OBJECTIVE - Accelerated atherosclerosis is a major source of morbidity in systemic lupus erythematosus (SLE). However, the cause of SLE-accelerated atherosclerosis remains unclear.
METHODS - CD4(+) T cells from C57/Bl/6 (B6) or SLE-susceptible B6.Sle1.2.3 (B6.SLE) mice were transferred into LDLr(-/-), Rag(-/-) mice. T cells were examined for cytokine production and expression of interleukin-10 receptor (IL-10R) and functional markers. T cells were isolated based on FoxP3(GFP) expression and transferred to LDLr(-/-), Rag(-/-) mice to establish a role for B6.SLE effector T cells (Teff) in atherosclerosis.
RESULTS - Mice receiving whole B6.SLE CD4(+) T cells displayed no other SLE phenotype; however, atherosclerosis was increased nearly 40%. We noted dysregulated IL-17 production and reduced frequency of IL-10R expression by B6.SLE regulatory T cells (Treg). Functional assays indicated resistance of B6.SLE Teff to suppression by both B6.SLE and B6 Treg. Transfer experiments with CD4(+)FoxP3(-) Teff and CD4(+)FoxP3(+) Treg from B6.SLE and B6 mice, respectively, resulted in increased atherosclerosis compared with B6 Teff and Treg recipients. Treg isolated from mice receiving B6.SLE Teff with B6 Treg had increased production of IL-17 and fewer expressed IL-10R compared with B6 Teff and Treg transfer.
CONCLUSIONS - Transfer of B6.SLE Teff to LDLr(-/-), Rag(-/-) mice results in accelerated atherosclerosis independent of the source of Treg. In addition, the presence of B6.SLE Teff resulted in more IL-17-producing Treg and fewer expressing IL-10R, suggesting that B6.SLE Teff may mediate phenotypic changes in Treg. To our knowledge, this is the first study to provide direct evidence of the role of B6.SLE Teff in accelerating atherosclerosis through resistance to Treg suppression.
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