The Biomphalaria glabrata embryonic (Bge) molluscan cell line: Establishment of an in vitro cellular model for the study of snail host-parasite interactions

Cell lines of invertebrates, especially those of arthropod origin, have pla yed crucial roles in addressing fundamental questions related to cell signa ling and differentiation, gene expression, cell-pathogen interactions, and the like. They also have been instrumental in the development of genetic tr ansformation systems and the development and testing of microbial insectici des. Recently, we have utilized a cell line originally derived from embryos of the freshwater snail Biomphalaria glabrata (Bge cell line; Hansen, 1976 a) to investigate the complex cellular, biochemical and molecular interacti ons between snails and their trematode parasites. Because this cell line wa s derived from B, glabrata, possesses a fibroblast-like appearance similar to circulating hemocytes, and shares in common several hemocyte functions ( substrate adhesion, phagocytosis, encapsulation, enzyme content), the Bge c ell line is proposed as a cellular model for B. glabrata hemocyte structure and function. In support of this proposal, a hemocyte beta-integrin cell a dhesion receptor homologue recently was identified and cloned based on info rmation from a previously acquired Bge cell beta integrin subunit cDNA sequ ence. As a general approach, it is anticipated that Bge cells can be evalua ted for genes associated with immune recognition/adhesion, and subsequently employed to generate molecular or immunological probes for use in hemocyte studies. Other applications of Bge cells to the study of parasite-snail ho st interactions include their use in the in vitro cultivation of intramollu scan stages of diverse trematode species, and in the development of genetic transformation systems for molluscan cells. Research in this latter area h as focused on the identification of suitable Bge cell promoters and testing their abilities to drive expression of reporter gene constructs. It is con cluded that the Bge cell line offers a diversity of valuable experimental a pproaches when applied to the study of molluscan cellular immune mechanisms or snail-trematode physiological interactions.