Immunity in Invertebrates

Abstract

The science of immunology, which has recently undergone an explosive development, has dealt almost exclusively with the mechanisms of acquired immunity in vertebrate animals, especially in humans and other mammals. It must be realized that the great bulk of animal life consists of invertebrates. These must have effective mechanisms for dealing with invading parasites. In the light of evolutionary theory one would expect these mechanisms to bear some relation to those of vertebrates. Moreover, invertebrates serve as intermediate hosts for parasites of medical and economic importance; their relative susceptibility and resistance to these parasites are highly relevant to practical problems. The degree of susceptibility of mosquitoes to malarial parasites is genetically controlled. For certain mosquito-malarial parasite combinations it has been shown that a single gene is largely responsible for innate resistance, but the effector mechanisms for this are unknown. The same is true for innate susceptibility of mosquitoes to filarial larvae, and also for the susceptibility of snails to the developmental stages of schistosomes. If more were known regarding the detailed genetic basis of such susceptibility of vectors, it might be possible to develop practical applications for control of the parasites, a matter to which I will return in a later chapter.