SIGLEC1 and infection: We demonstrate that the HIV attachment factor, SIGLEC1/CD169, plays a role in enhancing infection in THP-1 cells in cis rather than the more fully described role of SIGLEC1 to mediate infection from dendritic cells to T cells in trans (Izquierdo-Useros et al., 2012; Puryear et al., 2013).