The picture exhibits an immune cell that has been contaminated by Toxoplasma parasites (purple). The floor of the cell is coloured inexperienced and the nucleus of the cell is blue. Credit score: Antonio Barragan
A big portion of individuals on the planet is contaminated with the parasite Toxoplasma. Now, a examine headed by scientists at Stockholm College demonstrates how this tiny parasite spreads so efficiently all through the physique, for instance to the mind. The parasite infects immune cells and hijacks their id. The analysis was not too long ago revealed within the journal Cell Host & Microbe.
The varied roles of immune cells within the physique are very strictly regulated as a way to fight infections. How Toxoplasma infects so many individuals and animal species and spreads so rapidly has lengthy been a thriller to scientists.
“We have now now found a protein that the parasite makes use of to reprogram the immune system”, says Arne ten Hoeve, a researcher on the Division of Molecular Biosciences, Wenner-Gren Institute at Stockholm College.
In line with the analysis, the parasite injects the protein into the immune cell’s nucleus, altering the cell’s id. Immune cells are deceived by the parasite into believing they’re a unique type of cell. This alters the immune cell’s gene expression and habits. Toxoplasma causes contaminated cells that ought to not journey within the physique to maneuver rapidly, permitting the parasite to unfold to completely different organs.
A number of immune cells which have been contaminated by Toxoplasma parasites (purple). The floor of the cell is coloured inexperienced and the nucleus of the cell is blue. Credit score: Antonio Barragan
Toxoplasma has been described as changing immune cells into Trojan horses or wandering “zombies” that unfold the parasite. The not too long ago revealed analysis offers a molecular clarification for the phenomenon and demonstrates how the parasite is rather more focused in its unfold than beforehand thought.
“It’s astonishing that the parasite succeeds in hijacking the id of the immune cells in such a intelligent method. We imagine that the findings can clarify why Toxoplasma spreads so effectively within the physique when it infects people and animals,” says Professor Antonio Barragan, who led the examine, which was carried out in collaboration with researchers from France and the USA.
Info relating to the parasite Toxoplasma and the illness toxoplasmosis
Toxoplasmosis might be the most typical parasitic an infection in people globally. Toxoplasma additionally infects many animal species (zoonosis), together with our pets. The WHO has estimated that no less than 30% of the world’s human inhabitants is a provider of the parasite. Research point out that 15-20% of the Swedish inhabitants carry the parasite (the overwhelming majority with out understanding it). The incidence is greater in a number of different European nations.
Felines, not simply home cats, have a particular place within the life cycle of Toxoplasma: it’s only within the cat’s gut that sexual copy takes place. In different hosts, for instance, people, canine, or birds, copy takes place by the parasite dividing.
Toxoplasma is unfold by meals and make contact with with cats. In nature, the parasite spreads preferentially from rodents to cats to rodents and so forth. The parasites are “sleeping” within the rodent’s mind and when the cat eats the mouse, they multiply within the cat’s gut and are available out by way of the feces. The parasite leads to the vegetation and when the rodent eats the vegetation it turns into contaminated. People turn out to be contaminated by meat consumption or by contact with cats, particularly cat feces.
The parasite causes the illness toxoplasmosis. When an individual is contaminated for the primary time, gentle flu-like signs happen that may resemble a chilly or the flu. After the primary an infection part, the parasite transitions to a “sleeping” stage within the mind and begins a continual silent an infection that may final for many years or for all times. The continual an infection normally causes no signs in wholesome people. Toxoplasma can, nonetheless, trigger a life-threatening mind an infection (encephalitis) in folks with a weakened immune system (HIV, organ transplant recipients, after chemotherapy) and will be harmful to the fetus throughout being pregnant. Eye infections can happen in in any other case wholesome people.
Reference: “The Toxoplasma effector GRA28 promotes parasite dissemination by inducing dendritic cell-like migratory properties in contaminated macrophages” by Arne L. ten Hoeve, Laurence Braun, Matias E. Rodriguez, Gabriela C. Olivera, Alexandre Bougdour, Lucid Belmudes, Yohann Couté, Jeroen P.J. Saeij, Mohamed-Ali Hakimi and Antonio Barragan, 28 October 2022, Cell Host & Microbe.
DOI: 10.1016/j.chom.2022.10.001
The examine was funded by the Swedish Analysis Council, the Olle Engkvist Byggmastare Basis, ProFI, the Chemistry Biology Well being (CBH) Graduate Faculty of College Q13 Grenoble Alpes, Laboratoire d’Excellence (LabEx) ParaFrap, the Agence Nationale pour la Recherche, and the Fondation pour la Recherche Medicale.