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The presence of glycosphingolipids in the metacestodes of the fox tapeworm, Tueniu crassiceps, has been established. The normal-phase TLC pattern of the neutral-fraction glycolipids revealed groups of bands corresponding to homologous components of increasing sugar chain length. The three simplest glycolipid components have been isolated and their chemical constitution determined as being of the neogala series: Galpl Cer, Galp6Galpl Cer and Galp6Galfl6Galbl Cer. The ceramide tetrasaccharide fraction has been found to consist of a mixture of neogalatetraosylceramide, as an elongation of the neogala series, Gal/36Galp6Galp6GalplCer and the component Gala4Galp6-GalB6GalplCer (both occurring in approximately equimolar proportions). The long-chain bases of the ceramide monogalactoside, digalactoside, trigalactoside and tetragalactosides contain, as well as small amounts of sphingosine, predominantly dihydrosphingosine/phytosphingosine in the approximate ratios 1.7: 1, 1.4: 1 , l : 1 and 2.3: 1, respectively. The major ceramide fatty acids have particularly long chains, with hexacosanoic and octacosanoic acids predominating. Upon reverse-phase TLC, the glycolipid components ceramide monogalactoside, digalactoside and trigalactoside were each separable into five component bands. Parent glycolipid components therefore show component band distributions comparable to one another in being governed by similar ceramide constitutions.As a possible reflection of their general relevance in biology, glycolipids are widely distributed in tissues of plants [l, 21, animals [3] An investigation of the glycolipids of multicellular parasites (protozoan parasites do not appear to contain major amounts of classical glycosphingolipids, i.e. compounds containing sugar linked to ceramide) was initiated in this laboratory, with the aim of increasing our knowledge of the diversity and distribution of their glycosphingolipids. It is hoped that this information will contribute to a better understanding of the putative roles of parasite glycosphingolipids in the maintenance of parasite integrity, in the mediation of parasite/ host interactions and in their significance in the host immune response. As a model, the metacestode stage of Taenia crassiceps has been chosen because of its relevance to other parasitic helminths that are pathogenic in humans, as well as for ease of propagation in laboratory mice [12]. Preliminary data have shown their neutral-fraction glycolipids to be antigenic, as evidenced by immunoreactivity (ELISA and HPTLC immunostaining) towards T. crassiceps metacestode-elicited infection serum, and, interestingly, against an affinitycolumn-isolated fraction [with parasite-derived ceramide trihexoside (CTH) as the ligand] [13].The results have shown that T. crassiceps metacestodes contain an array of glycolipids which can be separated by TLC into groups of chromatographic bands corresponding to homologous components of increasing sugar chain length. Isolation of ceramide monosaccharide, disaccharide, trisaccharide and tetrasa...

A preliminary characterization of the glycolipids of Litomosoides carinii macrofilariae, resolved according to their chromatographic, chemical and serological properties, has been performed. Emphasis has been placed on the neutral fraction glycolipids. These are separable on thinlayer chromatography into two groups of fast and slow migrating band components, that differ in their migration, differential chemical staining and serological traits, respectively. Serological analyses have been accomplished by thin-layer chromatography immunostaining and ELISA. Only components of the slow migrating band group react with infection serum from Litomosoides carinii-infected Mastomys coucha. Cross-reactivity experiments with homologous and heterologous infection sera of various helminthiases indicate that, epitopes bound to the neutral glycolipid fraction show structural similarity within the Nematoda, but not to the Cestoda or Trematoda. The dynamic development of specific Ig-, IgG- and IgM-anti-neutral glycolipid fraction antibody levels were correlated with the different progression of L. carinii and Brugia malayi infections in the multimammate rat, Mastomys coucha. The reduction in the dynamics of IgG- and IgM-antibody levels on chemotherapeutic treatment with the filaricides flubendazole and CGP 20376 has been related to their macrofilaricide-activity.

There is a general lack of basic information concerning one class of glycoconjugate, the glycolipids, from parasitic nematodes. As the prototype, the neutral glycolipid fraction derived from adult males of Ascaris suum was investigated as to its chromatographic, differential chemical staining, antigenic and chemical properties. The thin-layer chromatography-resolved neutral fraction glycolipids could be classified into components of fast and slow migrating band groups. Immunoreactivity was restricted to the latter as detected by IgG and IgM anti-neutral fraction glycolipid antibody levels in serial infection sera of mice. Similarities of chromatography, antigenicity and serological cross-reactivity have been extended to the neutral glycolipid fractions of other parasitic nematodes: Litomosoides carinii and Nippostrongylus brasiliensis. Chemical, differential chemical staining and enzymatic analyses identified the Ascaris suum antigenic, slow migrating band group of components as amphoteric glycosphingolipids, and not the originally hypothesized glycoglycerolipids or glycosylphosphatidylinositols, that contained typical neutral monosaccharide constituents and a zwitterionic phosphodiester linkage, most probably phosphocholine. Glycosphingolipid-immunoreactivity is eliminated on cleavage of the zwitterionic phosphodiester linkage by hydrofluoric acid treatment.

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