May have a pivotal role in cell differentiation of different cell types. Signaling could be triggered by the binding of a lectin-like ligand to the CD24 carbohydrates, and transduced by the release of second messengers derived from the GPI-anchor. Modulates B-cell activation responses. Promotes AG-dependent proliferation of B-cells, and prevents their terminal differentiation into antibody-forming cells (PubMed:11313396). In association with SIGLEC10 may be involved in the selective suppression of the immune response to danger-associated molecular patterns (DAMPs) such as HMGB1, HSP70 and HSP90. Plays a role in the control of autoimmunity (By similarity). Interacts with LYN and FGR in a cell-type specific manner. Binds FRG in a small cell cancer line, LYN in the erythroleukemia cell line K-562 and in Burkitt's lymphoma. B-cells. Expressed in a number of B-cell lines including P32/ISH and Namalwa. Expressed in erythroleukemia cell and small cell lung carcinoma cell lines. Also expressed on the surface of T-cells. Expression is lost when primary B-cells are induced to differentiate in antibody-forming cells. Extensively O-glycosylated. Disease susceptibility may be associated with variants affecting the gene represented in this entry. Belongs to the CD24 family.