Methods for Evaluating Antigen-Specific Cytotoxic T Lymphocyte Frequency and Activity
Antigen-specific Cytotoxic T Lymphocytes (CTLs) can be detected by measuring responsiveness to major histocompatibility complex class I (MHC-I)-presented peptide as the ability to produce cytokines/chemokines or to eliminate target cells. Functional assays focus on measuring target cell elimination, similar to the 51 Cr release assay. These assays require the development or isolation of target cells that can be distinguished from the CTLs and can either support or mimic infection. Quantitative assays focus on identifying the frequency of antigen-specific CTLs through responsiveness to target cells or peptides. Intracellular cytokine staining assays like degranulation assays allow for enumeration of antigen-specific CTLs by response to a cognate ligand. In the degranulation assays, the percentage of CD8 + T cells that degranulate intracellular contents in response to an antigenic stimulus can be determined.
