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Date of Award
Bachelor of Science (BS)
Department of Biology
Malaria is a blood-borne disease caused by protozoans of the genus Plasmodium. Currently, 300-500 million cases are reported each year and 1.3 million deaths occur world-wide, with the majority taking place in developing nations. Four major species of Plasmodium cause disease in humans, the most wide-spread of them being Plasmodium falciparum. Typical symptoms of malaria include fever, lethargy, splenomegaly, and anemia, and in severe cases, neurological symptoms may arise. Interleukin-3 (IL-3), a cytokine released primarily by activated T-cells and mast cells, is known for its hematopoietic growth functions. It has also been shown to play a protective role in nematode infections and in promoting delayed-type contact hypersensitivity responses. In this study, we investigated the extent to which IL-3 plays a role in the host response to Plasmodium infections. We induced a blood-stage malaria infection in wild-type (WT) and IL-3-deficient (IL-3 -/-) mice using P. berghei ANKA, a lethal strain of Plasmodium that infects rodents. We show that infected female IL-3 -/- mice, but not male mice, presented with lower numbers of circulating parasitized red blood cells, were more anemic, and had increased splenomegaly compared to corresponding WT mice. However, there was no difference in the survival rate between infected male or female mice of either genotype. Together these data indicate that IL-3 might act to suppress protective immune responses to P. berghei ANKA in female mice, but these actions were not enough to prolong survival. Our findings that gender influences the disease indicators likely suggest hormonal and immunological differences in the sexes. These findings are in contrast to similar studies by our laboratory using P. berghei NK65-infected IL-3 -/- and WT mice in which it was shown that IL-3 plays a critical role in suppressing protective immunity in both male and female mice, and prolongs survival in male mice. We believe that the studies presented here, together with those reported for P. berghei NK65, will help to eventually elucidate the relative contribution of IL-3 in the resulting morbidity and mortality associated with both rodent and human malaria.
Sheikh, Abdalla, "Role of interleukin-3 in blood-stage malaria infection caused by Plasmodium berghei ANKA" (2014). Senior Honors Projects, 2010-current. 477.