Simultaneous Identification of Functional Antigen-Specific CD8+ and CD4+ Cells after In Vitro Expansion Using Elongated Peptides
J. Schuhmacher, Leon Kleemann, Jennifer R. Richardson, Elisa Rusch, Hans‐Georg Rammensee, Cécile Gouttefangeas
Abstract
Elongated peptides (EPs), containing possibly one or multiple epitope/s, are increasingly used for the screening of antigen-specific CD8+ and CD4+ cell responses. Here, we present an in vitro protocol that allows the amplification of antigen-specific cells and the subsequent functional analysis of both T cell types using EPs. Known viral-derived epitopes were elongated to 20 mer EPs on the N-, C-, and both termini for HLA class I binders, or on the N- and C- termini for HLA class II binders. With EP stimulation only, the percentage of responding CD8+ T cells was dependent on the elongation site of the EP, whereas CD4+ T cell responses were completely lost in 22% of the tests performed ex vivo. A short-term amplification step plus the addition of a TLR3 agonist (Poly-ICLC) together with an increased EP concentration improved markedly the detection of CD8+ and CD4+ T cell reactivities.