METHOD FOR DETECTING REGULATORY T CELLS USING EXPRESSION OF FOLATE RECEPTOR 4 AS INDICATOR, METHOD FOR TREATING DISEASES USING THE DETECTION METHOD, PHARMACEUTICAL COMPOSITION FOR IMMUNOSTIMULATION, AND METHOD FOR TREATING DISEASES USING THE COMPOSITION
An object of the present invention is to provide a technique to distinguish between Treg cells and activated T cells in a live state. Another object of the present invention is to provide a pharmaceutical composition for immunostimulation that can reduce the number of Treg cells in vivo and effectively express the immune response of activated T cells.In the method of the present invention, Treg cells are detected from test cells containing (i) regulatory T cells and (ii) at least one type of cell selected from the group consisting of naive T cells and activated T cells, wherein expressions of folate receptor 4 on the surfaces of cells are measured and Treg cells are detected using the expressions as an indicator. The present invention uses anti-folate receptor 4 antibody or folate receptor 4-binding fragment as an active ingredient contained in a pharmaceutical composition for immunostimulation.