B and T Cell Epitopes of the Incursionary Foot-and-Mouth Disease Virus Serotype SAT2 for Vaccine Development

Figures

• 

  Figure 1. This simple schematic diagram shows the genome organization of FMDV, the encoded polyprotein, and matured proteins. It describes the long process of protein cleavage. The single ORF is illustrated in the box, and the viral proteins are named according to Rueckert and Wimmer’s nomenclature of picornavirus proteins [18]. Inside the boxes, there is a leader protein (L pro), four structural viral proteins (VP1-4), and seven non-structural proteins (2A-C, 3A-D). In addition, cleaved protein products and the cascade of cleavage are also shown in the diagram. The mature functional protein elements after cleavage are categorized as structural and non-structural proteins. The main cleavage sites are also shown in the box at the left side. The right and left untranslated regions (UTR) of the open reading frame are 3’ UTR and 5’ UTR respectively. The right extreme flank is shorter than the left one.

• 

  Figure 2. Incursionary features of FMDV serotype SAT2. In this map, SAT2 topotype VII was taken as an example. The directional arrows on the map show the epidemiological dynamics of SAT2 across different African regions, jumping the WOAH demarcated pools.

• 

  Figure 3. The illustration describes successive steps in epitope-based vaccine designing (this figure was adopted from Aryandra Arya and Sunil K Arora [103]. (1) In vitro antigenic epitope selection, identification, and analysis by using multiple immunoinformatic software from proteomic databases; (2) immunogenic B and T cell epitope selection by epitope insertion and sequence analysis; (3) synthesis of the designed neutralizing epitopes in the form of particulate, and evaluation of humoral and cellular immune responses by in vitro testing; (4) In vivo animal immunization to analyze the antibody responses to functionally characterize the anticipated neutralizing Abs- and cell-mediated immune responses.

• 

  Figure 4. Adjuvants targeting both innate and adaptive immunity and the mechanism action. (A) Innate immunity; molecular adjuvants (cytokines, chemokines, and dendritic stimulating molecules) incorporated as a gene in the same plasmid and, when co-delivered with the vaccine, can elicit efficient DC recruitment, activation, and Ag presentation to T cells. The CD8+ T lymphocytes are authorized by dendritic cells to become effector CTLs. For this, antigens need to be taken up, processed, and presented by dendritic cells (DCs) in association with MHC molecules. Cytokine adjuvants help sustain CD25+ regulatory T cells (T-regs) of the CD4+ cells. This can significantly improve the immune response. (B) Vaccine with adjuvants, such as oil-in-water emulsions and almunium hydroxide, can stimulate the adaptive arm of the immune system. The maturation of DCs are firstly recognized by CD4+ and CD8+ T cells. CD4+ T lymphocytes undergo a clonal expansion into two distinct T-helper subpopulations following contact with the MHC I-peptide complex. TH1 and TH2 cells stimulate the humoral and cell-mediated immune response through a different cytokine expression pattern. TLR4 agonists are considered to be the…