Identification of a developmentally regulated sialidase inEimeria tenella that is immunologically related to theTrypanosoma cruzi enzyme |
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| Authors: | Jean-Luc J. Pellegrin Eduardo Ortega-Barria Reginaldo P. Prioli Mary Buerger Richard G. Strout Joseph Alroy Miercio E. A. Pereira |
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| Affiliation: | (1) New England Medical Center Hospitals, Department of Medicine, Division of Geographic Medicine and Infectious Diseases, 750 Washington Street, 02111 Boston, MA, USA;(2) Department of Animal and Nutritional Sciences, University of New Hampshire, Durham, NH, USA;(3) Department of Pathology, Tufts University School of Medicine and Veterinary Medicine, Boston, MA, USA;(4) Present address: Clinique de Medecine Interne, Hopital Haut-Leveque, 33604 Pessac, France;(5) Present address: Immunobiologicals Department, Genzyme Corporation, One Kendall Square, 02139 Cambridge, MA, USA |
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| Abstract: | Sporozoites and merozoites of three species ofEimeria, E. tenella, E. maxima, andE. necatrix, that cause diarrhea in chickens worldwide, were examined for their expression of sialidase (SA) activity. The enzyme was found in three species, and the activity of merozoites was 10–20 times higher than that of sporozoites. The enzyme was resistant to degradation by proteases that are normally present in the intestine, a site inhabited by theEimeria parasites, and it was relatively resistant to heat, with optimum activity being at 40°C, which is within the range of temperature in the chicken intestine (40–43°C).E. tenella SA was immuniprecipitated by monoclonal and polyclonal antibodies raised against theTrypanosoma cruzi SA (TCSA), and enzyme activity was neutralized by these antibodies.E. tenella SA was identified by immunoblots as a doublet of molecular weight 190 000 and 180 000 using, as a probe, anti-TCSA antibodies and antibodies against a synthetic peptide (TR) derived from the long tandem repeat domain of TCSA. Binding of the monoclonal and polyclonal antibodies toE. tenella was completely blocked by TR, but not by an irrelevant peptide (BR). Therefore,E. tenella expresses a developmentally regulated SA that is structurally related to theT. cruzi counterpart. Because of the high SA activity in merozoites, and by analogy with other SA-producing microbes that inhabit mucin-rich epithelia, we suggest that theEimeria SA plays a role in desialylating intestinal mucins to reduce viscosity of the local environment and thereby facilitate parasite migration. The enzyme could also play a role in host cell-parasite interaction.Abbreviations SA sialidase (neuraminidase) - Neu5Ac N-acetylneuraminic acid - 4-MU-Neu5Ac 2 -(4-methylumbelliferyl)- -N-acetyl-d-neuraminic acid - BSA bovine serum albumin - PBS phosphate buffered saline - PMSF phenylmethylsulfonyl fluoride - PNA peanut agglutinin - Ab antibody - TCN-2 monoclonal antibody toT. cruzi sialidase, anti-Ars, monoclonal antibody top-azophenylarsonate - TCSA Trypanosoma cruzi sialidase |
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| Keywords: | Eimeria spp Trypanosoma cruzi neuraminidase TCN-2 |
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