Insects may have complex immunity

Insects may possess a hitherto unsuspected molecular complexity in their immune system, comparable to the antibody system of mammals, scientists report online this week in Science.

"The number of immune receptors might go from a couple of dozen up to thousands in insects. The complexity there might have really been underestimated," senior author Dietmar Schmucker, of Harvard Medical School in Boston, told The Scientist.

In 2000, Schmucker and colleagues discovered that the Down syndrome cell adhesion molecule gene (Dscam) could, through alternative splicing, generate more than 38,000 proteins in Drosophila. The immunoglobulin super family receptor appeared to guide neuronal wiring.

In the current study, the researchers investigated whether Dscam played a role in immune response. Using reverse transcriptase polymerase chain reaction (RT-PCR), they found Dscam expression in Drosophila fat body cells, which secrete antimicrobial peptides, and hemocytes, which are involved in phagocytosis. Using antibodies against extracellular domains of Dscam, they ...