Trypanosoma cruzi: localization of neuraminidase on the surface of trypomastigotes.

Immunoelectron microscopy (IEM) using TCN-2, a monoclonal antibody specific for Trypanosoma cruzi neuraminidase (NA), was performed to determine the precise localization of the parasite enzyme. In agreement with previous observations, TCN-2 reacted with tissue culture trypomastigotes, but not with epimastigotes, amastigotes or intracellular forms in intermediate stages of development. NA was localized on the surface of tissue culture trypomastigotes and in the Golgi apparatus suggesting that the enzyme is modified post-translationally. In agreement with this suggestion, digestion of NA with N-Glycanase, an enzyme that releases N-linked oligosaccharides, decreased the molecular weight of the polypeptides that make up NA.