Quantification of antigen specific CD8+ T cells using an ELISPOT assay

Area of Science:

• Immunology
• Cellular immunology
• T cell assays

Background:

• CD8+ T cells play a crucial role in adaptive immunity, particularly in response to viral infections and tumors.
• Quantifying antigen-specific CD8+ T cells is essential for understanding immune responses and developing effective vaccines.
• Existing methods for enumerating antigen-specific CD8+ T cells can be complex, time-consuming, or lack sensitivity.

Purpose of the Study:

• To standardize and validate an ELISPOT assay for the detection and enumeration of antigen-specific CD8+ T cells.
• To define optimal conditions for the assay, including antigen concentration, antigen-presenting cells, and growth factors.
• To compare the sensitivity and efficiency of the ELISPOT assay with other established methods.

Main Methods:

• Standardization of an Enzyme-Linked ImmunoSpot (ELISPOT) assay using cloned murine CD8+ T cells specific for a malaria antigen epitope.
• Detection of interferon-gamma (IFN-γ) secretion by single cells upon antigen stimulation.
• Optimization of culture conditions and definition of necessary reagents for assay performance.

Main Results:

• The ELISPOT assay demonstrated high sensitivity, detecting 80-95% of known cloned CD8+ T cells.
• Optimal culture conditions, antigen concentrations, and cell numbers were defined for reliable assay performance.
• The assay successfully quantified antigen-specific CD8+ T cells in spleen cell populations from immunized mice.

Conclusions:

• The developed ELISPOT assay provides a sensitive, precise, and efficient method for enumerating antigen-specific CD8+ T cells.
• This assay is simpler and more sensitive than traditional chromium-51 release assays and precursor frequency analysis.
• The assay is valuable for analyzing immune responses in mixed lymphocyte populations and for vaccine development research.