Dual-Color ELISPOT Assay for the Simultaneous Detection of IL-2 and/or IFN-γ Secreting T Cells

INTRODUCTION

The enzyme-linked immunospot (ELISPOT) assay measures the secretion intensity of effector molecules released by immune cells in response to ex vivo antigenic stimulation, as well as the frequency of these responding cells. This assay is highly sensitive, quantitative, easy to use, and amenable to high-throughput screening. For these reasons, the ELISPOT assay is considered by many as a gold standard for monitoring cellular immune responses. Until recently, ELISPOT assays using chromophores to detect the T cell secretion of cytokines were limited to the characterization of a single effector molecule. Notably, studies evaluating the immune response to chronic viral infections often measured IFN-γ secretion by ELISPOT because of the known antiviral effects of this cytokine as well as its correlation to the cytotoxic capacity of T cells. However, maintenance of both IFN-γ and IL-2 secretion by pathogen-specific T cells has been linked to a more favorable clinical outcome in human immunodeficiency virus (HIV) and Leishmania infections. Therefore, an ELISPOT assay able to simultaneously characterize T cell responses in terms of IL-2 and IFN-γ secretion is potentially relevant for the monitoring of immune responses to certain infectious agents. In this protocol, we describe an ELISPOT assay for the simultaneous detection of IL-2 and IFN-γ upon stimulation with viral peptides.