The pig is a powerful large animal model with a respiratory tract very similar to that of humans. I will discuss how best to deliver therapeutics and vaccines to the respiratory tract to harness mucosal immunity for protection against disease and to prevent transmission. We have evaluated the turnover and maintenance of immunological memory within the lung and demonstrated the role of T cells in protection against influenza. Mathematical modelling has been used to show that it is possible to predict immune response in the lung and assess protection by measuring immune parameters in the blood.