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CC BY-NC V4.0, Open Access
Dissertation
FUNCTIONAL AND IMMUNOLOGICAL CHARACTERIZATION OF CLAMP AND RAP-1 PROTEINS IN THEILERIA EQUI
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000005410
Handle:
https://hdl.handle.net/2376/119611
Abstract
Theileria equi (T. equi) is one of the causative agents of equine piroplasmosis, a severe tick-transmitted disease that affects most equid species. Control of the parasite is impeded by the lack of an effective vaccine and the fact that it can be transmitted by multiple tick vectors. T. equi is classified within the phylum Apicomplexa due to the presence of secretory organelles (micronemes, rhoptries and dense granules) on the apical end of the parasite that are essential for invasion and establishment of apicomplexans within host cells. Unlike most apicomplexan species, the roles of these organelles, and their contents in host cell invasion remain unexplored in T. equi. In chapter one, we evaluate the role of T. equi micronemes by assessing the role of the claudin like apicomplexan microneme protein (CLAMP) in erythrocyte invasion and identify equine erythrocyte components that interact with the protein during cell entry. We also assess expression of CLAMP in the merozoite and intra-erythrocytic developmental stages of T. equi and evaluate its immunogenicity as a potential vaccine candidate. The results show that the protein is expressed in both developmental stages and elicits significant antibody responses in horses during T. equi infection, indicating that it is a viable candidate for vaccine development. The results also show that CLAMP is involved in invasion of equine erythrocytes and the protein interacts with key components of the equine erythrocyte cytoskeleton during cell entry. In chapter two, we evaluate the role of T. equi rhoptries in invasion. In this regard, we assess the expression of the rhoptry associated protein-1a and -1b (RAP-1a and RAP-1b) in the merozoite and intra-erythrocytic developmental stages of T. equi and evaluate their immunogenicity and roles in invasion. Our findings show that both proteins are expressed in both developmental stages and while RAP-1a is highly immunogenic and involved in erythrocyte entry, the N- and C-termini of RAP-1b are not required for cell entry and are not immunogenic. In conclusion, our findings show that like most apicomplexan species, the T. equi secretory organelles are involved in invasion and their contents can be targeted for vaccine development.
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Details
- Title
- FUNCTIONAL AND IMMUNOLOGICAL CHARACTERIZATION OF CLAMP AND RAP-1 PROTEINS IN THEILERIA EQUI
- Creators
- Cynthia Onzere
- Contributors
- Donald P Knowles (Advisor)Carlos E Suarez (Advisor)Lindsay M Fry (Committee Member)Roberta O'Connor (Committee Member)Richard P Bishop (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- College of Veterinary Medicine
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 106
- Identifiers
- 99900592359501842
- Language
- English
- Resource Type
- Dissertation