Lucas Horn, Biology
“Assaying Phagocytic Ability of Adult Blood Cells In Drosophila melanogaster”
Faculty Mentors: Dr. Jeff Leips and Dr. Michelle
Expected Graduation Date: 2011
While physiological changes in the immune system with age are well-known, very little is known about the genetic basis of such changes. First, I will test the hypothesis that genetically based differences in the ability to clear infection with age results from differences among genotypes in the ability of blood cells to phagocytise (engulf) bacteria. The second aim tests the hypothesis that the gene lola (which also has a homologous gene in humans), influences age-specific phagocytic ability of blood cells. This project will contribute to our understanding of the genetic basis of immunosenescence. The immune response of Drosophila has two main components, clearance of bacteria by phagocytic blood cells and production of antimicrobial proteins. Until now, no protocol was available to reliably and quantitatively measure the phagocytic ability of adult blood cells in Drosophila. I have modified a protocol designed for use with fly larvae to measure the phagocytic ability of adult blood cells. This procedure will allow me to determine if differences in the age-specific phagocytic ability of blood cells among the lines contributes to the differences in clearance ability among lines. Extension of this procedure to larger populations will allow us to map genes across the genome affecting this trait. I focus on phagocytosis because phagocytic ability declines with age in many organisms. Phagocytosis may also be more important for clearing infection than production of antimicrobial peptides. A microarray study in our laboratory identified a candidate gene called lola who expression is potentially involved in the ability to clear infection at different ages. Mutations in this gene affect the phagocytic ability of cells in cell culture, making lola an ideal candidate for testing its effect on phagocytic ability among our lines.