Watson, F.L., Puttmann-Holgado, R., Thomas, F., Lamar, D.L., Hughes, M., Kondo, M., Rebel, V.I., Schmucker, D. (2005). Extensive diversity of Ig-superfamily proteins in the immune system of insects.  Science 309(5742): 1874--1878.

FBrf0188335

Research paper

The extensive somatic diversification of immune receptors is a hallmark of higher vertebrates. However, whether molecular diversity contributes to immune protection in invertebrates is unknown. We present evidence that Drosophila immune-competent cells have the potential to express more than 18,000 isoforms of the immunoglobulin (Ig)-superfamily receptor Down syndrome cell adhesion molecule (Dscam). Secreted protein isoforms of Dscam were detected in the hemolymph, and hemocyte-specific loss of Dscam impaired the efficiency of phagocytic uptake of bacteria, possibly due to reduced bacterial binding. Importantly, the molecular diversity of Dscam transcripts generated through a mechanism of alternative splicing is highly conserved across major insect orders, suggesting an unsuspected molecular complexity of the innate immune system of insects.