Methods of therapy effective for various cancers, immune deficiency diseases and infections, and methods of proliferation/activation of cells associated therewith, performed at costs such as those applicable to nonhuman animals. There is provided a method of proliferation/activation, comprising, in the stage of cell culture, adding a plant lectin, such as concanavalin A, and a growth factor having interleukin 2-like activity to the medium. Accordingly, αβ-type T cells associated with cellular immune for cancers, immune deficiency diseases and infections can be proliferated/activated on a preferential basis.
