After genital administration to macaques, SIV establishes foci of infection in the vaginal sub-mucosa within a matter of days through a scheme involving macrophage inflammatory protein-3alpha (MIP-3α) (CCL20) production by ECs and early recruitment of interferon-alpha (IFN-α) producing plasmacytoid DC (pDC) as well as DC and CD4+ T-cell effectors, rapidly accessing draining lymph nodes and establishing systemic invasion by days 10–14. The gene discussed is CCL20; the disease is infection.