Promoter: Prof. Dr. JWR Hovius
Introduction researcher
Alexis joined the AUMC as a doctoral researcher in 2020. She previously completed her B.Sc. in Animal Sciences with highest honors from the University of Tennessee, Knoxville (USA). After working in microbiology research at Oak Ridge National Laboratory, she joined the inaugural class of the Erasmus Mundus Joint M.Sc. program in Infectious Diseases and One Health (IDOH) at the University of Edinburgh, Université de Tours, and Universitat Autònoma de Barcelona. With a broad background in biomedical and veterinary research, she has a strong interest in vector-borne and zoonotic diseases. Among other topics, her previous work has examined methods of zoonotic leishmaniosis control in dogs and wild rabbits and dogs’ immune response to the saliva of sandflies, which transmit leishmaniosis.
Reason for the research
Currently, there is no human vaccine available against Lyme borreliosis (LB) the most common vector-borne disease in the Northern Hemisphere. LB is caused by Borrelia spirochetes transmitted by Ixodes ticks, which can be found in many parts of the world. Despite issues with underreporting, cases of LB have grown exponentially in the US and Europe over the past years. In the Netherlands alone, the number of diagnoses has quadrupled over the last 20 years. Moreover, its burden is expected to grow with the expanding geographical range of Ixodes tick species due to global climate change.
When a tick bites, it not only introduces pathogens like Borrelia but also other substances, called salivary proteins. These tick salivary proteins allow the tick to remain attached to the host’s skin and continue feeding, in addition to promoting the transmission of the pathogen itself. For example, many of these proteins interfere with blood clotting, anchor the tick to the skin, or prevent host immune cells from destroying spirochetes.
These proteins are also responsible for a phenomenon called tick immunity, in which some animals repeatedly bitten by ticks develop a strong immune reaction to ticks that interferes with feeding. When the ticks fall off or cannot complete feeding, they are unable to transmit the pathogen. Therefore, tick immune animals are effectively protected from developing the disease.
In this project, we hope to create an anti-tick vaccine for LB by finding the correct combination of proteins to mimic this natural phenomenon, providing protection against LB as well as other tick-borne diseases (TBDs) simultaneously.
Purpose of the study:
The project’s overarching goal is to develop a novel, broadly-protective vaccine for the prevention of LB and other TBDs. We believe we can accomplish this goal by combining Borrelia proteins with tick salivary proteins in a single vaccine.
Broader Explanation of the Research:
Previous and ongoing research in the group has identified a series of novel vaccine candidates, encompassing proteins from the causative pathogen (Borrelia), as in previous vaccines, as well as from the vector (Ixodes ticks). Because different species of Borrelia cause LB in different parts of the world, we hope to provide broader protection than previous vaccines by selecting those proteins that are relatively similar among the species.
The function of these proteins will be characterized in this project, providing much-needed insight into the complex tick-host-pathogen relationship. Promising candidates will then be evaluated for their immunogenicity and efficacy in a tick-Borrelia-mouse model using different adjuvants and vaccine platforms.
Researchers
AUMC location AMC
Prof. Dr. JWR Hovius (Principal Investigator)
Dr. Abhijeet Nayak