METHODS: To investigate the contribution of the LALA mutation in the Fc portion to IL-23 neutralization in vivo, we administered anti-IL-23 antibodies bearing either WT or LALA-modified Fc portions to Ig-competent (Il10−/−) and Ig-deficient (Rag2−/−) preclinical colitis mouse models. This evidence concerns the gene IL10 and colitis.