STUDIES ON THE IMMUNOPARASITOLOGY OF EASTERN PAINTED TURTLES (CHRYSEMYS PICTA PICTA) AND SNAPPING TURTLES (CHELYDRA SERPENTINA) EXPOSED TO SPIRORCHID BLOOD FLUKES (SPIRORCHIS SCRIPTA) (REPTILE)
Humoral and cellular immune responses of painted turtles (Chrysemys picta picta) and snapping turtles (Chelydra serpentina) to antigens from the eggs of the trematode Spirorchis scripta were monitored. Trematode eggs were removed from painted turtle lungs, pulverized, and injected into known parasite-free snapping turtles. Injected snapping turtles had greater numbers of eosinophilic granulocytic cells (EGC) in their spleens, where crushed egg particles may have been sequestered, than did naturally infected painted turtles with old spleen lesions, suggesting that EGC-type cells are early participants in reptilian anti-helminth defenses. Snapping turtles also produced specific antibody to spirorchid eggs observable in agglutination, gel precipitation, and ova precipitin tests. The immune response intensities were dependent on holding tank temperature and frequency of antigenic stimulation.^ Rhode Island painted turtles had high incidence of spirorchidiasis (81.82%). Lung tissue was the most heavily burdened with trematode eggs and was the most reliable indicator of trematode infection. Infected painted turtles had significantly higher proportions of gamma globulin fraction in sera separated by electrophoresis than did noninfected turtles, suggesting that antibody to spirorchids was being produced. No significant differences were found between agglutination, precipitation, and ova precipitin reactions for infected and noninfected painted turtles. This suggests that noninfected turtles were previously exposed to spirorchid antigen and were maintaining levels of antibody, perhaps in anticipation of future infection. Alternatively, spirorchid antigen in turtles may have the properties of Forrsman antigen (common to many animal tissues) in mammals. Infected painted turtles were heavily burdened with spirorchid eggs in lung and spleen; otherwise they appeared healthy and reproductively active. Many trematode eggs seen microscopically in spleen, kidney, liver, pancreas, and enteric organs were being destroyed by host cellular responses. These findings indicate painted turtles are adapted to defending against schistosomes and are able to survive infections which are seriously debilitating to mammals, especially primates. Whether or not infections in mammals and reptiles can be equated has yet to be proven and seems rhetorical. Since similar cells participate in parasitic infections of both animal classes, the proposal is made that infectious responses are similar within phylogenetic constraints. ^
Health Sciences, Immunology
DAVID MARRS HUDSON,
"STUDIES ON THE IMMUNOPARASITOLOGY OF EASTERN PAINTED TURTLES (CHRYSEMYS PICTA PICTA) AND SNAPPING TURTLES (CHELYDRA SERPENTINA) EXPOSED TO SPIRORCHID BLOOD FLUKES (SPIRORCHIS SCRIPTA) (REPTILE)"
Dissertations and Master's Theses (Campus Access).