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Rescuing lymphocytes from HLA-G immunosuppressive effects mediated by the tumor microenvironment

Several studies have demonstrated that the antitumor activities of both T and natural killer (NK) effector populations are limited by the immunosuppressive strategies of tumors. In several malignant transformations, the expression of HLA-G by tumor cells rises dramatically, rendering them strongly i...

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Detalles Bibliográficos
Autores principales: Wu, Danli, Kuiaste, Isere, Moreau, Philippe, Carosella, Edgardo, Yotnda, Patricia
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Impact Journals LLC 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4741936/
https://www.ncbi.nlm.nih.gov/pubmed/26460949
Descripción
Sumario:Several studies have demonstrated that the antitumor activities of both T and natural killer (NK) effector populations are limited by the immunosuppressive strategies of tumors. In several malignant transformations, the expression of HLA-G by tumor cells rises dramatically, rendering them strongly immunosuppressive. In this study, we postulated that the absence of HLA-G receptors would prevent the immunosuppressive effects of both soluble and membrane-bound HLA-G. Thus, we investigated the therapeutic potential of effector NK cells genetically modified to downregulate the expression of ILT2 (HLA-G receptor) on their cell surfaces. We have shown that the proliferation of modified NK is still dependent on stimulation signals (no malignant transformation). ILT2(−) NK cells proliferate, migrate, and eliminate HLA-G negative targets cells to the same extent parental NK cells do. However, in the presence of HLA-G positive tumors, ILT2(−) NK cells exhibit superior proliferation, conjugate formation, degranulation, and killing activities compared to parent NK cells. We tested the effectiveness of ILT2(−) NK cells in vivo using a xenograft cancer model and found that silencing ILT2 rescued their anti-tumor activity. We believe that combining ILT2(−) NK cells with existing therapeutic strategies will strengthen the antitumor response in cancer patients.