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Journal NLM ID: 0370374
Publisher: Elsevier

Humoral immune responses were studied in 118 Venezuelan patients with either active mucocutaneous (MCL) or localized cutaneous leishmaniasis (LCL). Most patients had elevated antibody levels to the six promastigote oligosaccharide residues studied: galactosyl(α 1-2)galactose, galactosyl(α 1-3)galactose, galactosyl(α 1-6)galactose, galactosyl(α 1-3)mannose, galactofuranosyl(β1-3)mannose, and galactocerebroside. Significantly higher antibody levels were found in patients with MCL against galactosyl(α 1-3)galactose and Leishmania tropica glycoinositol phospholipid (GIPL)-1, GIPL-2, and GIPL-3 compared with patients with LCL. For both clinical forms of American cutaneous leishmaniasis (ACL), the most reactive antigen was galactosyl(α 1-3)galactose, with elevated levels found in 63% and 79% of MCL and LCL patients, respectively. In patients with MCL and LCL, no significant relationship was found between antibody levels against a given oligosaccharide residue and clinical parameters such as age, leishmanin diameter, number of skin lesions, or time of evolution. It is noteworthy that 33% and 15% of MCL and LCL patients, respectively, did not have elevated antibody levels against the six different oligosaccharide residues studied. This suggests the presence of a subpopulation of non-humoral immunoreactive ACL patients. The relationship between abnormal levels of oligosaccharide antibodies and the final outcome of the disease remains to be established.

NCBI PubMed ID: 1524141
Journal NLM ID: 0370507
Publisher: Northbrook, IL: American Society of Tropical Medicine and Hygiene
Institutions: Instituto de Biomedicina, Caracas, Venezuela

The major macromolecules on the surface of the parasitic protozoan Leishmania major appear to be down-regulated during transformation of the parasite from an insect-dwelling promastigote stage to an intracellular amastigote stage that invades mammalian macrophages. In contrast, the major parasite glycolipids, the glycoinositol phospholipids (GIPLs), are shown here to be expressed at near-constant levels in both developmental stages. The structures of the GIPLs from tissue-derived amastigotes have been determined by h.p.l.c. analysis of the deaminated and reduced glycan head groups, and by chemical and enzymic sequencing. The deduced structures appear to form a complete biosynthetic series, ranging from Man α 1-4GlcN-phosphatidylinositol (PI) to Gal α1-3 Galf β1-3 Man α1-3 Man α1-4 GlcN-PI (GIPL-2). A small proportion of GIPL-2 was further extended by addition of a Gal residue in either α 1-6 or β 1-3 linkage. From g.c.-m.s. analysis and mild base treatment, all the GIPLs were shown to contain either alkylacylglycerol or lyso-alkylglycerol lipid moieties, where the alkyl chains were predominantly C18:0, with lower levels of C20:0, C22:0 and C24:0. L. major amastigotes also contained at least two PI-specific phospholipase C-resistant glycolipids which are absent from promastigotes. These neutral glycolipids were resistant to both mild acid and mild base hydrolysis, contained terminal β-Gal residues and were not lost during extensive purification of amastigotes from host cell membranes. It is likely that these glycolipids are glycosphingolipids acquired from the mammalian host. The GIPL profile of L. major amastigotes is compared with the profiles found in L. major promastigotes and L. donovani amastigotes.

NCBI PubMed ID: 8240257
Journal NLM ID: 2984726R
Publisher: London, UK : Published by Portland Press on behalf of the Biochemical Society
Institutions: Department of Biochemistry, University of Dundee, UK.

Galactofuranose has been characterized in glycoinositolphospholipid (GIPL) anchor-like structures having a glycerolipid or a ceramide, as in lipopeptidophosphoglycan (LPPG) of Trypanosoma cruzi, in the oligosaccharide core of lipopeptidophosphoglycan (LPG) of Leishmania species, and also modifying high-mannose chains of trypanosomatid glycoproteins. Galactofuranose is usually present linked β1→3 to Man, either as a terminal non-reducing unit, like in LPPG, or in the middle of the oligosaccharide core, as in LPG. The presence in protozoan parasites of galactose in the furanose configuration is a feature which deserves further attention since the mammalian hosts do not appear to produce glycoconjugates containing this structural unit. For that reason, hosts produce antibodies against galactofuranose, which may turn out to be important in understanding the pathogenesis and in the development of diagnostic methods. The metabolic pathways involved in the attachment to or removal of galactofuranose from glycoconjugates have not yet been elucidated. This is an area of incipient research, but of growing importance, since it will foster the design of inhibitors which may prove to be useful for the treatment of disease.

NCBI PubMed ID: 8563141
Journal NLM ID: 9104124
Publisher: IRL Press at Oxford University Press
Institutions: Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina