APOE and atherosclerosis: As Xcr1 is the sole receptor for Xcl1, and Xcl1 selectively attracts Xcr1+ cDC1 cells in both mice and humans (Yoshida et al., 1999; Yoshida et al., 1998), we performed Xcl1 knockout on the background of Apoe–/– mice and assessed the impact on atherosclerosis development.