Expression of interleukin-15 in mouse and human atherosclerotic lesions.
Atherosclerotic lesions are characterized by prominent macrophage and T-cell infiltration and atherosclerosis is widely recognized as an inflammatory disease. The cytokine interleukin-15 (IL-15) has T-cell chemotactic and pro-inflammatory properties and promotes the recruitment of T cells to sites of inflammation. We have therefore examined IL-15 expression in the atherosclerotic ApoE-deficient mouse model as well as in human atherosclerotic lesions. In gene expression arrays, a transcript corresponding to IL-15 mRNA was elevated in atherosclerotic aortas of ApoE-deficient mice fed a Western diet for 10 and 20 weeks, corresponding to lesions of the fatty streak and fibrofatty plaque stage, respectively. Immunostaining for IL-15 localized to aortic smooth muscle cells in nonatherosclerotic C57BL/6 mice, whereas both macrophages and smooth muscle cells stained positive for IL-15 in atherosclerotic lesions of ApoE-deficient mice. Finally, advanced atherosclerotic lesions of human carotid arteries were immunostained to determine whether IL-15 is involved in human disease. IL-15 protein was present also in the human lesions with a distribution primarily overlapping that of macrophages. In conclusion, IL-15 is up-regulated in both human and animal atherosclerotic lesions and may contribute to the recruitment of T cells and their activation during atherogenesis.
Wuttge
D M
DM
Department of Medicine, Karolinska Hospital, Karolinska Institute, S-171 76 Stockholm, Sweden.
Eriksson
P
P
Sirsjö
A
A
Hansson
G K
GK
Stemme
S
S
D000375:Aging; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000276:immunology* / Q000473:pathology; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D001161:Arteriosclerosis / Q000235:genetics* / Q000276:immunology* / Q000473:pathology; D004032:Diet; D006801:Humans; D007150:Immunohistochemistry; D019409:Interleukin-15 / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000276:immunology* / Q000473:pathology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D014158:Transcription, Genetic
D001057:Apolipoproteins E; D019409:Interleukin-15; D012333:RNA, Messenger