Lipids shed into the culture medium by trypomastigotes of Trypanosoma cruzi

Trypomastigote forms of Trypanosoma cruzi were metabolically labeled with [14C]-ethanolamine and [3H]-palmitic acid. Lipids shed to the culture medium were analyzed and compared with the parasite components. Phosphatidylcholine and lysophosphatidylcholine accounted for 53 per cent of the total incorporated precursor. Interestingly, phosphatidylethanolamine and its lyso derivative lysophosphatidylethanolamine, although present in significant amounts in the parasites, could not be detected in the shed material. Shed lipids were highly enriched in the desaturated fatty acids C16:1 and C18:1 when compared to the total fatty acid pool isolated from the parasites.

Different pattern of glycoproteins with unusual O-linked oligosaccharides in two strains of Trypanosoma cruzi epimastigotes

The glycoconjugate profiles of epimastigotes of the Y strain and of two stocks of the tulahuen strain which differ in their infectivity have been compared. The surface location of the glycoconjugates was evidenced by labelling with glactose oxidase/NaB3H4. Fluorography of SDS-polyacrylamide gel electrophoresis showed a different pattern in the glycoprotein range for both strains and also for two lines (T0 and T2) of the Tulahuen strain. While T0 showed only one glycoprotein with Mr 45 kDa, T2 revealed three glycoproteins in the range of 25-57 kDa. Two fast components, corresponding to glycolipids were also shown. The glycoproteins were isolated with 44 percent phenol and they were purified from the aqueous phase. Alkaline borohydride treatment of the labelled glycoproteins under the conditions of beta-elimination released strongly labelled O-glycosidically linked oligosaccharides. These O-linked glycans are not of the usual type found in glycoproteins. N-acetylgalactosamine which links O-glycans to the protein in the known mucin type glycoproteins has not been detected in the T. cruzi glycoproteins (1).

Producción de interleuquina 1 durante el crecimiento tumoral / Production of interleukin 1 during tumor development

La producción de IL-1 por células esplénicas mononucleares adherentes (CMA) de ratones BALB/c inoculados con Sarcoma 180(S180) fue estudiada como uno de los posibles mecanismos responsables de la inmunosupresión observada durante el crecimiento tumoral. Como agentes estimulantes se utilizó un polisacárido químicamente definido, PCj3, y un lipopolisacárido de E. coli (LPS). La actividad de IL-1 se valoró en base al efecto estimulante de los sobrenadantes de cultivos en CMA sobre la respuesta proliferativa de timocitos murinos frente a la fitohemaglutina (PHA). Ambos esdtimulantes indujeron niveles comparables de IL-1 tanto en ratones normales como en portadores de S180 de 10 días. A los 20 y 30 días de desarrollo tumoral, las CMA disminuyeron significativamente la producción de IL-1 en respuesta a ambos estimulantes. Esos resultados permiten suponer que la inmunosupresión observada en los ultimos estadíos del crecimientos tumoral podría ser consecuencia de la inhibición de la producción de IL-1