SIGLEC1 and HIV-1 infection: Knockdown of RIG-I and MDA5 (Fig. 5f and Supplementary Fig. 5a) affected neither susceptibility to HIV-1 infection (Fig. 5g, h and Supplementary Fig. 5d, e) nor enhancement of CD169 expression upon HIV-1 infection in MDMs (Fig. 5i, j and Supplementary Fig. 5d, e), implying there is a yet-to-be identified RNA sensor detecting HIV-1 icRNA.