Influence of flanking sequences on the processing and presentation of a CD8+ cytotoxic T-cell epitope delivered by parvovirus-like particles

P. RUEDA; G. MORON; J. SARRASECA; C. LECLERC; J. I. CASAL

JOURNAL OF GENERAL VIROLOGY

SOC GENERAL MICROBIOLOGY

Año: 2004 vol. 85 p. 563 - 572

0022-1317

We have previously developed an antigen-delivery system based on hybrid recombinant porcineparvovirus-like particles (PPV-VLPs) formed by the self-assembly of the VP2 protein of PPVcarrying a foreign epitope at its N terminus. In this study, different constructs were made containinga CD8+ T-cell epitope of chicken ovalbumin (OVA) to analyse the influence of the sequenceinserted into VP2 on the correct processing of VLPs by antigen-presenting cells. We analysed thepresentation of the OVA epitope inserted without flanking sequences or with either differentnatural flanking sequences or with the natural flanking sequences of a CD8+ T-cell epitopefrom the lymphocytic choriomeningitis virus nucleoprotein, and as a dimer with or without linkersequences. All constructs were studied in terms of level of expression, assembly of VLPs and abilityto deliver the inserted epitope into the MHC I pathway. The presentation of the OVA epitopewas considerably improved by insertion of short natural flanking sequences, which indicated therelevance of the flanking sequences on the processing of PPV-VLPs. Only PPV-VLPs carryingtwo copies of the OVA epitope linked by two glycines were able to be properly processed,suggesting that the introduction of flexible residues between the two consecutive OVA epitopesmay be necessary for the correct presentation of these dimers by PPV-VLPs. These resultsprovide information to improve the insertion of epitopes into PPV-VLPs to facilitate their processingand presentation by MHC class I molecules