The immune system can broadly be divided into innate and adaptive ‘arms’. The innate immune system detects pathogens and abnormal cells – such as those infected with viruses or cancer cells - and mounts a fast, inflammatory response. The adaptive immune system responds to molecular cues and ‘danger signals’ from the innate immune system before mounting a specific and long-lived response against the pathogen at hand. Gamma-delta T cells are a type of immune cell found in areas such as the gut and skin. Due to their ability to perform fast, innate-like tissue surveillance while having some – if limited – specificity to what they can detect, gamma-delta T cells are thought to sit somewhere in the middle of these two arms.
A study published recently in Nature Immunology has unveiled an exciting function of gamma-delta T cells that challenges the notion of the immune system existing in two separate arms. Research teams at the Francis Crick Institute and King’s College London, from BSI member and study leader Professor Adrian Hayday, showed that gamma-delta T cells can perform both innate and adaptive functions by using a single molecule found on their surface. Using this molecule, gamma-delta T cells use a two-pronged approach to check a cell’s abnormality – an innate function – and then mount a specific attack, as seen in the adaptive response, without having to rely on authorisation from other immune signals.
Describing the findings, Professor Hayday said, “These maverick immune cells act as judge, jury and executioner, identifying and killing potentially dangerous cells in the body. This discovery was a huge surprise. It fundamentally changes our understanding of how the immune system makes critical judgment calls about when to act and when to hold back. This could open up exciting possibilities for treating disease.”
provided: by Francis Crick Institute