2025, Vol. 6, Issue 2, Part D

Invertebrates have an innate immune system, similar to vertebrates, which serves as their primary defense against disease-causing agents, while vertebrates also have an adaptive immune system. The major invertebrate classes comprising arthropods, molluscs, annelids, and echinoderms were the focus of this investigation. This was because they have very diverse and evolutionarily conserved innate immune systems. Pattern recognition receptors (PRRs), antimicrobial peptides (AMPs), and immune cells like hemocytes that aid in pathogen recognition, immune response activation, and phagocytosis are among the immune system components mentioned in the study. This review also shows the latest progress in comparative immunology that uncovers the molecular diversity and the intricacy of the invertebrate immune systems. The article explores the debate over "immune memory" in invertebrate organisms, highlighting concepts of immune priming and trained immunity, suggesting memory may not be exclusive to adaptive immunity. The results obtained point out that innate immune system in invertebrates is not only sufficient as a first line of defence against pathogens but also has major functions in inflammation regulation as well as tissue repair. By comparing the different immune systems, it was observed that the work is an important step in understating the evolutionary roots of innate immunity and the consequences this has for the study of immune system evolution in other multicellular organisms. Also, this study examines the exploration of research beyond the present knowledge frontier; some of these possibilities include, for instance, the role of immune mechanisms of invertebrates in the development of pest control and aquaculture industry.