PGLYRP1 and Immunodeficiency: The second NF-κB pathway that regulates AMP expression in Drosophila is immune deficiency (Imd), which is induced by many Gram-negative bacteria through the transmembrane PGRP-LC and the intracellular PGRP-LE peptidoglycan recognition proteins (PGRPs) [7,8] (Figure 1).