108.3 Saturday, Jan. 7 The Role of Matrix Metalloproteinases in Immunity in the Caterpillar, Manduca sexta LINDNER, K.K.*; HARING, J.S.; RUBALCAVA, J.; NGUYEN, T.; GREENLEE, K.J.; North Dakota State University; North Dakota State University ; Northern Arizona University ; University of Maryland; North Dakota State University firstname.lastname@example.org
Insect immunity can be classified as humoral, such as the production of anti-microbial peptides, or cell-mediated. Cell-mediated immunity includes encapsulation, nodule formation, and phagocytosis. Because matrix metalloproteinase (MMP) mRNA is expressed in Drosophila hemocytes, we hypothesized that MMPs play a role in immunity. MMPs are a family of endoproteinases, with many roles across species, including immunological and developmental processes. However, the exact role of MMPs in immunity is still uncertain. To further understand the role of MMPs in cellular immunity, we used flow cytometry to assess phagocytosis by hemocytes, phase contrast microscopy to analyze hemocyte spreading, an anti-microbial assay to determine hemolymph cytotoxicity, and qPCR to determine MMP mRNA expression in the hemocytes and fat body 6 and 24 hours post E. coli infection. MMP mRNA expression was significantly up-regulated both 6 and 24 hours post-infection in both hemocytes and fat body, indicating a role of MMPs in both cell-mediated and humoral immunity. In addition, MMP protein expression was detected on hemocytes using immunohistochemistry. However, MMP inhibition did not affect hemolymph cytotoxicity or hemocyte phagocytosis and spreading. These data suggest that MMPs may be more involved in humoral immunity.