Dr Haagsman is a biochemist whose research focus has changed several times over the years. Since 1983 he has been interested in barrier functions of (mucosal) surfaces, especially in the lungs. During the past fifteen years his main research line was in the field of Antimicrobial Peptides (AMPs) / Host Defence Peptides (HDPs). Dr Haagsman's research projects are aimed to learn more about the natural defense systems of animals and to use this knowledge to fight infections in animals and humans. His work is a prime example of One Health/One Medicine research and translates results from studies about properties and roles of host defense molecules into new concepts of prophylactic and therapeutic anti-infectives (including vaccines).