CD40 and CD40 ligand coexpression on human endothelial cells and in human atherosclerotic plaque lesions

AIM: To investigate whether human umbilical vein endothelial cells and human atherosclerotic plaque lesions can coexpress CD40 and CD40 ligand . METHODS: The expression of CD40 and its ligand CD40L on human endothelia cells were measured by fluorescence microscope , flow cytometry(FCM), reverse transcription PCR(RT-PCR) and Western blotting, respectively. Both CD40 and CD40L expression in atheroma plaques were determined by immunohistochemistry. RESULTS: Cultured human endothelial cells constitutively coexpressed CD40 and CD40L in mRNA and protein levels. Stimulation with interleukin-1β, interleukin-6, tumor necrosis factor-α and interferon-γ increased expression of CD40 and CD40L on endothelial cells . Human atherosclerotic lesions( n =6) showed coexpression of immunoreactive CD40 and CD40L. However, no expression of CD40 and CD40L in nonatherosclerotic human arteries. CD40L mainly expressed on the shoulder and base of the plaque. But CD40 was widespreadly expressed in plaque. CONCLUSION: Our results demonstrated that CD40 and CD40L coexpressed on human umbilical vein endothelial cells and in human atherosclerotic plaque lesions. These findings suggest a previously unsuspected role for CD40-CD40L interactions in atherosclerosis.