New research by Francis Crick Institute scientists shows that
mice simultaneously infected with gastrointestinal worms and the
parasite that causes malaria will focus their immune response on
the more dangerous malaria parasite, allowing the worms to persist
long-term.
The research identifies complexities relating to simultaneous
infection with the worms, called helminths, and the malaria
parasite, called Plasmodium. The work was led by Drs Mark Wilson
and Jean Langhorne, currently based at Mill
Hill.
Dr Wilson said: "Helminth worms infect almost a third of the
world's population, with many of them causing long-term infections
and significant illness. In areas where helminth infections are
widespread, co-infections with other parasites, bacteria and
viruses are more common than single helminth
infections."
The scientists used state-of-the-art molecular biology
techniques to simultaneously track single immune cells
responding to the helminth infection or the malaria parasite
infection or, in some cases, both. This showed that when the mice
were infected with the malaria parasite as well as the helminth,
the immune cells that were responding to the helminth infection
completely changed their focus and started responding to the
malaria parasite instead.
This preferential response to more life-threatening infections
may come at the cost of allowing less-pathogenic parasites to
persist, contributing to chronic infection, suggest the
researchers.
Dr Wilson said: "This study highlights the complexity of
co-infection and specifically identifies the demands
placed upon the host immune system during co-infection.
Reducing the frequency of life-threatening infections such as
malaria may enhance the effectiveness of anti-helminth
treatments."
The paper, IFN? and IL-12 Restrict Th2 Responses During
Helminth/<i>Plasmodium</i> Co-infection and Promote
IFN? from Th2 Cells, is published in PLOS
Pathogens.