Characterizing T-cell epitopes of pathogens that cause localized infections such as human papillomavirus is a challenge because of limited number of T cells in circulation. A method is described in which rare T cells were isolated and were characterized starting with a very small number of cells.
Wang, X., Greenfield, W. W., Coleman, H. N., James, L. E., Nakagawa, M. Use of Interferon-γ Enzyme-linked Immunospot Assay to Characterize Novel T-cell Epitopes of Human Papillomavirus. J. Vis. Exp. (61), e3657, doi:10.3791/3657 (2012).