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Natural Killer Cell Function (natural + killer_cell_function)
Selected AbstractsPersistent inhibition of human natural killer cell function by ziram and pentachlorophenolENVIRONMENTAL TOXICOLOGY, Issue 4 2005Thyneice R. Taylor Abstract Ziram is a currently used agricultural fungicide. It is also used as an additive in the production of latex gloves. Because of these uses, there is a potential for human exposure to this compound. Pentachlorophenol (PCP) has been used as an insecticide, fungicide, disinfectant, and ingredient in antifouling paints. Currently, it is used as a wood preservative for power-line poles and fence posts. Measurable levels of PCP have been detected in human blood and urine. In previous studies we demonstrated that both these compounds could cause very significant inhibition of the tumor-killing function of human natural killer (NK) cells. NK lymphocytes play a central role in immune defense against viral infection and the formation of primary tumors. So interference with their function could increase the risk of tumor development. In the present study we examined the effects of exposure to ziram or PCP of brief duration (1 h) on the ability of NK cells to destroy tumor cells. NK cells were exposed to either ziram (5,0.5 ,M) or PCP (10,5 ,M) for 1 h followed by 0 h, 24 h, 48 h, or 6 days in compound-free media and then were tested for the ability to lyse as well as to bind tumor cells. A 1-h exposure to as little as 2.5 ,M ziram decreased the ability of NK cells to lyse target tumor cells, which persisted up to 6 days following exposure. The loss of lytic function for from 24 h to 6 days following exposure was accompanied by a comparable loss of NK capacity to bind tumor cells. Exposure to 10 ,M PCP for 1 h caused a progressive loss (greater than 80%) of lytic function within 6 days of exposure. In contrast to ziram, PCP exposure caused no accompanying loss of binding function. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 418,424, 2005. [source] REVIEW ARTICLE: Evolution and Function of the Uterine Serpins (SERPINA14)AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 4 2010Maria B. Padua Citation Padua MB, Hansen PJ. Evolution and function of the uterine serpins (SERPINA14). Am J Reprod Immunol 2010 Uterine serpins (recently designated as SERPINA14) are hormonally induced proteins secreted in large quantities by the endometrial epithelium during pregnancy. The SERPINA14 proteins belong to the serine proteinase inhibitor (serpin) superfamily, but their apparent lack of inhibitory activity toward serine proteinases suggests that these proteins evolved a different function from the anti-proteinase activity typically found in most members of the serpin superfamily. The gene is present in a limited group of mammals in the Laurasiatheria superorder (ruminants, horses, pigs, dolphins and some carnivores) while being absent in primates, rodents, lagomorphs and marsupials. Thus, the gene is likely to have evolved by gene duplication after divergence of Laurasiatheria and to play an important role in pregnancy. That role may vary between species. In sheep, SERPINA14 probably serves an immunoregulatory role to prevent rejection of the fetal allograft. It is inhibitory to lymphocyte proliferation and natural killer cell function. In the pig, SERPINA14 is involved in iron transport to the fetus by binding to and stabilizing the iron-binding protein uteroferrin. It is possible that SERPINA14 has undergone divergence in function since the original emergence of the gene in a common ancestor of species possessing SERPINA14. [source] Defective phosphorylation of interleukin-18 receptor , causes impaired natural killer cell function in systemic-onset juvenile idiopathic arthritisARTHRITIS & RHEUMATISM, Issue 9 2009Wilco de Jager Objective Systemic-onset juvenile idiopathic arthritis (JIA) is an autoimmune disease characterized by arthritis and systemic features. Its pathogenesis is still largely unknown. It is characterized immunologically by natural killer (NK) cell dysfunction and cytokine signatures that predominantly feature interleukin-1 (IL-1), IL-6, and IL-18. Since IL-18 can drive NK cell function, we examined how the high plasma levels of this cytokine are related to the documented NK cell failure in these patients. Methods The phenotype and function of NK cells from 10 healthy control subjects, 15 patients with polyarticular JIA, and 15 patients with systemic-onset JIA were characterized by staining and functional assays in vitro. IL-18 ligand binding was visualized by fluorescence microscopy. Phosphorylation of several MAP kinases and the IL-18 receptor , (IL-18R,) were visualized by Western blotting. Results IL-18 from the plasma of systemic-onset JIA patients stimulated the activation of NK cells from healthy controls and bound its cognate receptor. However, NK cells from systemic-onset JIA patients failed to up-regulate cell-mediated killing molecules, such as perforin and interferon-,, after IL-18 stimulation. Furthermore, treatment with IL-18 did not induce the phosphorylation of receptor-activated MAP kinases in NK cells. Alternate activation of NK cells by IL-12 induced NK cell cytotoxicity. We observed no additive effect of IL-18 in combination with IL-12 in systemic-onset JIA patients. Immunoprecipitation of IL-18R, showed that NK cells from systemic-onset JIA could not phosphorylate this receptor after IL-18 stimulation. Conclusion The mechanism of the impaired NK cell function in systemic-onset JIA involves a defect in IL-18R, phosphorylation. This observation has major implications for the understanding and, ultimately, the treatment of systemic-onset JIA. [source] Immune escape and exploitation strategies of cytomegaloviruses: impact on and imitation of the major histocompatibility systemCELLULAR MICROBIOLOGY, Issue 8 2004Edward S. Mocarski Jr Summary Cytomegalovirus (CMV) has yielded many insights into immune escape mechanisms. Both human and mouse CMV encode a diverse array of gene products, many of which appear to modulate the immune response in the host. Some deflect the host response to infection and contribute to lifelong viral persistence while others exploit immune cells that respond to infection. Here, the viral functions that modulate and mimic host major histocompatibility complex (MHC) function will be reviewed. Viral gene products related to both classical and non-classical components of the MHC system assure the virus will persist in immunocompetent individuals. Examples of host countermeasures that neutralize viral immunomodulatory functions have emerged in the characterization of viral functions that contribute to this stand-off in CMVs that infect humans, other primates and rodents. CMV-induced disease occurs when the immune system is not yet developed, such as in the developing fetus, or when it is compromised, such as in allograft transplant recipients, suggesting that the balance between virus escape and host control is central to pathogenesis. Although evidence supports the dominant role of immune escape in CMV pathogenesis and persistence, MHC-related immunomodulatory functions have been ascribed only subtle impact on pathogenesis and the immune response during natural infection. Viral gene products that interface with the MHC system may impact natural killer cell function, antigen presentation, and T lymphocyte immune surveillance. Many also interact with other cells, particularly those in the myeloid lineage, with consequences that have not been explored. Overall, the virus-encoded modulatory functions that have been acquired by CMV likely ensure survival and adaptation to the wide range of mammalian host species in which they are found. [source] Neonatal liver failure and haemophagocytic lymphohistiocytosis caused by a new perforin mutationACTA PAEDIATRICA, Issue 5 2010O Danhaive Abstract Acute liver failure is a rare heterogeneous syndrome in neonates. We report of a newborn with haemophagocytic lymphohistiocytosis presenting as acute liver failure. Pancytopenia and multi-organ failure occurred later in the course. He carried two mutations of the perforin gene (PRF-1), one of which not previously described, causing a complete loss of perforin expression and natural killer cell function. Conclusion:, Perforin expression and function should be promptly assessed in neonatal/infantile acute liver failure, as haemophagocytic lymphohistiocytosis requires specific treatment and represents a contra-indication to liver transplant. [source] | ||||||||||