Rabbit anti Mouse Interleukin-4 antibody recognizes mouse interleukin-4 (IL-4), also known as B-cell stimulatory factor 1, a 120 amino acid pleiotropic cytokine cleaved from a 140 amino acid precursor which interacts with multiple cell lineages, including T cells, fibroblasts and macrophages (Crawford et al. 1987).Interleukin-4 is one of the most important factors involved in B cell IgG1 and IgE class switching (Winter et al. 1987). IL-4 acts as a regulator of low affinity Fc receptor for IgE (CD23) expression on both lymphocytes and monocytes (Miyajima et al. 1991, Hudak et al. 1987). IL-4 acts through binding to it's cognate receptor CD124, a receptor which also binds the related cytokine IL-13.Interleukin -4 plays an important role in the alternative activation of murine macrophages as indicated by the ability to potently up-regulate the expression and activity of CD206, the macrophage mannose receptor (Stein et al. 1992).