The invention provides compounds comprising at least one phosphoepoxide group of the formula: ##STR00001## where R1 is selected from among --CH.sub.3 and --CH.sub.2--CH.sub.3. Cat+ is an organic or inorganic cation, n is an integer between 2 and 20, processes for the production thereof and uses thereof, in particular therapeutic uses and for activating primate T.gamma.9.delta.2 lymphocytes.