Grant: CIHR REDI Early Career Transition Award - Infectious Disease and Immune System

Humanity has constantly faced the challenge of overcoming infectious diseases and, despite massive advancements in medicine, they continue to represent threats to health. To fight diseases, we rely on a network of cells and organs that form the immune system. In mammals, the immune system is subdivided into two major components referred to as innate and adaptive immunity. Following infection with a pathogen, cells of the adaptive immune system display long-term functional changes and develop immunological memory. Such memory cells enable to the host to respond faster and stronger if the same pathogen is encountered again. For a long time, immunological memory was considered an exclusive hallmark of the adaptive immunity. Yet emerging evidence has shown that innate cells can also adapt their function after insults, thereby also showing the ability to be 'trained'. However, unlike adaptive memory, innate memory is not pathogen-specific. For example, some existing vaccines have beneficial effects against infections with pathogens that they were not originally intended to protect against. The underlying mechanisms involved in such innate memory is still elusive. The intestinal microbiota encompasses a community of bacteria that live in a mutually beneficial relationship with their host. The microbiota is known to regulate a number of processes, including the immune system. Successfully eliminating a pathogen requires continuous crosstalk between the microbiota and the host immune system. However, whether the gut microbiota can induce innate memory has not yet been studied. In this project, I will investigate whether intestinal microbiota can induce memory in cells residing within the gut called macrophages and the impact of such memory on intestinal health. This research will be critical for the design of new therapies and vaccines and allow us to harness the power of the gut microbiota to boost immune responses to infections or modulate inflammation in chronic diseases