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CUTICLIN GENES OF NEMATODESLEWIS E.*, SEBASTIANO M.*, NOLA M.*, ZEI F.*, LASSANDRO F.*, RISTORATORE F.,* CERMOLA M.*, FAVRE R.* AND BAZZICALUPO P.* KEYWORDS : parasitic nematodes, cuticle, cuticlin. dityrosine. cross-linking. SUMMARYTwo genes coding for cuticlin components of Caenorhabditis elegans have been cloned and their structure is described. Recombinant pro teins have been produced in E. coli and antibodies raised against them. Nucleic acid and specific antibodies are being used to isolate the homologues from the parasitic species Ascaris lumbricoides and Brugia pahangi.T he nematode cuticle protects the animal, serves as an exoskeleton and provides the surface over which inter actions with the external environment occur. In the case of parasitic nematodes the external environment is the host and, as such, antigens expressed on/in the cuticle are within reach of both the humoral and cellular components of the immune system. The cuticle is a layered structure, the components of which are classified according to their solubility : lipids, some proteins and other readily soluble, non-structural components are mostly localized on the sur face but are also distributed to a lesser extent throughout the lower layers of the cuticle ; the collagens make up the structural bulk of the cuticle, are coded for by a large and relatively well-characterized gene family, are not exposed on the cuticle surface and can be solubilized with SDS and mercaptoethanol ; and finally there is a highly cross-linked, insoluble and complex mixture of proteins present throu ghout the cuticle and known as the cuticlins. Up until now it has been virtually impossible to determine the roles and importance of the cuticlins because their insolubility does not allow either molecular or biochemical analysis of indivi dual proteins.