Fig. 1.

Antigen presentation and induction of antigen-specific pathogenic and regulatory T cells in the context of atherosclerosis. Antigen presentation most likely occurs within the secondary lymphoid organs, and primed T cells are reactivated within the lesions. DC activation and maturation by self-altered structures, in part through toll-like receptors (TLRs), lead to induction/maintenance of pathogenic immunity. Phagocytic clearance of apoptotic debris through milk fat globule-EGF factor 8 (Mfge8) or mer tyrosine kinase receptor (mertk) is required for induction/maintenance of regulatory immunity. The proinflammatory plaque environment is permissive to the induction/maintenance of pathogenic T cells but impairs the development of regulatory immunity. Thus, in order to maintain a Treg cell response, DCs would need to continuously traffic to peripheral lymphoid organs.