The human body is colonised by a diverse collective of microorganisms, including bacteria, fungi, protozoa and viruses, with the largest microbial community found within the gut. It is well established that our gut microbial flora has co-evolved with us, forming ‘symbiotic relationships’ with our bodies that are largely responsible for our overall well being. These gut-microbe symbioses impart additional beneficial functions associated with nutrient metabolism, regulation of our immune system and protection against pathogens. The smallest entity of our microbiome are the bacterial viruses. Bacteriophages, or phages for short, exert significant selective pressure on their bacterial hosts, undoubtedly influencing the human microbiome and its impact on our health and well-being. Phages colonise all niches of the body, including the skin, oral cavity, lungs, gut, and urinary tract. As such our bodies are frequently and continuously expo

ed to diverse collections of phages. Despite the prevalence of phages throughout our bodies, the extent of their interactions with human cells, organs, and immune system is still largely unknown. Phages physically interact with our mucosal surfaces, are capable of bypassing and entering epithelial cell layers, disseminate throughout the body and may manipulate our immune system. Here, I will discuss our lab's research investigating the diverse ways in which phages interact and influence the human body and propose a novel concept of tripartite symbioses between phages, their bacterial hosts, and the human gut epithelium.