My research has focused on the way mucosal surfaces respond to novel antigens associated with pathogens and with harmless, environmental materials like food, and how the mucosal immune system makes appropriate responses to each. My current work in this area is primarily concerned with the way commensal microbial ecosystems, in the intestine and at respiratory surfaces, control development of the immune system in neonates. Working primarily in pigs, I have also been involved in several studies using them as surgical and immunological models for humans, notably around corneal and laryngeal transplants. Current research includes the role of microbiomes in determining the function of the mucosal immune system, and the immune responses to respiratory viruses including influenza and SARS-CoV-2.