© 1989 by The Society for Integrative and Comparative Biology
Immunoparasitology in Avian Species1
U.S. Department of Agriculture, Agriculture Research Service, Protozoan Diseases Laboratory, Animal Parasitology Institute Beltsville, Maryland 20705
There has been no work on the immunological response of birds to helminth infections since the late 1960s, an area of investigation that has been too long ignored. Similarly, studies of arthropod-mediated responses in birds are lacking except for a few scattered investigations. Recently, a serum antibody response has been seen against one arthropod, the northern fowl mite. The appearance of antibodies recognizing an 8–10 kilodalton mite antigen seems to correlate with a reduction in the mite population on infested chickens. Most of the studies on parasite immunity in avian species have centered on the economically important Eimeria species, protozoan parasites that infect the intestine of chickens and turkeys. These investigations encompass wide areas of interest including the effect of immunity on parasite invasion, development of T-cell proliferation assays and T-cell clones, inhibition of parasite penetration and development by hybridoma antibody treatment, production of genetically engineered Eimeria antigens used in bird immunization studies, and studies using inbred or congenic lines of birds to determine what effect the major histocompatibility complex has on parasite immunity. From these efforts it has been learned that not only is the immunity species-specific, but also depending on where in the intestine the parasite invades, penetration is either not affected or inhibited by as much as 50%. The T-cell proliferation assays suggest that this specificity may be due to a species-specific T-cell response. Immunization studies using a genetically engineered antigen have indicated that at least partial protection against one species of Eimeria is possible. Studies done with the inbred congenic lines of birds have shown that the genetic makeup of the bird is important in how it responds to either a natural infection or to immunization with a genetically engineered antigen. Clearly, these results show not only the complexity of the bird response to parasite infection, but also the amount of work still undone.