Fluorescent antigen-transfected target cell cytotoxic T lymphocyte assay for ex vivo detection of antigen-specific cell-mediated cytotoxicity

van Baalen CA, Kwa D, Verschuren EJ, Reedijk ML, Boon AC, de Mutsert G, Rimmelzwaan GF, Osterhaus AD and Gruters RA
Source: J Infect Dis
Publication Date: (2005)
Issue: 192(7): 1183-1190
Research Area:
Immunotherapy / Hematology
Cells used in publication:
Species: human
Tissue Origin: blood
PBMC, human
Species: human
Tissue Origin: blood
Species: human
Tissue Origin: blood
Nucleofectorâ„¢ I/II/2b
Transfected vectors expressing HIV and influenza genes as GFP fusions. Used transfected cells as targets for fluorescent antigen-transfected target cell-CTL assays and compared results with standard Chromium release assay.
Ex vivo detection of virus-specific cytotoxic T lymphocyte (CTL) responses is limited to the use of methods assessing cytokine production, degranulation, or perforin contents of antigen-specific CD8(+) T cells. Generally, their cytotoxic activity is detectable only after cultivation. We describe the fluorescent antigen-transfected target cell-CTL (FATT-CTL) assay, which measures antigen-specific cytotoxicity ex vivo. Target cells were generated by nucleofection with DNA vectors encoding antigen-green fluorescent protein (GFP) fusion proteins. After coculture at various effector : target (E : T) cell ratios, viable and dead GFP-positive cells were quantified by flow cytometry, and antigen-specific target-cell elimination was calculated. The assay was validated with human immunodeficiency virus (HIV)- and influenza virus-specific CTL clones and revealed cytotoxicity at lower E : T cell ratios than standard (51)Cr-release assays. Moreover, antigen-specific cytotoxicity was detected ex vivo within 1 day in peripheral blood mononuclear cells from HIV-infected individuals. The FATT-CTL assay provides a versatile tool that will advance our understanding of cell-mediated immunity.