A method for activating human antigen presenting cells characterized by culturing in vitro antigen presenting cells with a human origin together with at least one of glycoside compounds represented by general formula (A) or salts thereof preferably exemplified by (2S, 3S, 4R)-1-(α-D-galactopyranosyloxy)-2-hexacosanoylamino-3,4-octadecanediol; the human antigen presenting cells thus activated; methods for treating cancer or infectious diseases such as AIDS by using activated human antigen presenting cells; and the use of activated human antigen presenting cells in the production of drugs for treating these diseases. Thus, sufficient therapeutic effects can be achieved on cancer and infectious diseases such as AIDS without effecting any pulse therapy with the use of tumor antigens.