Synthetic immunoadjuvant corresponding to the smallest immunologically active glycopeptide subunit of the bacterial cell wall. Prepn: A. Adam et al., DE 2450355; eidem, US 4235771 (1975, 1980 both to Agen. Nat. Valor. Recher.); C. Merser et al., Biochem. Biophys. Res. Commun. 66, 1316 (1975); P. Lefrancier et al., Int. J. Pept. Protein Res. 9, 249 (1977). Structure-activity relationships: F. Ellouz et al., Biochem. Biophys. Res. Commun. 59, 1317 (1974); A. Adam et al., ibid. 72, 339 (1976). Review of immunoregulating activity: L. Chedid et al., Prog. Allergy 25, 63-105 (1978). Tissue distribution in mice: M. Parant et al., Int. J. Immunopharmacol. 1, 35 (1979). Potentiation of antitumor immunity: S. Sone et al., J. Biol. Response Modif. 3, 185 (1984); A. E. Eggers, ibid. 7, 229 (1988).