Protection against Lymphocytic Choriomeningitis Virus Infection Induced by a Reduced Peptide Bond Analogue of the H-2Db-restricted CD8+ T Cell Epitope GP33

Abstract

Recent investigations have suggested that pseudopeptides containing modified peptide bonds might advantageously replace natural peptides in therapeutic strategies. We have generated eight reduced peptide bond ⌿(CH 2 -NH) analogues corresponding to the H-2D b -restricted CD8؉ T cell epitope (called GP33) of the glycoprotein of the lymphocytic choriomeningitis virus. One of these pseudopeptides, containing a reduced peptide bond between residues 6 and 7 (⌿(6 -7)), displayed very similar properties of binding to major histocompatibility complex (MHC) and recognition by T cell receptor transgenic T cells specific for GP33 when compared with the parent peptide. We assessed in vitro and in vivo the proteolytic resistance of GP33 and ⌿(6 -7) and analyzed its contribution to the priming properties of these peptides. The ⌿(6 -7) analogue exhibited a dramatically increased proteolytic resistance when compared with GP33, and we show for the first time that MHC-peptide complexes formed in vivo with a pseudopeptide display a sustained half-life compared with the complexes formed with the natural peptide. Furthermore, in contrast to immunizations with GP33, three injections of ⌿(6 -7) in saline induced significant antiviral protection in mice. The enhanced ability of ⌿(6 -7) to induce antiviral protection may result from the higher stability of the analogue and/or of the MHC-analogue complexes.T cells recognize antigenic peptides in association with MHC 1 molecules and play a key role in protection against harmful pathogens and in tumor elimination. Over the past years many attempts have been made to use synthetic peptides as potential vaccines and immunoregulatory agents (1, 2). Recent studies have provided evidence that pseudopeptides, in which one or several of the natural amide bonds (CO-NH) are replaced by CO-NH isosters (3), can have enhanced antigenic and immunogenic properties (4 -6). Most interestingly, it has been shown that such peptide analogues can bind to class I and II MHC molecules (7-13), and some of them also induce differential effects on T cell responsiveness (14) similar to those described with altered peptide ligands, which contain single amino acid replacements (15). These several recent studies thus demonstrated the potential interest of pseudopeptides as possible therapeutic strategies in T cell-mediated disorders.The high susceptibility of synthetic peptides to proteases is considered to be a major drawback for their use as vaccines or immunoregulatory molecules (16). We have previously shown that several pseudopeptides with enhanced antigenic activity are more resistant to proteolytic degradation in vitro (5, 6, 14, 17). However, no information on in vivo stability of such peptide analogues and the possible direct contribution of this resistance in their ability to modulate the immune response is available. Increased biological activity of protease-resistant pseudopeptide analogues has already been widely shown in other fields of medical chemistry (for review, see Ref. 18,[19][20][21][22]. The retro...

E-cadherin promotes accumulation of a unique memory CD8 T-cell population in murine salivary glands

“…This conclusion is further based on the finding that gp33 peptide-activated P14 T cells accumulated in SMG after adoptive transfer. As the gp33 peptide has a very short half-life in vivo (26), residual traces of gp33 peptides, possibly present in the transfer inoculum, would be degraded within minutes in the recipient mice. In addition, LCMV could not be detected in SMG by standard virus plaque assay either at the acute or at the stationary phase after low-dose systemic LCMV infection used here for generation of LCMV-immune mice.…”

Distinct Requirements for Deletion versus Anergy during CD8 T Cell Peripheral Tolerance In Vivo

“…A 200 g dose of soluble OVA peptide was shown to persist for 10 -14 days in vivo (14,41). In contrast, some lymphocytic choriomeningitis virus -derived peptides needed to be presented with adjuvants, such as IFA, to stimulate CD8 T cell responses (12), most likely because of their short half-life in vivo (40).…”

“…1). The kinetics of Ag presentation likely depend upon the characteristics of the individual peptide being examined (37)(38)(39)(40), as well as the avidity of the T cell clone. A 200 g dose of soluble OVA peptide was shown to persist for 10 -14 days in vivo (14,41).…”

Functional and Structural Characteristics of NY-ESO-1-related HLA A2-restricted Epitopes and the Design of a Novel Immunogenic Analogue

“…Several studies have incorporated nonnatural amino acids in peptidic structures to improve compound stability and maintain T cell cross-reactivity. For example, some studies have used nonnatural amino acids with modified side chains that approximate the natural amino acid (10,11) or by modifying peptide bonds by introducing ␤-amino acids (12,13), reducing peptide bonds from the natural amine bonds to aminomethylene (14,15) or generation of partially modified retro-inverso pseudopeptides (8,16,17).…”