Alpha-defensins are small proteins that play a crucial role in the immune system. They are produced by certain white blood cells, particularly neutrophils and paneth cells, and help protect the body against infections by disrupting the membranes of bacteria, viruses, and fungi. These proteins are part of a larger group known as defensins, which are found in various organisms, including humans. Alpha-defensins are particularly important in the gut, where they help maintain a balanced microbiome and prevent harmful pathogens from causing disease.