Off-campus UMass Amherst users: To download dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.
Non-UMass Amherst users, please click the view more button below to purchase a copy of this dissertation from Proquest.
(Some titles may also be available free of charge in our Open Access Dissertation Collection, so please check there first.)
Virulence-related antigens of African pathogenic trypanosomes and of Trichomonas vaginalis: Possible use in vaccination and diagnosis
Abstract
The first part of this study examines vaccine candidates for African pathogenic trypanosomes. Nonvariant antigens (NVAs) limited to bloodstream form stages of Trypanosoma congolense, have been identified using immunodiffusion, immunoelectrophoresis, and Western blotting techniques. Results from experiments employing surface biotinylation, iodination, and immunogold labeling suggest that these NVAs are exposed on the parasite surface and thus, if appropriately presented might afford the mammalian host a protective immunity. Trypanosoma brucei brucei development in Glossina provides another opportunity to block parasite development via passive immunization against procyclic forms. Results obtained from studies designed to evaluate this possibility suggest that ingested anti-procyclic antibody had little influence on parasite development within Glossina. The apparent resistance of antibody to enzymatic degradation for up to 120 h postingestion, as determined by Western blotting, suggests that antibody inactivation, rather than destruction is responsible for these results and provides a rationale for future investigations. The second part of this study investigates virulence mechanisms and identifies possible diagnostic antigens of the human urogenital protozoan parasite Trichomonas vaginalis. Plasma membrane isolated from T. vaginalis strains differing in virulence contain qualitative but not quantitative differences in their protein composition as determined with the aid of Western blotting. Two proteins in the 150 kDa range appeared more abundant in mild strains, while proteins of 43 and 25 kDa appeared more abundant in the membranes of virulent strains. These latter proteins are apparently heavily glycosylated as indicated by their ability to bind ConA and SBA lectins. Possibly, these glycoproteins may contribute to virulence mechanisms of the parasite. In attempts to develop a reliable diagnostic assay, soluble antigens shed by T. vaginalis were identified using Western blotting techniques. Five soluble antigens were initially identified in supernatant fluids obtained from parasites grown on TYM medium supplemented with 1% normal human plasma (NHP). Four of these proteins immunologically cross-reacted with NHP and are thus of limited diagnostic potential. A 100 kDa antigen, lacking in NHP cross-reactivity, however, could be isolated from all parasite strains examined and maybe of some use in developing a diagnostic assay.
Subject Area
Zoology|Microbiology|Entomology|Pathology
Recommended Citation
Hampton, Robin Wheeler, "Virulence-related antigens of African pathogenic trypanosomes and of Trichomonas vaginalis: Possible use in vaccination and diagnosis" (1991). Doctoral Dissertations Available from Proquest. AAI9120887.
https://scholarworks.umass.edu/dissertations/AAI9120887