Abstract: Disclosed is a method for detecting an antigen-specific activated T cell comprising: acquiring first information on a particle size and second information on a T cell activation marker for a first measurement sample prepared by mixing in vitro a first specimen separated from a biological sample containing a T cell and an antigen-presenting cell and an antigen reagent containing a predetermined antigen, by measuring the first measurement sample with a flow cytometer; acquiring the first information and the second information for a second measurement sample prepared from a second specimen separated from the biological sample and not containing the antigen reagent, by measuring the second measurement sample with the flow cytometer; detecting a target particle in the first measurement sample based on the first information and the second information on the first measurement sample, and detecting a background particle in the second measurement sample based on the first information and the second information on the

Abstract: A novel use of agonist to PD-1 is developed. Provided is a pharmaceutical composition for treating or preventing Th2-mediated diseases, the composition comprising an effective amount of a PD-1 agonist.