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CD8 + cytotoxic T lymphocytes can kill host cells infected with various microorganisms as well as individual cancer cells by direct cell-to-cell contact, but their ability to destroy a large mbad target remains unexplored. A study in The American Journal of Pathology, published by Elsevier, provided new evidence on the ability of the immune system to eliminate bulky cysts filled with parasites badociated with Toxoplasma gondii (T. gondii) infection using the aggressive invasive activity of cytotoxic T lymphocytes. They can also be effective in attacking other important targets, including solid cancers.
"The present study clearly shows that the immune system is able to attack and eliminate tissue cysts from T. gondii. This highlights the possibility of developing a vaccine to activate these invasive cytotoxic T lymphocytes in order to prevent the establishment of chronic infection with this parasite. This vaccine can also be applied to people who are chronically infected with T. gondii eradicate existing tissue cysts from the parasite and cure this chronic generalized infection. This study also suggests the possibility of developing a new anti-cancer immunotherapy that can be used to eliminate various types of solid cancers by activating invasive cytotoxic T cells that attack and penetrate specifically into targeted cancers, "said lead researcher Yasuhiro Suzuki, PhD, Department of Microbiology, Immunology and Molecular Genetics, College of Medicine, University of Kentucky, Lexington, KY, USA.
One-third of the world's human population and many other warm-blooded animals are currently infected with the virus. T. gondii. Although T. gondii Latent infection can usually turn into a serious and sometimes fatal illness, toxoplasmic encephalitis, especially in immunodeficient people such as cancer, HIV / AIDS or organ transplants. In addition, recent epidemiological studies have reported an increased incidence of brain cancer in T. gondiiinfected people. Chronic infection is badociated with the formation of cysts up to 50 m in diameter, filled with hundreds to thousands of parasites, most commonly found in the brain, eyes and striated muscle, including the heart. . A common cause of T. gondii The infection is the consumption of tissue cysts in raw or undercooked meat of infected animals, such as pork and mutton.
In this study, scientists investigated the effects of an injection of purified CD8 + immunized T cells from the spleen of chronically infected mice in mice ingested several T. gondii cysts. A few days after the injection of T lymphocytes, the number of T. gondii Cysts completely invaded by T cells were found in the brain of mice injected with immune T cells.
Cysts invaded by T cells showed structural signs of deterioration and destruction. Within these deteriorated cysts, the granular structures appeared to be intensely positive for granzyme B, a major cytotoxic protein secreted by cytotoxic T cells. These granular structures have been detected in badociation with T. gondii the bradyzoites (the encysted form of the parasite multiplying slowly badociated with the dormant stage of the infection). In addition, the bradyzoites in the destroyed cysts were located in accumulated trapping cells, including microglia and macrophages. Researchers have also shown that perforin (a protein released by immune system killer cells, which destroys targeted cells by creating pore-like lesions in their membranes) was necessary for the CD8 + T cell invasion process. cyst elimination.
In addition to becoming a powerful weapon against T. gondii the researchers suggest that the same principles can be used to fight against solid cancers. "Invasion of T cells in tumors could induce infiltration of a large number of phagocytic cells capable of attacking cancer cells, as has been observed against T. gondii Cysts, "noted Dr. Suzuki. Effective activation of cytotoxic T lymphocyte penetration, which specifically recognizes targeted solid cancers, will most likely become a powerful therapeutic approach for various types of solid cancers. "
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Material provided by Elsevier. Note: Content can be changed for style and length.
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