Over the last few years, insights into the antimicrobial defenses of the fruit fly Drosophila melanogaster have revealed remarkable parallels between insect and mammalian innate immunity (1). Relatively little is known about the immune responses of C. elegans . In Drosophila , an infection provokes the rapid sysnthesis of powerful antimicrobial peptides and opsonising proteins (2). While seven distinct anti-microbial peptides have been identified in flies, thus far, only two have been characterised from C. elegans , encoded by
abf-1 and
abf-2 on C50F2 (3; see also 4). Searching for conserved peptide motifs has yielded two further family members,
abf-3 and
abf-4 , (on F54B8 and Y38H6C, respectively) the study of which we are undertaking. Further, we are using MALDI-TOF mass spectrometry to investigate whether other antimicrobial peptides are induced upon infection of C. elegans . In Drosophila , the expression of anti-fungal peptides is controlled by the Toll pathway (5). A search of the genome reveals that C. elegans possesses structural homologues of most of the components of this signalling cascade (for Toll, pelle, tube, cactus, on cosmids C07F11, K09B11, F45G2 and C04F12, respectively). As a first step, we are using Northern analysis to determine whether this putative pathway is implicated in worm defense mechanisms. The results of these investigations will be presented. 1. Medzhitov and Janeway, 1998, Curr Opin Immunol, 10, 12-5 2. Hoffmann and Reichhart, 1997, Trends in Cell Biology, 7, 309-316 3. Kato, 1997, International Worm Meeting abstract 296 4. Kato and Komatsu, 1996, J. Biol. Chem., 271, 30493-30498 5. Lemaitre et al., 1996, Cell, 86, 973-983