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104-P Semaphorin 5A activates NK and T cell responses in an antigen-independent manner
S86
104-P
Abstracts
SEMAPHORIN 5A ACTIVATES NK AND T CELL RESPONSES IN AN ANTIGEN-INDEPENDENT MANNER. Christiane Gras, Britta Eiz-Vesper, Stephan Immenschuh, Rainer Blasczyk, Constanca Figueiredo. Institute for Transfusion Medicine, Hannover Medical SChool, Hannover, Germany. Aim: Semaphorin 5A (Sema5A) was shown to be upregulated in cancer, however its function in the immune system is still unknown. We investigated the effect of Sema5A in the regulation of NK and T cell immune responses. Methods: Recombinant Sema5A was used for the stimulation of Natural Killer (NK) and T cells. Intracellular signal transduction was assessed by Western Blot. Sema5A stimulated and non-stimulated NK or T cells were analyzed for receptor phenotype using flow cytometry. NK and T cell proliferation assays were performed in presence and absence of Sema5A protein. Cytokine secretion of NK cell populations in response to Sema5A was analyzed using Luminex technology. The capacity of Sema5A to modulate the cytotoxic potential of NK cells was measured in cytotoxic assays using K562 cells as targets. Results: Sema5A showed to induce the phosphorylation of ERK1/2 and Akt. Sema5A stimulation caused an increase of NKp44⫹ NK cells frequency by up to 94%. NKG2A⫹ and NKG2D⫹ NK cell population increased by up to 44% and 7% respectively. Upon Sema5A stimulation, the frequencies of CD25 and CD69 increased by up to 2.4 fold and 4.3 fold in NK cells, and by 2 fold and 9.5 fold in T cells, respectively. Stimulation with a combination of Sema5A, IL-2 plus IL-15 induced a significant increase by up to 67% and 59% in the proliferative capacity of NK cells and T cells, respectively. In NK cells, Sema5A was able to induce de novo production of IL-1 and GM-CSF, and to increase the secretion levels of IL-6, IL-8 and TNF␣ by 45-fold, 80-fold, and 1.8-fold, respectively. Furthermore, pre-incubation of NK cells with Sema5A increased their cytotoxic activity against K562 cells by up to 32%. Conclusions: These results show for the first time that Sema5A is a potent activator of NK cells and T cells. Thus, Sema5A and its pathway might be promising targets for the development of new therapeutic approaches against cancer.
104-P
Abstracts
SEMAPHORIN 5A ACTIVATES NK AND T CELL RESPONSES IN AN ANTIGEN-INDEPENDENT MANNER. Christiane Gras, Britta Eiz-Vesper, Stephan Immenschuh, Rainer Blasczyk, Constanca Figueiredo. Institute for Transfusion Medicine, Hannover Medical SChool, Hannover, Germany. Aim: Semaphorin 5A (Sema5A) was shown to be upregulated in cancer, however its function in the immune system is still unknown. We investigated the effect of Sema5A in the regulation of NK and T cell immune responses. Methods: Recombinant Sema5A was used for the stimulation of Natural Killer (NK) and T cells. Intracellular signal transduction was assessed by Western Blot. Sema5A stimulated and non-stimulated NK or T cells were analyzed for receptor phenotype using flow cytometry. NK and T cell proliferation assays were performed in presence and absence of Sema5A protein. Cytokine secretion of NK cell populations in response to Sema5A was analyzed using Luminex technology. The capacity of Sema5A to modulate the cytotoxic potential of NK cells was measured in cytotoxic assays using K562 cells as targets. Results: Sema5A showed to induce the phosphorylation of ERK1/2 and Akt. Sema5A stimulation caused an increase of NKp44⫹ NK cells frequency by up to 94%. NKG2A⫹ and NKG2D⫹ NK cell population increased by up to 44% and 7% respectively. Upon Sema5A stimulation, the frequencies of CD25 and CD69 increased by up to 2.4 fold and 4.3 fold in NK cells, and by 2 fold and 9.5 fold in T cells, respectively. Stimulation with a combination of Sema5A, IL-2 plus IL-15 induced a significant increase by up to 67% and 59% in the proliferative capacity of NK cells and T cells, respectively. In NK cells, Sema5A was able to induce de novo production of IL-1 and GM-CSF, and to increase the secretion levels of IL-6, IL-8 and TNF␣ by 45-fold, 80-fold, and 1.8-fold, respectively. Furthermore, pre-incubation of NK cells with Sema5A increased their cytotoxic activity against K562 cells by up to 32%. Conclusions: These results show for the first time that Sema5A is a potent activator of NK cells and T cells. Thus, Sema5A and its pathway might be promising targets for the development of new therapeutic approaches against cancer.