Annelid Humoral Immunity: Cell Lysis in Earthworms

Abstract

Earthworms and other organisms have deployed several strategies essential for maintaining and perpetuating species and one is the immune system that functions effectively against microbes. Effector activity against experimental antigens such as cancer cells is mediated by leukocytes and molecules that they synthesize and secrete (Cooper, et al., 1995; Cossarizza et al., 1995; 1996; Quaglino, et al., 1996; Cooper et al., 1992; 1999; Bilej et al., 1995; Kauschke et al., 1997). Current work emphasizes the capacity of coelomic fluid to effect lysis by means of a protein which has been referred to as Eiseniapore (Lange et al., 1997). Clearly the earthworm’s importance in understanding this aspect of invertebrate humoral immunity is significant as indicated by the recent increase in molecular studies relevant to lysis, (Lassegues et al., 1997; Milochau et al., 1997; Sekizawa, et al., 1997; Yamaji et al., 1998), its apparent regulation by serine proteases (Roch et al., 1997) and its possible relation to humoral agglutinins (H1, H2, H3), (Eue et al., 1997) and those antimicrobial peptides that are not hemolytic (Cho et al., 1998). These research groups propose the names fetidin, lysin, and now Eiseniapore, and perhaps perforin (Komiyama et al., 1997). From molecular analyses, these groups have cloned cDNAs which encode the cytolytic proteins and confirmed the activities of recombinant proteins. Certain common characteristics seem to be shared. As an example, their work reveals that the 40kDa fetidin has at least four isoforms with different isoelectric points and lysenin represents two isoforms of molecular masses of 41 and 42 kDa. This suggests that coelomic fluid of Eisenia fetida contains several sphingomyelin-binding cytolytic proteins with molecular masses around 40 kDa.