COOPER, E L: Comparative Immunology

Comparative immunology, derived from zoology and immunology, examines immune systems during evolution. Invertebrate immunology, a branch begins analyses even with protozoans, capable of more phagocytosis! Now we know that they possess molecules with conserved sequences found in multicellular species (lysins in amoebas and interleukins in ciliates). Phagocytosis in invertebrates that paved the way for reconciling controversy between humoral immunity vs. cellular immunity. Immunologists discovered antibodies in vertebrates and different but equally efficient molecules that mediate humoral immunity in invertebrates (eg. lysins, agglutinins, and opsonins). Cellular immunity, e.g. graft rejection, seems to share similar characteristics in both animal groups. The immune system is divided into two major camps adaptive (induced, specific, clonal, anticipatory) and innate (natural, non-specific, non-clonal, non-anticipatory). Invertebrates possess cellular and humoral responses that are mostly innate, whereas both the innate and the adaptive are associated with vertebrates. Comparative immunology promises continued: 1. unification of interrelated mechanisms/concepts based upon firm molecular information, (e.g. signal transduction; homology vs. analogy; convergent vs. divergent evolution); 2. unification of the three regulatory systems, immune, nervous, and endocrine; 3. understanding of immunity in models of economic importance (e.g. pests, parasites, disease vectors, and food) that will be useful as inexpensive, non-controversial sources of information; 4. analyses of relation between biospheric inhabitants, environment and seasons; 5. development of “new wave antibiotics” and therapeutic components based upon naturally occurring antimicrobial molecules.