Proteomic analyses in Giardia .

Abstract

AbstractThe parasitic protozoan Giardia intestinalis is a worldwide cause of diarrhoea, but the mechanism of disease remains elusive. The parasite colonizes the small intestinal epithelium, known to be a sensor for the presence of enteric pathogens, without invading or causing severe inflammation. Proteomics has been used to study various aspects of Giardia-host interactions. Giardia can differentiate between a cyst and trophozoite stage in response to environmental stimuli. There are relatively large changes in the RNA expression but proteomic analyses showed only small changes in the proteome. This shows that many proteins, used in trophozoites, are stored in the cysts. Secretory antibodies are important for clearance of Giardia. Proteomic analyses have been used to identify the major antigens in Giardia and these proteins can be used in the development of new diagnostic methods or vaccines. Excretory-secretory products of pathogenic microbes often play important roles in host-parasite interactions. Using a proteomics approach, we have identified the major proteins in the culture supernatant after in vitro interaction between Giardia intestinalis and human intestinal epithelial cell lines. The importance of the secreted proteins during host-parasite interactions has been further studied. Giardia genome sequencing and data mining indicate that many basic biological processes are reduced in Giardia compared with the corresponding processes in other eukaryotes. Proteomic analyses of specific cellular structures or molecular complexes will be important in future Giardia research.