Abstract: The peptides of formula IA--x--Lys--y--B Iin which:A is H, a tripeptide of formula Arg-Ala-Arg or an hexapeptide of formula Glu-Lys-Arg-Arg-Ala-Arg x and y, different one from the other, are an arginine (Arg) or a glutamic acid (Glu) residue;B is OH or a tripeptide Arg-Ala-Arg with the proviso that when A is hydrogen and x is ARg, B is different from OH comprising the steps of:a) binding the Boc-protected carboxyterminal aminoacid to a suitable resin;b) reacting the other Boc-protected aminoacids with the resin-bound carboxyterminal aminoacid in the desired sequence;c) removing the protecting groups and releasing the so obtained peptides from the resin,have valuable pharmacological properties as immunostimulating agents.

Abstract: The present invention is referred to tripeptides having the following general formula:X-Gly-Ywhere X=L-Arg or D-Arg and Y=L-Asp or D-Asp.These tripeptides, endowed with both immunostimulant and antimetastatic properties, are active not only after parenteral administration, but also after oral treatment.The invention is also related to the procedure for the preparation of said compounds.

Abstract: The tripeptide Arg-Lys-Glu, synthetized by conventional solution methods, and its salts display immunostimulating activity both on maturation of immature T cells and on T cell function.

Abstract: Compounds of general formula (I) ##STR1## wherein: m is zero or 1;n is zero, 1, 2, 3 or 4;A is a 3,7-dimethylxanthine-1-yl or 1,3-dimethylxanthine-7-yl residue;show marked anti-platelet activity.