Fig. 4.

Multiple amino acid sequence alignment of nine Tp2 antigen variants detected in 96 T. parva samples from DRC and Burundi. Amino acids are denoted by the single-letter codes. Var-1 to var-59 are variant names. The antigen variants nomenclature used in this study was first initiated by Pelle et al. [36]. Antigen variants var-1 and var-2 were described in Pelle et al. [36] and Salih et al. [37] and are, respectively, Muguga (identical to Serengeti-transformed) and Kiambu-5 strains. Reference sequences component of the Muguga cocktail live vaccine are represented by Muguga (GenBank: JF451856), Serengeti (Serengeti-transformed, GenBank: JF451862) and Kiambu-5 (GenBank: JF451880). The numbers in square brackets behind variants names indicate the number of T. parva samples represented by each variant. The six previously described epitopes (epitope1-6), that are the target of the bovine CD8⁺ T cells immune responses are bolded and boxed. The conserved amino acid residues in the epitopes are coloured in red. The star (*) below the alignment indicates positions of conserved amino acid residues. The shaded and boxed flanked regions denote the inner primers used for sequencing. Tp2 Antigen variants var-1 and var-2 are found in Muguga/Serengeti and Kiambu-5 strains, respectively. Corresponding gene alleles and sample characteristics are presented in Additional file 3: Table S3