Seattle BioMed Researchers Identify Innate Immune Response to Malaria Parasite Liver Stage Infection

Preclinical Study Published in Cell Reports Identifies Key Signaling Pathways in Innate Immune Sensing of Malaria Parasite During Liver Stage Infection

Apr 03, 2014, 12:04 ET from Seattle BioMed

SEATTLE, April 3, 2014 /PRNewswire/ -- Seattle BioMed today announced researchers have identified the presence of an innate immune response to the malaria parasite during liver stage infection. Results of the study were published online today in Cell Reports.

Key points:

  • Following transmission of the malaria parasite by mosquito bite, the first stage of infection occurs in the liver and is asymptomatic.
  • Given the lack of symptoms, it was previously thought that there was little to no detection of the parasite by the first line of defense, the innate immune response, during this "silent" phase of the infection. 
  • However, researchers at Seattle BioMed have identified a robust innate immune response to the malaria parasite during its first stage of infection in the liver using an animal model.
  • This discovery could be critical for the design of effective pre‐erythrocytic vaccines that aim to prevent malaria infection and may further contribute to the understanding of malaria epidemiology.
  • This innate immune response primarily includes the activation of both type-I interferon and interferon gamma (IFNg) signaling pathways and the infiltration of a subset of immune cells called natural killer T cells into the infected liver.
  • Every minute, a child dies from malaria, a disease that threatens over 40 percent of the world's population, and kills over half a million people each year.
  • Current malaria vaccines are vastly limited in their efficacy. 


Stefan Kappe, Ph.D., principal scientist and corresponding author, Seattle BioMed said, "We identified previously unrecognized, yet critical pathways for how early malaria infection is detected by the host. Mosquitoes transmit relatively few parasites at the time of a bite. Therefore, it was previously thought that this would allow the parasite to stay below the host's immune 'radar' to establish the infection. By understanding more about this early stage of the infection process we can exploit it as an 'Achilles heel' in the parasite life cycle and make it a target for interventions that aim to prevent malaria infection."

Jessica Miller, Ph.D., postdoctoral scientist and lead author, Seattle BioMed said "Since the liver stage of malaria is clinically silent, it was previously thought to be relatively immunologically silent. We have shown that malaria actually induces a robust, functional innate immune response during liver development-- one that can be exploited in the search for new treatments for malaria."

Alan Aderem, Ph.D., president of Seattle BioMed said, "In order to develop effective vaccines against diseases like malaria, it's critical to first gain insight into how the innate immune system recognizes and responds to the parasite. This work is an important step in reaching that goal."


Seattle BioMed is the largest independent, non-profit organization in the U.S. focused solely on infectious disease research. Our research is the foundation for new drugs, vaccines and diagnostics that benefit those who need our help most: the 14 million who will otherwise die each year from infectious diseases, including malaria, HIV/AIDS and tuberculosis. Founded in 1976, Seattle BioMed has more than 330 staff members. By partnering with key collaborators around the globe, we strive to make discoveries that will save lives sooner. For more information, visit

Research reported in this press release was supported by the Bill and Melinda Gates Foundation, under award number OPP1016829. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Bill and Melinda Gates Foundation.

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SOURCE Seattle BioMed