Identification of swine influenza virus epitopes and analysis of multiple specificities expressed by cytotoxic T cell subsets

Abstract

BackgroundMajor histocompatibility complex (MHC) class I peptide binding and presentation are essential for antigen-specific activation of cytotoxic T lymphocytes (CTLs) and swine MHC class I molecules, also termed swine leukocyte antigens (SLA), thus play a crucial role in the process that leads to elimination of viruses such as swine influenza virus (SwIV). This study describes the identification of SLA-presented peptide epitopes that are targets for a swine CTL response, and further analyses multiple specificities expressed by SwIV activated CTL subsets.FindingsFour SwIV derived peptides were identified as T cell epitopes using fluorescent influenza:SLA tetramers. In addition, multiple CTL specificities were analyzed using peptide sequence substitutions in two of the four epitope candidates analyzed. Interestingly both conserved and substituted peptides were found to stain the CD4-CD8+ T cell subsets indicating multiple specificities.ConclusionsThis study describes a timely and cost-effective approach for viral epitope identification in livestock animals. Analysis of T cell subsets showed multiple specificities suggesting SLA-bound epitope recognition of different conformations.

T‐cell epitope content comparison (EpiCC) of swine H1 influenza A virus hemagglutinin

“…We have previously identified highly conserved SLA‐restricted epitopes in the NA and M proteins that are found in different IAV subtypes . Other groups have also reported conserved SLA class I‐restricted epitopes in NA . This EpiCC analysis focuses on HA (while disregarding conserved internal and other external genes), as much of the antigenic variability between IAV strains circulating in swine (and differences in protection by vaccine strains) is localized to the HA surface antigen.…”

Identification of cross-reacting T-cell epitopes in structural and non-structural proteins of swine and pandemic H1N1 influenza A virus strains in pigs

“…However, it is noteworthy that SpH1N1-HA-specific T-cells (Tets 66 and 93) were detected after pdmH1N1 infection, indicating that a population of T-cells was primed after the second infection, which cross-reacted. A previous study in pigs suggested that there is flexibility in T-cell receptor recognition of class I epitopes and thus they can recognize non-homologous peptides [5]. It could also be speculated that HA-SpH1N1-specific T-cells, generated during the first infection, were re-activated by pdmH1N1 in a non-specific or bystander way, as has been described for other systems [17].…”

“…Previously, a combination of different bioinformatics prediction methods and in vitro testing has been used to identify T-cell epitopes in pigs [5]. In addition, recent approaches that use immunoinformatic tools have been used to identify MHC class I and class II T-cell epitopes that are highly conserved in SwIVs circulating in the US swine population [6].…”

“…PE-conjugated MAb against porcine CD8a (clone 76-2-11, BD Pharmingen) and FITC-conjugated MAb against porcine CD3" (clone PPT3, Southern Biolegend) were additionally used to characterize cells that stained positive with the tetramers. CD3 + CD8 high cells contain a CD8 + ab T-cell subpopulation which recognises class-I epitopes [5,15] high ranged from 0.4 to 2.6 %, depending on individual peptides and animals ( Table 2). Nine peptides were identified as T-cell epitopes by tetramer staining; three located in the M1 protein (Tet62, Tet56 and Tet64), three in NA (Tet55, Tet60 and Tet59) and three in HA (Tet93, Tet57 and Tet66).…”

Effectiveness evaluation of dendritic cell immunotherapy for osteosarcoma on survival rate and in vitro immune response

“…Recently, tumor immunotherapy based on DCs has gained credence for clinical practice, as DCs have been demonstrated to protect animals from immune attack in addition to the induction of a specific proliferation response (Li et al, 2014b). In clinical application, DCs-derived vaccines have elicited satisfactory effects in treating breast, colorectal, and lung cancers (Patch et al, 2013;Pedersen et al, 2014).…”