de León, PatriciaCañas Arranz, RodrigoDefaus, SiraTorres, ElisaForner, Mar, 1980-Bustos, María J.Revilla, ConcepciónDomínguez, JavierAndreu Martínez, DavidBlanco, EstherSobrino, Francisco2021-03-252021-03-252021de León P, Cañas-Arranz R, Defaus S, Torres E, Forner M, Bustos MJ, Revilla C, Dominguez J, Andreu D, Blanco E, Sobrino F. Swine T-cells and specific antibodies evoked by peptide dendrimers displaying different FMDV T-cell epitopes. Front Immunol. 2021; 11:621537. DOI: 10.3389/fimmu.2020.6215371664-3224http://hdl.handle.net/10230/46930Dendrimeric peptide constructs based on a lysine core that comprises both B- and T-cell epitopes of foot-and-mouth disease virus (FMDV) have proven a successful strategy for the development of FMD vaccines. Specifically, B2T dendrimers displaying two copies of the major type O FMDV antigenic B-cell epitope located on the virus capsid [VP1 (140-158)], covalently linked to a heterotypic T-cell epitope from either non-structural protein 3A [3A (21-35)] or 3D [3D (56-70)], named B2T-3A and B2T-3D, respectively, elicit high levels of neutralizing antibodies (nAbs) and IFN-γ-producing cells in pigs. To assess whether the inclusion and orientation of T-3A and T-3D T-cell epitopes in a single molecule could modulate immunogenicity, dendrimers with T epitopes juxtaposed in both possible orientations, i.e., constructs B2TT-3A3D and B2TT-3D3A, were made and tested in pigs. Both dendrimers elicited high nAbs titers that broadly neutralized type O FMDVs, although B2TT-3D3A did not respond to boosting, and induced lower IgGs titers, in particular IgG2, than B2TT-3A3D. Pigs immunized with B2, a control dendrimer displaying two B-cell epitope copies and no T-cell epitope, gave no nABs, confirming T-3A and T-3D as T helper epitopes. The T-3D peptide was found to be an immunodominant, as it produced more IFN-γ expressing cells than T-3A in the in vitro recall assay. Besides, in pigs immunized with the different dendrimeric peptides, CD4+ T-cells were the major subset contributing to IFN-γ expression upon in vitro recall, and depletion of CD4+ cells from PBMCs abolished the production of this cytokine. Most CD4+IFN-γ+ cells showed a memory (CD4+2E3-) and a multifunctional phenotype, as they expressed both IFN-γ and TNF-α, suggesting that the peptides induced a potent Th1 pro-inflammatory response. Furthermore, not only the presence, but also the orientation of T-cell epitopes influenced the T-cell response, as B2TT-3D3A and B2 groups had fewer cells expressing both cytokines. These results help understand how B2T-type dendrimers triggers T-cell populations, highlighting their potential as next-generation FMD vaccines.application/pdfeng© 2021 de León, Cañas-Arranz, Defaus, Torres, Forner, Bustos, Revilla, Dominguez, Andreu, Blanco and Sobrino. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.info:eu-repo/semantics/articlehttp://dx.doi.org/10.3389/fimmu.2020.621537T cell phenotypeCytokineDendrimer peptideFoot-and-mouth disease virusVaccinesinfo:eu-repo/semantics/openAccess