Abstract:
The effects of leishmanial infection on various parameters of a susceptible strain of mice, Balb/c, were studied. Specifically, we were interested in the change in percent of Ia positive peritoneal macrophages as the disease progressed. Typically, in healthy animals, peritoneal macrophages express low percentages of Ia. Previous studies have shown, however, that in an autoimmune disease, such as found in MRL-lpr mice and infections such as Listeria monocytogenes, there is a dramatic increase in Ia expression on macrophages. In our work, Balb/c mice were injected in the footpad with an inoculum of Leishmania major and the Ia expression on peritoneal macrophages was followed, along with several other disease parameters, throughout the course of the infection. These parameters included foot pad size, spleen weight, isolation of L. major from spleen culture, and regional lymph node weight. Results of this investigation indicate that: expression of Ia does greatly increase over the course of the infection and occurs prior to splenomegaly and significant lymphoproliferation, which are characteristic manifestations of the infection. This suggests that the Ia expression may have some, as yet unknown, influence on immune regulation and the failure of this mouse strain to develop a protective immunity to the parasite.
