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Title: Imunolocalization of delta-giardin within the ventral disc of Giardia duodenalis using laser scanning confocal microscopy

item Macarisin, Dumitru
item Obrien, Celia
item Bauchan, Gary
item Fayer, Ronald
item Jenkins, Mark

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2011
Publication Date: 4/27/2011
Citation: Macarisin, D., Obrien, C.N., Bauchan, G.R., Fayer, R., Jenkins, M.C. 2011. Imunolocalization of delta-giardin within the ventral disc of Giardia duodenalis using laser scanning confocal microscopy. BARC Poster Day.

Interpretive Summary:

Technical Abstract: Giardia duodenalis is a ubiquitous protozoan parasite that colonizes the upper small intestine of humans and animals causing diarrheal disease. To maintain infection within the small intestine, trophozoites (the replicative stage of the parasite) attach to the epithelial layer of the gut and resist its peristaltic movement, bolus flow and continuous shedding of mucus and cells. A unique Giardia organelle, the ventral disc, is believed to play a key role in adherence of trophozoites to epithelial cells of the intestine; however the mechanism of attachment is still unclear. Previous studies demonstrated that antibodies against recombinant delta-giardin inhibited trophozoite adherence to glass microscope slides, suggesting potential role for delta-giardin in pathogen attachment to host epithelium. Current study was conducted to gain insight into the spatial localization of delta-giardin in both trophozoite and cyst stages with the aid of laser scanning confocal microscopy and polyclonal antibodies against recombinant delta-, ß-, and alpha2-giardin. Multiplex immunolocalization of all 3 giardins showed that in trophozoites and encysted forms of the parasite delta-giardin is strictly associated with the ventral disc. Optical sectioning of the ventral discs, together with quantitative measurement of the immunofluorescence for delta- and ß-giardin, demonstrated that these proteins share a great degree of colocalization. Delta-giardin, however, is positioned much more ventrally and therefore represents the actual adhesive side of the disc potentially playing an important role in adhesion. These findings provide further support for the crucial role of delta-giardin in Giardia virulence and highlight the potential of the giardins as promising targets for immunotherapy of giardiasis.