PREPARATION AND IMMUNOLOGIC PROPERTIES OF STEREOSPECIFIC ALPHA-DINITROPHENYLNONALYSINES

α-N-Dinitrophenylnonalysine (L4DL4) was prepared by solid-phase synthesis (Merrifield, R. B. (1964), J. Org. Chem. 29, 3100; Biochemistry 3, 1385). By-products formed by partial cleavage of the ∈-N-benzyloxycarbonyl-protecting groups were detected and conditions for limiting their formation were investigated. Pure α-dinitrophenylnonalysine was obtained from the crude product by preparative ion-exchange chromatography. Digestion of the α-dinitrophenylnonalysine (L4DL4) with carboxypeptidase B yielded α-dinitrophenylhexalysine and lysine. Trypsin produced α-dinitrophenyltrilysine, dilysine, and tetralysine. In contrast, digestion of the α-dinitrophenylnona-L-lysine, the all-L stereoisomer, with carboxypeptidase B yielded α-dinitrophenyldilysine and lysine, whereas trypsin digestion produced α-dinitrophenyltrilysine, dilysine, and trilysine. α-Dinitrophenylnona-L-lysine, as previously reported (Schlossman, S. F., Yaron, A., Ben Efraim, S., and Sober, H. A. (1965), Biochemistry 4, 1638), was found to be immunogenic in guinea pigs of inbred strain 2 and in randombred Hartley strain. α-Dinitrophenylnonalysine (L4DL4), on the other hand, was completely devoid of the capacity to induce an immune response. Although nonimmunogenic, α-dinitrophenylnonalysine (L4DL4) provoked Arthus type but not delayed cross-reactions in animals sensitized to the all-L immunogenic isomer, suggesting that configuration of the oligolysine carrier is of major importance in determining the specificity of the delayed response, but not in hapten-specific antibody-dependent reactions. Thus, the substitution of one central L-lysine residue of α-dinitrophenylnona-L-lysine by the corresponding d residue leads to a major change in the immunologic behavior of this compound. These results suggest the participation of a stereospecific receptor for lysine oligopeptide conjugates both in the induction of the immune response and in the eliciting f the established cell-mediated delayed hypersensitivity reactions. © 1968, American Chemical Society. All rights reserved.