Monoclonal antibodies against Trypanosoma cruzi neuraminidase reveal enzyme polymorphism, recognize a subset of trypomastigotes, and enhance infection in vitro
Prioli, R.P.; Mejia, J.S.; Pereira, M.E.
Journal of Immunology 144(11): 4384-4391
1990
ISSN/ISBN: 0022-1767 PMID: 2111345 Document Number: 354476
The identification and characterization of 2 murine MAbs (TCN-1 and TCN-2) that react with the neuraminidase of T. cruzi is reported. The MAbs were identified based on their ability to inhibit enzyme activity and recognize neuraminidase in crude enzyme preparations. TCN-1 and TCN-2 recognized antigen in tissue culture trypomastigotes but not in the amastigotes, epimastigotes, or metacyclic trypomastigotes using immunoblot assays and immunofluorescence. In addition, clones Y-H6, MV-13, and Silvio X-10/4 of T. cruzi revealed a unique banding pattern characteristic of each clone. In Silvio X-10/4, the MAb recognized 4 distinct bands ranging from 121 000 to 203 000 MW whereas in Y-H6 and MV-13 they identified bands ranging from 138 000 to 222 000 MW. Characterization of neuraminidase by 2-dimensional PAGE revealed the polypeptides that make up the enzyme to have isoelectrical points ranging from 6.55 to 7.30. Immunofluorescence and C-mediated lysis assays showed that the MAb reacted with a subset of trypomastigotes representing 28% of the total parasite population. Functional studies showed that the MAb enhanced infection of cultured cells by trypomastigotes. The experiments confirm previous findings with polyclonal antibodies and are in accordance with the hypothesis that neuraminidase modulates infection through a negative control mechanism.