CORONARY ATHEROSCLEROSIS IN TRANSPLANTED MOUSE HEARTS .1. TIME-COURSEAND IMMUNOGENETIC AND IMMUNOPATHOLOGICAL CONSIDERATIONS

An experimental system is described ill which coronary arteries of mou se hearts transplanted heterotopically develop obstructive lesions by 4 weeks. Transient immunosuppression permits graft survival. Donor/rec ipient antigenic differences may be either class I or class II major h istocompatibility antigens (H-2) or non-H-2 antigens. An infiltrate in cluding CD4(+) and CD8(+) T lymphocytes and macrophages concentrates e arly, in the intima and adventitia of larger coronary arteries, with l ittle in the myocardium. Subsequently, the intima expands with cells o f donor origin and the infiltrate invades the media. Endothelial and i ntimal cells express ICAM-1, leukocytes LFA-1. Endothelium expresses c lass I, but not class II, antigens. As class II disparity alone suffic es, the endothelium can apparently be all indirect target of immune in jury. We propose that graft atherosclerosis is T cell initiated and el icited by heterogeneous antigens in the endothelium or media. It is se parable from rejection of the myocardium.