The present invention provides liposome targeting compounds for targeting cells expressing sialic acid binding Ig-like lectin (Siglec). The liposome compounds typically comprise a binding moiety that is a glycan ligand of the Siglec on the target cell. The liposome compounds also incorporate or encapsulate a biological agent (e.g., an antigen or a therapeutic agent) that can be delivered to the target cell to modulate or kill the target cell. The invention also provides methods of using the liposome targeting compounds for targeted delivery of antigen and for modulating immune cells or immune responses.