Generation of HSP60-specific regulatory T cell and effect on atherosclerosis

Although CD4+CD25+ regulatory T cells are pivotal in the suppression of autoimmunity, little is known about the effect of antigen-specific regulatory T cells on the formation of atheromatous plaques. Here, we describe the induction of heat-shock protein 60 (HSP60)-specific CD4+CD25high T cells by rapamycin (RPM)-treated immature dendritic cells in vitro and explore their effect on plaques in apolipoprotein E-deficient mice. Rapamycin-treated bone marrow-derived dendritic cells (DC) were immature, expressing a low level of co-stimulation factors CD86 and CD80. Naive CD4+ T cells expressed high levels of CD25 and forkhead box P3 (Foxp3) after incubation with rapamycin-treated and HSP60-loaded DC and displayed moderate antigen-specific, IL-10-independent inhibitory function in vitro. After adoptive transfer, HSP60-specific CD4+CD25high T cells inhibited the formation of plaques, while ovalbumin-specific cells did not. These findings suggest that RPM-treated DC can induce antigen-specific CD4+CD25high Treg cells that have inhibitory activity in vitro and prevent the development of plaques in vivo.