The Journal of Immunology, Vol 155, Issue 9 4295-4306, Copyright © 1995 by American Association of Immunologists

ARTICLES

Molecular analysis of a heteroclitic T cell response to the immunodominant epitope of sperm whale myoglobin. Implications for peptide partial agonists

RD England, MC Kullberg, JL Cornette and JA Berzofsky
Molecular Immunogenetics and Vaccine Research Section, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.

We have investigated the molecular basis for binding and Ag presentation of an immunodominant Th cell determinant of sperm whale myoglobin, a prototype amphipathic helical structure in the native protein. A series of peptides with three different substitutions at each position were evaluated for binding to the class II MHC molecule I- Ad and for activation of two T cell clones with distinct fine specificity, to determine the role of each residue. The assignment of MHC binding and TCR binding residues is consistent with a peptide bound as a twisted beta-strand, with 130 degrees twist similar to that of the influenza hemagglutinin peptide crystallized in the groove of HLA-DR1. This twist gives the peptide amphipathicity, with a periodicity similar to an alpha-helix without its being a helix. Two substituted peptides were discovered to be heteroclitic, but by different molecular mechanisms, one involving gain of a favorable residue and one involving loss of an unfavorable one. Complexes of both peptides with I-Ad had enormously higher affinity for the TCR, but peptide affinity for the MHC molecule was not increased, such that the wild-type peptide acted as a partial agonist and inhibited the response to the heteroclitic ones. Moreover, the magnitude of response was elevated in a way that could not be mimicked by the wild-type peptide even at higher concentration. These results suggest a TCR dwell time requirement for optimal signal transduction that may help explain the mechanism of partial agonism.

This article has been cited by other articles:

				K. Ogata, A. Jaramillo, W. Cohen, J.-P. Briand, F. Connan, J. Choppin, S. Muller, and S. J. Wodak Automatic Sequence Design of Major Histocompatibility Complex Class I Binding Peptides Impairing CD8+ T Cell Recognition J. Biol. Chem., January 3, 2003; 278(2): 1281 - 1290. [Abstract] [Full Text] [PDF]

				S. K. Joshi, P. R. Suresh, and V. S. Chauhan Flexibility in MHC and TCR Recognition: Degenerate Specificity at the T Cell Level in the Recognition of Promiscuous Th Epitopes Exhibiting No Primary Sequence Homology J. Immunol., June 1, 2001; 166(11): 6693 - 6703. [Abstract] [Full Text] [PDF]

				J. M. Robertson, P. E. Jensen, and B. D. Evavold DO11.10 and OT-II T Cells Recognize a C-Terminal Ovalbumin 323-339 Epitope J. Immunol., May 1, 2000; 164(9): 4706 - 4712. [Abstract] [Full Text] [PDF]

				R. Dyall, W. B. Bowne, L. W. Weber, J. LeMaoult, P. Szabo, Y. Moroi, G. Piskun, J. J. Lewis, A. N. Houghton, and J. Nikolic-Zugic Heteroclitic Immunization Induces Tumor Immunity J. Exp. Med., November 2, 1998; 188(9): 1553 - 1561. [Abstract] [Full Text] [PDF]

				G. R. Leggatt, A. Hosmalin, C. D. Pendleton, A. Kumar, S. Hoffman, and J. A. Berzofsky The Importance of Pairwise Interactions Between Peptide Residues in the Delineation of TCR Specificity J. Immunol., November 1, 1998; 161(9): 4728 - 4735. [Abstract] [Full Text] [PDF]

				U. Zugel, R. Wang, G. Shih, A. Sette, J. Alexander, and H. M. Grey Termination of Peripheral Tolerance to a T Cell Epitope by Heteroclitic Antigen Analogues J. Immunol., August 15, 1998; 161(4): 1705 - 1709. [Abstract] [Full Text] [PDF]

				J. D. Ahlers, T. Takeshita, C. D. Pendleton, and J. A. Berzofsky Enhanced immunogenicity of HIV-1 vaccine construct by modification of the native peptide sequence PNAS, September 30, 1997; 94(20): 10856 - 10861. [Abstract] [Full Text] [PDF]

				B. M. Kessler, P. Bassanini, J.-C. Cerottini, and I. F. Luescher Effects of Epitope Modification on T Cell Receptor-Ligand Binding and Antigen Recognition by Seven H-2Kd-restricted Cytotoxic T Lymphocyte Clones Specific for a Photoreactive Peptide Derivative J. Exp. Med., February 17, 1997; 185(4): 629 - 640. [Abstract] [Full Text] [PDF]