Anti-IL-4 antibodies enable researchers to detect and measure the IL-4 antigen in biological samples. This target is a reported synonym of the IL4 gene, which encodes interleukin 4. This protein is known to function in B cell differentiation and cholesterol metabolism and homeostasis, among other biological roles. The human version of IL-4 has a canonical amino acid length of 153 residues and a protein mass of 17.5 kilodaltons, although 2 isoforms have been identified. It is reported to be a secreted protein. Other names for this target antigen include BCGF-1, BCGF1, and BSF-1.