Defining the transcriptional signature of healing and non-healing lesions during murine cutaneous leishmaniasis

Leishmaniasis is a group of diseases caused by parasites of the genus Leishmania that affects millions of people worldwide. The disease outcome is determined by both the parasite species and the host's immune response. Leishmania major infection causes a localized cutaneous lesion in patients and has been widely used to study the development of T cell responses in mice. L. major infected C57BL/6 mice are resistant to infection due to the development of Th1 responses, whereas BALB/c mice develop a Th2 response resulting in disease susceptibility and failure to control parasite replication. However, these disparate host phenotypes are not observed with all Leishmania species. For example, during L. braziliensis infection both BALB/c and C57BL/6 mice are resistant. In order to better understand the host genetic basis underlying disease susceptibility in vivo, we performed a whole genome transcriptional analysis from skin lesions of BALB/c and C57BL/6 mice infected intradermally for 4 weeks with either L. braziliensis or L. major. twenty-four ear samples were recovered from either naïve mice or mice infected with Leishmania. For each infection, 4-5 mice were processed and the entire infected ear was recovered for RNA. Three naïve mice for each strain (Balb/c and C57BL/6) served as controls.