Insect Antimicrobial Peptides in Host Defense and Their Therapeutic Application

Antimicrobial peptides (AMPs) play a vital role in the innate immune system. They serve as the primary barrier against a range of infections. AMPs exhibit synergistic effects when used in conjunction with traditional antibiotics, thus offering the possibility of combination therapeutic approaches. Insects possess a remarkable level of resistance against infections caused by bacteria. Insect AMPs are positively charged and consist of fewer than 100 amino acids. The antibacterial activity of these insect peptides is achieved by disrupting the microbial membrane, thus preventing the development of drug resistance in microorganisms. The antibacterial properties of AMPs are now characterized by many membrane mechanisms, including the barrelstave-, toroidal pore-, carpet-, and disordered toroidal pore-model. The antibacterial activity of AMPs is influenced by factors such as the amount of positive charge, hydrophobic nature, and secondary structure of the peptide. The inadequate and excessive use of antibiotics has led to the emergence of antibiotic resistance, which is now recognized as a major worldwide public health concern by the World Health Organization. The goal of discovering alternative pharmaceuticals has proven to be an actual obstacle. Insects are the most extensive category of creatures within the animal world. Their humoral immune response involves the synthesis of AMPs that are then released into the insect’s hemolymph following a microbial infection. This chapter has mainly explored the immune responses of insects, with a specific focus on the features of AMPs, their mode of action, and their uses, particularly in the biomedical area.