Nadia Nogueira

Characterization of a candidate gene for GP72, an insect stage-specific antigen ofTrypanosoma cruzi

The Trypanosoma cruzi insect stage-specific antigen GP72 was purified from epimastigotes and the amino acid sequences of peptide fragments determined. Oligonucleotides derived from these data were used to amplify and clone a cDNA sequence, which was used to isolate a full-length gene. All the sequenced peptides were encoded within the gene. The characteristics of the encoded 62,600-Da protein, including a potential amino-terminal signal sequence, a hydrophobic carboxy-terminus, and a large number of potential O-glycosylation sites, are consistent with the properties of GP72. No sequence homologies were found in searches of DNA and protein data banks. GP72 is encoded by a single pair of non-telomeric allelic genes.

Variations induced by different methodologies in Trypanosoma cruzi surface antigen profiles

An attempt was made to reconcile published data on the cell surface profile of Trypanosoma cruzi epimastigotes. Cloned parasites were used to compare the effects of centrifugal forces, radioiodination catalyst and protein solubilization methods on the autoradiographic profile of putative surface antigens. Harvesting and washing procedures, and antigen extraction methods, greatly influenced the results obtained, whilst the iodination catalyst was not of critical importance. Mobility in different gel electrophoresis systems, Western blots and partial proteolysis maps indicated that two previously described epimastigote-specific surface antigens (GP72 and Mr 75,000) possibly are distinct molecules.

Intracellular mechanisms of killing.

One of the principal physiologic functions of “professional” phagocytic cells (neutrophils, eosinophils, and mononuclear phagocytes) is to ingest and destroy microorganisms. Mononuclear phagocytes, however, may also provide a favorable environment for the survival and multiplication of a variety of intracellular pathogens, including many obligate intracellular parasites.

Activation of Mononuclear Phagocytes for the Destruction of Intracellular Parasites: Studies with Trypanosoma cruzi

Trypanosoma cruzi is an obligate intracellular parasite of man and other mammals. In man, it produces a chronic infection which, in its more severe form, leads to cardiac damage and failure (Chagas disease).