This is a humanized IgG4 antibody using the same sequences as the therapeutic antibody lebrikizumab. It blocks interleukin 13 (IL13), a cytokine (cell-signalling protein) that is produced by a type of white blood cell called Th2 cells. IL13 is thought to induce the expression of another signalling protein, periostin, by epithelial cells of the bronchi. Periostin in turn seems to partake in a number of asthma related problems, such as bronchial hyperresponsiveness, inflammation, and activation and proliferation of airway fibroblasts, which are involved in airway remodelling. Lebrikizumab binds IL13 with high affinity to specifically prevent the formation of the IL13Rα1/IL4Rα heterodimer complex and subsequent signaling, thereby inhibiting the biological effects of IL13 in a targeted and efficient fashion.