Species differences in the expression of major histocompatibility complex class II antigens on coronary artery endothelium: implications for cell-mediated xenoreactivity.
BACKGROUND
There is controversy in the literature as to whether swine coronary endothelium expresses major histocompatibility complex (MHC) class II antigens constitutively.


METHODS
Because this issue has implications for cell-mediated human anti-swine xenogeneic responses, we stained tissue sections from human, pig, rat, and mouse hearts with the anti-class II monoclonal antibody ISCR3, which has a similar specificity and titer when binding to human, porcine, and rodent class II molecules.


RESULTS
Immunoperoxidase staining of human and porcine hearts with ISCR3 resulted in a dense reaction on the coronary endothelium of epicardial arteries, intramuscular arterioles, and capillaries. In contrast, the coronary endothelium of rat and mouse hearts did not stain with ISCR3. When freshly harvested porcine aortic endothelial cells were placed in culture, class II MHC antigen expression was lost within three to four passages.


CONCLUSIONS
Thus, using a single antibody with cross-species reactivities, we demonstrate that swine coronary endothelium, unlike rodent coronary arteries, expresses similar basal amounts of class II MHC antigens to human coronary vessels. The constitutive expression of class II MHC antigens on swine coronary artery endothelium may contribute to host T cell-mediated xenogeneic responses in clinical pig-to-human cardiac xenotransplantation and thus become a target for therapeutic intervention.
Choo
J K
JK
Transplantation Biology Research Center, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
Seebach
J D
JD
Nickeleit
V
V
Shimizu
A
A
Lei
H
H
Sachs
D H
DH
Madsen
J C
JC
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D002460:Cell Line; D003331:Coronary Vessels / Q000276:immunology* / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000276:immunology* / Q000378:metabolism*; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis* / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology; D051379:Mice; D009206:Myocardium / Q000276:immunology / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D013045:Species Specificity; D013552:Swine; D014183:Transplantation, Heterologous / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II