Date of Award

8-28-2013

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Applied Science

First Advisor

Thomas Lynch

Abstract

Toxoplasmosis is a parasitic disease caused by the intracellular protozoan Toxoplasma gondii your words (T. gondii your words) that affects most types of warm-blooded vertebrate cells. Up to one third of the humans population in the world is chronically infected by this parasite. Human and animals at risk for toxoplasmosis include fetuses, newborns, and immunologically impaired patients. To date, there is no vaccine available and no drug has a successful effective against chronic form of toxoplasmosis. Recent Toxoplasma your words diagnostic methods showed high false positive results and cannot detect the parasite in the early infection stage. Early diagnosis of tachyzoites (Tg) can prevent the chronic toxoplasmosis.Development of new diagnostic and treatments methods against toxoplasmosis with less toxicity are essential. The synthetic polymeric carbohydrates bearing moieties (SPCs) possess numerous bactericidal and immunodulatory properties and are becoming essential tools for studying carbohydrate-based interaction processes including recognition, invasion, and parasitism. In this study, we evaluate the efficacy of SPCs on the: (1) early recognition of T. gondii your words by assessing the binding affinity of SPCs toward tachyzoites, (2) controlling parasite invasion, killing tachyzoites and enhance immune cells viability by studying the tachyzoites infection ability in the presence of SPCs in vitro and in vivo, (3) triggering host immunity by increasing the signaling cascades of the immune cells and demonstrate their microbicidal activity in vitro your words and in vivo your words. Different types of SPCs displayed significant binding affinities towards live tachyzoites. Result obtained from plaque assay and fluorescent microscopy using double-label immunocytochemical staining (DIHCS) showed that SPC4, SPC5 and SPC8 were the best candidates that inhibited T. gondii your words tachyzoites invasion or replication and protected cells from death. Peritoneal murine macrophage functional analyses were performed using MAPK analysis, nitric oxide (NO) determination, and cytotoxicity protection by measuring lactate dehydrogenase (LDH) activity, upon exposure to Toxoplasma your words treated by SPCs. Cell viability, necrosis, and apoptosis were assessed by fluorescence-activated cell sorting (FACS). In vivo your words studies, treatment with SPCs triggered immune cell activities by increasing cytokine production and recruited more phagocytic types of leukocytes to the site of the infection. Treatment with SPCs decreased the number of tachyzoites of the site of infection, suggesting that SPCs promote phagocytosis by modulating tachyzoites surface and preventing a systemic dissemination of the parasite. The data suggested by our study can be useful in pharmacological treatment and could be exploited for a generation of novel glycolengineered structures that may have applications as promising candidates for carbohydrate based immunotherapeutic and/or vaccines against T. gondii your words tachyzoites and other apicomplexan parasites. New SPC candidates will impact further research on finding new methods for early T. gondii your words recognition.

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