016027:Heart Transplantation / Q000276:immunology* / Q000473:pathology; D006650:Histocompatibility Testing; D007962:Leukocytes / Q000187:drug effects / Q000276:immunology; D008212:Lymphocyte Depletion; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D018613:Microscopy, Confocal; D015778:Minor Histocompatibility Antigens / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D016042:Transplantation, Heterotopic / Q000276:immunology; D014184:Transplantation, Homologous / Q000276:immunology*; D014185:Transplantation, Isogeneic / Q000276:immunology*; D014746:Vimentin / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015778:Minor Histocompatibility Antigens; D011994:Recombinant Proteins; D014746:Vimentin