This present protocol is developed to analyze the frequency of IFN-γ-, IL-4- and IL-17-producing CD4+T cells, identified from ex vivo human peripheral blood mononuclear cells (PBMC). The frequencies of cytokine producing cells derived from activation of PBMC was induced trough the stimulus phorbol 12-myristate 13-acetate (PMA) and ionomycin. According onpreviously published protocols concentrations of stimulating substances were in the range from 10, to 50 ng/ml for PMA and 1 µg/ml for ionomycin (Gupta and Maecker, 2015; Foster et al., 2007; Freer and Rindi, 2013; https://www.bdbiosciences.com/content/bdb/paths/generate-tds-document.in.560751.pdf). The PMA concentrations of 10, 20 and 50 ng/ml were tested and finally the PMA concentration of 10 ng/ml was chosen since it was sufficient to obtain a frequency of cytokines comparable to that obtained with higher stimulus concentrations. PMA/ionomycin and brefeldin A are incubate together for a time of 5 h (Gupta and Maecker, 2015, Foster et al., 2007, Freer and Rindi, 2013, https://www.bdbiosciences.com/content/bdb/paths/generate-tds-document.in.560751.pdf). The protein secretion inhibitor brefeldin A, was used at the concentration of 10 µg/ml (Gupta and Maecker, 2015; Foster et al., 2007; Freer and Rindi, 2013). Cell concentrations may vary in a range from 2.5 x106 to 10 x106 cells/ml (Maecker, 2004; Freer and Rindi, 2013a; https://www.bdbiosciences.com/content/bdb/paths/generate-tds-document.in.560751.pdf). Concentration of 1x106 cells/ml, 4x106 cells/ml and 8x106cells/ml were tested. Cell tritation have shown a higher functional response proportional to the cell concentration when exposed to a fixed concentration of stimulants. Cell concentration of 8 milions/ml was selected in order to obtain the higher percentage of IFN-γ-, IL-4- and IL-17-producing CD4+T cells. In conclusion the present protocol provides that, for a optimal optimal percentage of IFN-γ-, IL-4- and IL-17-producing CD4+T cells as assessed by flow cytometry (Table 1), PBMC in a concentration 8 milions/ml were stimulated with PMA 10 ng/ml and ionomycin 1 µg/ml, and cultured for 5 h in presence of brefeldin A 10 µg/ml according to the procedure described in detail below. References Baran, J., Kowalczyk, D., Ozog, M., Zembala, M., 2001. Three-color flow cytometry detection of intracellular cytokines in peripheral blood mononuclear cells: Comparative analysis of phorbol myristate acetate-ionomycin and phytohemagglutinin stimulation. Clin. Diagn. Lab. Immunol. 8, 303–313. https://doi.org/10.1128/CDLI.8.2.303-313.2001 Foster, B., Prussin, C., Liu, F., Whitmire, J.K., Whitton, J.L., 2007. Detection of intracellular cytokines by flow cytometry. Curr. Protoc. Immunol. Chapter 6. https://doi.org/10.1002/0471142735.im0624s78 Freer, G., Rindi, L., 2013. Intracellular cytokine detection by fluorescence-activated flow cytometry: Basic principles and recent advances. Methods 61, 30–38. https://doi.org/10.1016/j.ymeth.2013.03.035 Gupta, S., Maecker, H., 2015. Intracellular Cytokine Staining (ICS) on Human Lymphocytes or Peripheral Blood Mononuclear Cells (PBMCs). BIO-PROTOCOL 5. https://doi.org/10.21769/bioprotoc.1442 Maecker, H.T., 2004. Cytokine flow cytometry. Methods Mol. Biol. 263, 95–108. https://doi.org/10.1385/1-59259-773-4:095 https://www.bdbiosciences.com/content/bdb/paths/generate-tds-document.us.560751.pdf BEFORE STARTING with this procedure Moreover, work under laminar flow hood when you are processing samples from the beginning to the end of the culture. Make sure you are using, sterile culture medium and sterile plastic disposable as well.
The Mycobacterium tuberculosis Early Secreted Antigenic Target of 6 kDa Inhibits T Cell Interferon-γ Production through the p38 Mitogen-activated Protein Kinase Pathway
