Intracellular CD154 Expression Reflects Antigen-specific CD8+ T Cells butShows Less Sensitivity than Intracellular Cytokine and MHC TetramerStaining

A recent report showed that analysis of CD154expression in the presence of the secretion inhibitor BrefeldinA (Bref A) could be used to asses the entire repertoire ofantigen-specific CD4+ T helper cells. However, the capacityof intracellular CD154 expresion to identify antigen-specificCD8+ T cells has yet to be investigated. In this study, wecompared the ability of intracellular CD154 expression toassess antigen-specific CD8+ T cels with that of acceptedstandard assays, namely intracellular cytokine IFN-γ staining(ICS) and MHC class I tetramer staining. The detection ofintracellular CD154 molecules in the presence of Bref Areflected the kinetic trend of antigen-specific CD8+ T celnumber, but unfortunately showed les sensitivity than ICSand tetramer staining. However, ICS levels peaked andBref A and then declined, whereas intracellular CD154expression peaked by 8 h and maintained the saturated levelup to 24 h post-stimulation. Moreover, intracelular CD154expression in antigen-specific CD8+ T cels developed inthe absence of CD4+ T cels changed little, whereas thenumber of IFN-γ-producing CD8+ T cells decreased abruptly.These results suggest that intracellular CD154 could aid theassessment of antigen-specific CD8+ T cells, but does not+ T helpercells. Therefore, the combined analytical techniques of ICSand tetramer staining together with intracellular CD154asays may be able to provide useful information on theacurate phenotype and functionality of antigen-specificCD8+ T cels. KCI Citation Count: 0