Identification of Dermacentor Andersoni Saliva Proteins that Modulate Mammalian Phagocyte Function
EMSL Project ID
47421
Abstract
Dermacentor andersoni, known as the Rocky Mountain wood tick, is a species of tick found in the western United States. Ticks are obligate blood sucking parasites which transmit a wide range of pathogens worldwide including protozoa, bacteria and viruses. Tick saliva is known to modulate both innate and acquired immune responses, enabling ticks to feed for several days. During this time ticks subvert host defenses such as hemostasis and inflammation, which would result in coagulation, wound repair and rejection of the tick. Consequently, the pathogens transmitted by ticks exploit these immunomodulatory properties to facilitate invasion of and replication in the host. Furthermore, the acaricides developed to control ticks have resulted in the establishment of acaricide resistant tick populations and environmental pollution with resultant killing of non-target organisms. Molecular characterization of the proteins in tick saliva offers an opportunity to develop an anti-tick vaccine as an environmentally friendly alternative to using acaricides. In order to accomplish this, it is necessary to identify D. andersoni salivary proteins that modulate the host immune response. By investigating tick proteins that affect macrophage function, we can begin to understand modulation of the host response by the tick. The first aim is to identify proteins with increased expression in 2 day fed ticks and secreted in saliva, as compared to 5 day fed ticks (day 0 is not included because we are not able to collect saliva from unfed ticks). Proteins with increased expression will be selected for further testing in macrophage models. Selection will be based on the rationale that immunomodulatory proteins will be secreted early during the feeding process. In order to accomplish this task, we have developed an EST library for D. andersoni salivary gland transcripts, as there is no publicly available genomic library for D. andersoni. The EST database will aid in identification of the genes, ultimately proteins, involved in blood feeding. In order to identify and select proteins with increased expression in early fed ticks, our goal is global proteomic analysis of whole saliva. Proteins will be identified by mapping peptides to the EST database developed at WSU and comparing expression levels between early and late-fed ticks. The identified proteins of interest will be expressed by in vitro transcription and translation at WSU, as previously done in Dr. Brown's lab (Lopez et al., 2008; Lawrence et al., 2012). Expressed proteins will be tested in appropriate macrophage models to assess their effect on the immune function of the cells. The methods for assessing macrophage function will include measuring superoxide and nitric oxide production using the chemiluminescent dehydrogenase kit and Griess reagent system respectively. Additionally, cytokine production will be determined using the flow based Bio-Plex multiplex cytokine assay (BioRad). Lastly, we shall determine whether the identified saliva proteins inhibit inflammation in vivo using a mouse paw edema model. At the end of the study we expect to identify novel tick saliva proteins that are potential targets for anti-tick vaccines and drug development.
Project Details
Project type
Limited Scope
Start Date
2012-05-07
End Date
2012-07-07
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Mudenda L, S Aguilar Pierle, JE Turse, GA Scoles, SO Purvine, CD Nicora, TRW Clauss, MW Ueti, WC Brown, and KA Brayton. 2014. "Proteomics informed by transcriptomics identifies novel secreted proteins in Dermacentor andersoni saliva." International Journal for Parasitology. doi:10.1016/j.ijpara.2014.07.003