Publication Q&A: Partial Protection Against P. vivax Infection Diminishes Hypnozoite Burden and Blood Stage Relapses
May 2021 – Dr. Noah Sather shares insights from a recent publication in Cell Host & Microbe. Seattle Children’s contributing authors include Noah Sather, PhD and Stefan Kappe, PhD.
Partial protection against P. vivax infection diminishes hypnozoite burden and blood stage relapses
Carola Schäfer, Nicholas Dambrauskas, Laura M. Reynolds, Olesya Trakhimets, Andrew Raappana, Erika L. Flannery, Wanlapa Roobsoong, Jetsumon Sattabongkot, Sebastian A. Mikolajczak, Stefan H.I. Kappe, D. Noah Sather
Published May 12, 2021
Read this publication in Cell Host & Microbe.
What are the significant findings in this paper?
We are the first to show evidence that a vaccine against Plasmodium vivax (P. vivax) that is imperfect, or does not impart sterilizing immunity, could have a disproportionally large impact on the infection and transmission rates. A major roadblock for malaria vaccines is that is it must be perfect and stop all parasites from reaching the liver, otherwise infection with even a single parasite can drive the infection and transmission cycle. P. vivax is a little different in its behavior, as it forms dormant parasite, called hypnozoites, which can reactivate for months or years, each time causing a transmissible infection. In fact, relapses are thought to drive about 70-90% of transmission. In this paper we found that reducing the number of P. vivax parasites infecting the liver also reduced the number of relapse infections, even in the absence of full protection. Thus, even an imperfect P. vivax vaccine would reduce transmission by reducing the incidence of relapse infections. We believe this finding will be a guiding principle for P. vivax vaccine research moving forward.
What are the next steps and long-term goals for this research?
The current study was conducted in a mouse model system using a monoclonal antibody. The next steps are to translate this to human clinical trial and to study whether live vaccination also reduces relapse infections and if so, by how much.
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The Kappe Lab is focused on understanding the complex biology of the malaria parasite and the immune responses to infection, using this information to design transformational interventions that will help win the fight against malaria.
The Sather Lab utilizes state-of-the-art technology to develop novel vaccine immunogens and strategies. In addition, the lab is interested in deciphering the mechanisms of antibody-mediated protective immunity by HIV or malaria vaccination.