Synthesis and immunological properties of the oligolysyl-N^iε-dinitrophenyllysine and oligolysylalanylalanylalanyl-N^iε-dinitrophenyllysine peptide series

Abstract

A new series of 2,4-dinitrophenyllysyl oligopeptides containing a trialanyl sequence was prepared for investigation of the minimal size requirements and influence of charge density on immunogenicity and the specificity of the immune response to those defined antigens. The Lys,-Alas-N'-DnpLys series of peptides was synthesized by: (1) stepwise synthesis of the tetrapeptide P la3-N'-Dnp-Lys benzyl ester ;(2) polymerization of Ne-Z-Lys-N-carboxyanhydride using the above tetrapeptide as the initiator; (3) removal of protecting groups; and (4) fractionation of the resulting Lys,-Ala3-N'-Dnp-Lys series into its individual components by ion exchange chromatography. All inbred strain 2 guinea pigs, when immunized with the unfractionated Lys,-Alas-N'-DnpLys (a = lo), Lysc-Ala,-N'-Dnp-Lys, or Lys7-Alar-W-DnpLys, responded by the development of delayed hypersensi-S ynthetic polypeptide antigens of defined chemical structure have been useful tools of immunochemical investigation (Sela, 1970). The dinitrophenyl (Dnp)-oligolysinel system has afforded a means of studying the chemical requirements for immunogenicity as well as the specificity of antibody and of cell-mediated immunologic reactions Paul et ai., 1970;Schlossman, 1972). It was established that the minimal chain length required for immunogenicity of polylysine and Dnp-oligolysines in guinea pigs is seven Llysine residues . We wanted now to find out whether it is possible to replace some of the lysines by other amino acid residues such as alanine. A series of oligopeptides of the general chemical structure of Lys,-Ala3-Nf-Dnp-Lys was prepared. These immunogens consist of an oligolysine part of varying chain length n and of a constant part Alas-N'-Dnp-Lys. The trialanyl sequence separates the oligolysine carrier from the Dnp-lysine hapten.It was expected that if a sequence of seven lysine residues is a prerequisite for immunogenicity, the smallest member of the series to be found immunogenic will be Lys7-Ala3-NC-Dnp-Lys.If, however, one, two, or three of the lysine residues can be

Nature of T lymphocyte recognition of macrophage-associated antigens. V. Contribution of individual peptide residues of human fibrinopeptide B to T lymphocyte responses.

“…Thus, the peptide analogues tested thus far indicate that it is possible to alter completely the specificity of the strain 2 clonal T cell response while preserving genetic control. Schlossman et al reached a similar conclusion based on their elegant studies of cellular immune responses in guinea pigs to dinitrophenyl (DNP)-oligolysine antigens (28)(29)(30)(31). In these studies, strain 2 animals responded to antigens as small as DNP-heptalysine and could distinguish between the length of the DNP-oligolysines antigens as well as the position of the DNP hapten.…”

Role of MHC Gene Products in Immune Regulation

“…sequences critical for immunogenicity may provide some indication of the size of the postulated site of interaction with the la molecules. The studies of Schlossman and associates (95,96) on the immunogenicity of DNP-oligo-L-lysines for strain 2 guinea pigs is very informative. The smallest oligolysine polymer which is immunogenic has seven lysines.…”

Persistence of influenza as an immunogen in pulmonary antigen-presenting cells

“…Thus, some of the inoculated virus persisted in the lung within cells, and the viral protein was of sufficient size to be immunogenic. TCA precipitability suggests the presence of a peptide greater than 3,000 molecular weight, and heptapeptides have been shown to be immunogenic in guinea pigs (40). A measureable amount of potentially immunogenic virus was also present in HLN (Table 1).…”

“…Therefore, the percent cell-associated radioactivity was determined as the counts per minute in the cell pellet divided by the counts per minute in the whole organ and represented the minimal amount of radioactive virus in the cells. Protein precipitation with 10% TCA was performed on both the cell and supernate fractions to determine the percentage of radioactivity in peptides of >3,000 molecular weight and, therefore, of sufficient size to be potentially immunogenic in guinea pigs (40).…”