Model of DC migration and sequential effector-cell attraction. Blood DCs expressing, at the steady state, CXCR4 and CXCR3, can migrate through virally infected tissues, expressing CXCL12, CXCL9, CXCL10, and CXCL11. There, they can penetrate the tissues. Upon encountering the virus, they start to release at the first step CXCL16, CXCL1, CXCL2, CXCL3, CXCL7, and CXCL8. These CKs attract Th1 effectors cells expressing CXCR6 and neutrophils expressing CXCR2 (no. 1 in figure). Later, activated DCs secrete CCL2, CCL3, CCL4, CCL5, and CCL8, which essentially attract CCR5-expressing memory T lymphocytes and monocytes (no. 2). Upon maturation, DCs up-regulate CCR7 and down-regulate CXCR4, allowing, with l-selectin expression, their migration to high endothelial venules expressing CCL21 in lymphoid organs. In the T-cell area, activated pDCs secrete CCL19 and CXCL13, which respectively attract CCR7-expressing naive T cells and CXCR5-expressing naive B cells (no. 3). They also secrete CCL22, attracting CCR4-expressing Th2 and CD4⁺CD25⁺ regulatory cells (no. 3).