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Journal of Biomedicine and Biotechnology
Volume 2010 (2010), Article ID 418157, 14 pages
http://dx.doi.org/10.1155/2010/418157
Research Article

Characterization of Major Surface Protease Homologues of Trypanosoma congolense

1Department of Microbiology and Immunology, University of Saskatchewan, A302 Health Science Building, 107 Wiggins Road, Saskatoon, SK, Canada S7N 5E5
2Department of Veterinary Microbiology, University of Saskatchewan, A302 Health Science Building, 107 Wiggins Road, Saskatoon, SK, Canada S7N 5E5

Received 15 July 2009; Accepted 12 October 2009

Academic Editor: Abhay R. Satoskar

Copyright © 2010 Veronica Marcoux et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Trypanosomes encode a family of proteins known as Major Surface Metalloproteases (MSPs). We have identified six putative MSPs encoded within the partially sequenced T. congolense genome. Phylogenic analysis indicates that T. congolense MSPs belong to five subfamilies that are conserved among African trypanosome species. Molecular modeling, based on the known structure of Leishmania Major GP63, reveals subfamily-specific structural variations around the putative active site despite conservation of overall structure, suggesting that each MSP subfamily has evolved to recognize distinct substrates. We have cloned and purified a protein encoding the amino-terminal domain of the T. congolense homologue TcoMSP-D (most closely related to Leishmania GP63). We detect TcoMSP-D in the serum of T. congolense-infected mice. Mice immunized with the amino-terminal domain of TcoMSP-D generate a persisting IgG1 antibody response. Surprisingly, a low-dose challenge of immunized mice with T. congolense significantly increases susceptibility to infection, indicating that immunity to TcoMSP-D is a factor affecting virulence.