We generated a human TL1A knock-in (B-hTL1A mice) mouse model. Human TL1A gene expression in B-hTL1A mice was confirmed by RT-PCR. TL1A protein expression was not altered following TL1A humanization in B-hTL1A mice as shown by flow cytometry. Lastly, soluble human TL1A was detected in B-hTL1A mice by ELISA. Due to the purported role of TL1A in mucosal immunity, efforts to induce inflammatory bowel disease in this humanized model are currently underway.