Antigen derivatives and processes for their preparation

A novel antigen derivative, which comprises an antigen radical and one or more muramylpeptide radicals covalently bound thereto, directly or via a spacer, the antigen and muramylpeptide of those radicals each containing at least one functional group characterized in that upon reaction between antigen and muramylpeptide, antigen and spacer or muramylpeptide and spacer one of the below-mentioned covalent linking-structures is formed between the reactants, said muramylpeptide has the formula ##STR10## in which X is a carbonyl, carbonyloxy or sulfonyl group, R.sub.1, R.sub.4 and R.sub.6 independently of one another represent hydrogen, alkyl having from 1 to 18 carbon atoms, benzyl which is unsubstituted or substituted in the aromatic nucleus by lower alkyl, hydroxyl, lower alkoxy, lower alkylenedioxy, mercapto, lower alkylmercapto, trifluoromethyl and/or halogen, or represent alkanoyl having from 2 to 18 carbon atoms, benzoyl or naphthoyl which are unsubstituted or substituted by halogen, lower alkyl, lower alkoxy, trifluoromethyl, hydroxyl or lower alkanoyloxy, or represent an acyl radical of a lower alkanesulfonic acid

• or of phenylsulfonic acid, which is unsubstituted or substituted by lower alkyl or halogen, or represent carbamoyl, lower alkyl-carbamoyl or phenyl-carbamoyl, R.sub.2 represents alkyl having 1 to 18 carbon atoms which is unsubstituted or substituted by hydroxy, lower alkoxy, lower alkanoyloxy, halogen, mercapto, lower alkylmercapto, lower alkanoylmercapto, carboxy, lower alkoxycarbonyl and/or carbamoyl, or represents phenyl which is unsubstituted or substituted by lower alkyl, hydroxy, lower alkoxy, lower alkanoyl, lower alkylenedioxy, halogen and/or trifluoromethyl, R.sub.3, R.sub.7, R.sub.9 and R.sub.13 are independently of one another hydrogen or lower alkyl, R.sub.8 is hydrogen, lower alkyl which is unsubstituted or substituted by hydroxy, lower alkoxy, lower alkanoyloxy, mercapto, lower alkylmercapto, lower alkanoylmercapto, amino, lower alkanoylamino, carbamoylamino or cycloalkyl having 5 or 6 carbon atoms, or represents cycloalkyl-lower alkyl, the cycloalkyl radical of which contains 5 or 6 carbon atoms, phenyl or phenyl-lower alkyl, in which the phenyl radicals are unsubstituted or substituted as defined above, or heterocyclic radicals are 5- or 6-membered, contain one or two nitrogen atoms in the ring and may or may not contain a fused phenyl radical, R.sub.7 and R.sub.8 together can also represent alkylene having 3 or 4 carbon atoms, R.sub.10, R.sub.11 and R.sub.12 independently of one another represent carboxyl, lower alkoxycarbonyl or carbamoyl which is unsubstituted or mono- or disubstituted at the nitrogen atom by unsubstituted or carboxy- or carbamoyl-substituted lower alkyl or by phenyl, benzyl, tetramethylene or pentamethylene and R.sub.11 can also be hydrogen, with the proviso that the muramylpeptide and the antigen are bonded together via the covalent linking structures carbonyloxy ##STR11## carbonylimino ##STR12## wherein R is hydrogen or lower alkyl), carbonylthio ##STR13## thiocarbonyloxy ##STR14## and/or thiocarbonylimino ##STR15## wherein R' is hydrogen or lower alkyl) directly or via a spacer, and with the further proviso that the antigen-muramylpeptide derivative may or may not be fixed to a high molecular weight carrier and that the antigen is not a constituent of a vaccine against tumour cells.