Test Catalog

Test ID: GLICP    
CD8 T-Cell Immune Competence Panel, Global, Whole Blood

Method Description Describes how the test is performed and provides a method-specific reference

CD8 T-Cell Immune Competence, Global:

Peripheral blood mononuclear cells (PBMCs), which contain CD8 T cells, are stimulated with a mixture of phorbol myristate acetate and ionomycin, and with stimulatory signals derived using antibodies against the costimulatory molecules CD28/CD49d. The cells are simultaneously treated with a mixture of brefeldin A and monensin, which blocks extracellular secretion of interferon-gamma (IFN-gamma), enabling intracellular retention and detection of the protein. PBMCs that have not been stimulated are used as a control to determine the background levels of IFN-gamma and CD107a and CD107b. The cells are analyzed on the Becton Dickinson FACS Canto flow cytometer and analysis involves gating (defining) of the CD8 T cells using an antihuman CD8 antibody. Specific IFN-gamma and CD107a and CD107b signals are determined within the "gated" CD8 T-cell population. Global CD8 T-cell immune competence is measured by the amount of IFN-gamma produced (CD8 T-cell functional activity) and surface expression of CD107a and CD107b (cytoxicity assessment) relative to the unstimulated control and is interpreted on the basis of the reference range determined from healthy adult donors.(Unpublished Mayo method)


Quantitative Lymphocyte Subsets: T, B, and NK:

The T, B, and NK-cell surface marker assay uses monoclonal antibodies to identify the various membrane antigens, and flow cytometry to enumerate the number of cells expressing these differentiation antigens. CD14 is used to exclude monocytes, thereby improving accuracy and enhancing the purity of the lymphocyte population. The results are reported as the percent of lymphocytes that are total T cells (CD3+), CD3+CD4+ T cells, CD3+CD8+ T cells, natural killer (CD16+56+, CD3-), and B-lymphocytes (CD19+), and the absolute number of each cell type per mL of blood. The assay is a 7-color no-wash procedure and the absolute counts are calculated from internal bead standards. In addition, the total lymphocyte count and the CD4:CD8 ratio are reported.(Hoffman RA, Kung PC, Hansen WP, Goedstien G: Simple and rapid measurement of human T lymphocytes and their subclasses in peripheral blood. Proc Natl Acad Sci USA, 1980:77:4914-4917; US Department of Health and Human Services: Guidelines for performance of CD4+ T-cell determinations in persons with human immunodeficiency virus infection. MMWR Morb Mortal Wkly Rep 1997;46 no. RR-2 pp 1-29)

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

3 to 6 days

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

EDTA whole blood: 4 days; PBMC's: 7 days

Performing Laboratory Location Indicates the location of the laboratory that performs the test