Defensins are small, cationic peptides that play a crucial role in the innate immune response. They are classified into two main types: alpha defensins and beta defensins. The primary function of both types is to directly target and disrupt microbial membranes.
Alpha defensins are primarily produced by neutrophils and certain epithelial cells, while beta defensins are mainly expressed in epithelial tissues throughout the body. When these defensins encounter pathogens such as bacteria, fungi, and even viruses, they can insert themselves into the microbial membranes, leading to membrane destabilization and ultimately causing cell lysis or death. This mechanism is essential for controlling infections and serves as a first line of defense against a wide range of microorganisms.
The other choices incorrectly describe the types or functions of defensins, as they either misidentify the classifications or indicate functions that do not align with the known roles of defensins in microbial membrane disruption.