Immunity
Antiobiotics from the fruit fly?
Antimicrobial peptides – agents of non-specific immunity – can also target certain bacteria and fungi.
Glowing bacteria inside the fruit fly testify to its damaged immune system. | Image: zVg
Discovered in the 1980s in insects, antimicrobial peptides are key actors in innate or non-specific immunity, a type of immunity present in all living organisms and which acts as a kind of first-line defence. Today, the teamwork led by Bruno Lemaitre, an immunologist at EPFL, shows a new complexity and an unsuspected specificity of these peptides when confronting bacteria and fungi.
Unlike adaptive immunity – found in vertebrates and made up of specific antibodies, lymphocytes and immune memory – innate immunity seemed to act regardless of the type of disease to be fought. “Antimicrobial peptides are a universal defence mechanism, because thanks to their positive charge they create pores in negatively charged bacteria”, says Lemaitre. “However, we have shown in fruit flies that some of these peptides have a specific mode of action. They behave like projectiles capable of targeting certain bacteria and fungi in particular”.
“These peptides are proving increasingly interesting to study”, says Lemaitre. “By understanding how they work and how they are regulated, we can better understand the diseases that affect insects. As these peptides are also present in humans, we can also envisage making progress towards the development of new types of antibiotics, discovering more about their anti-carcinogenic properties and understanding their potential role in neurodegenerative diseases”.
