Professor Lehner is a Clinician Scientist and Immunobiologist at the University of Cambridge. He obtained his medical degree from University College London and PhD from the University of Cardiff. Paul is distinguished for his work on the cell biology of immune and viral evasion pathways. Prominent among these are his discoveries of how the vertebrate genome is defended from invasion by silencing RNA-derived retroelements, such as retroviruses and LINE-1 retroelements, and his application of unbiased quantitative proteomics for understanding how clinically important human viruses remodel the infected host cell. His discovery of the ‘HUSH’ (Human Silencing Hub) epigenetic silencing complex explains how the genome distinguishes newly integrated genetic material from endogenous genes through recognition of intronless DNA. This work uncovered an unanticipated, innate immune surveillance system that discriminates ‘self’ from ‘non-self’ genomic DNA and defends our genome against the reverse flow of genetic information (RNA to DNA), paving the way to novel applications in medicine and biotechnology.