In addition, CD169, which is also known as sialoadhesin or sialic acid-binding immunoglobulin-like lectin-1 (Siglec-1), is exclusively expressed on specific subpopulations of macrophages (Delputte et al.2011) and is considered to be an accessory protein involved in the infection process of the PRRSV. Here, SIGLEC1 is linked to infection.