Immune–bacteriophage interactions in inflammatory bowel diseases

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are influenced by the bacterial and fungal organisms found within the intestine. However, the intestine is also home to a vast number of viral particles, with most of them being viruses that infect prokaryotes, called bacteriophages. While use of bacteriophages to specifically target pathogenic bacterial species involved in IBD is currently under investigation, recent studies have also highlighted that these viral particles can impact the mammalian immune system. IBD is a chronic multi-factorial inflammatory condition with unknown etiology. This review will highlight the current investigations that have revealed that bacteriophage-mammalian immune cell interactions can influence disease processes beyond their known role for infecting bacteria, which might identify novel ways to treat or diagnose IBD.