Il4 Conditional Knockout mouse models

Il4 is the mouse ortholog of human IL4 and encodes the initiating type 2 cytokine, signaling through the type I receptor of IL-4Ralpha with the common gamma chain on lymphocytes and the type II receptor of IL-4Ralpha with IL-13Ralpha1 on myeloid and stromal cells, converging on STAT6 to induce GATA3, immunoglobulin E class switching, and alternative macrophage activation. Its locus lies adjacent to Il13 and Il5 under shared conserved noncoding regulatory elements, so cassette placement can perturb neighbors and generate phenotypes mistakenly attributed to interleukin 4 alone. Because interleukin 4 and interleukin 13 share IL-4Ralpha and STAT6, single nulls give partial results and compound Il4 with Il13 or Il4ra deletion is required for full type 2 collapse. Bicistronic fluorophore reporter knockins mark competent producers without perturbation, while humanization is the appropriate allele for dupilumab-class receptor blockade, and conditional deletion with Cd4-Cre or ILC2 restricted drivers assigns the cellular source.

A floxed Il4 allele paired with Cre gives spatial control that whole body knockouts cannot offer. People use it to separate developmental roles from adult homeostasis, to model somatic mutations, and to match disease that begins in one organ.