Recombinant Human IL4 protein

Interleukin-4 (IL-4) is a pleiotropic cytokine critical in regulating immune responses, particularly those associated with type 2 immunity. First identified in the 1980s, IL-4 is primarily secreted by activated T helper 2 (Th2) cells, mast cells, and basophils. It plays a central role in promoting B cell differentiation, antibody class-switching to IgE and IgG, and the activation of macrophages toward an anti-inflammatory phenotype. Additionally, IL-4 drives the differentiation of naïve T cells into Th2 cells, creating a feedback loop that amplifies type 2 immune responses. This cytokine is also implicated in allergic inflammation, host defense against helminth infections, and tissue repair processes.

Recombinant IL-4 protein, produced via genetic engineering in systems such as *E. coli* or mammalian cell cultures, retains the biological activity of native IL-4 while offering high purity and consistency. Its production enables precise study of IL-4 signaling mechanisms and therapeutic applications. Structurally, IL-4 is a four-α-helix bundle protein that binds to a heterodimeric receptor complex comprising the IL-4 receptor α (IL-4Rα) subunit and either the common γ-chain (γc) or IL-13 receptor α1 (IL-13Rα1), triggering JAK-STAT signaling pathways.

In research, recombinant IL-4 is widely used to model Th2-polarized immune responses, investigate allergic diseases, and explore its dual roles in cancer—both as a tumor-promoting agent and a modulator of antitumor immunity. Therapeutically, IL-4-based strategies are being explored for immune disorders and cancers, though challenges remain due to its context-dependent functions. For instance, IL-4 receptor-targeted therapies aim to block pathogenic signaling in allergies, while engineered IL-4 toxins are studied for selective tumor cell targeting. Despite its complex biology, recombinant IL-4 remains a vital tool for dissecting immune regulation and developing targeted immunotherapies.