Figure 1

Antigens, immunization schedule and analysis of the immune sera. (A) Schematic presentation of the viral envelope proteins and antigens used for immunization. (a) Precursor envelope protein of PERV-A (numbering according accession number AJ133817), protease cleavage sites (PCS) are marked with arrow heads, SP - signal peptide. R - R peptide. (b) Recombinant gp70 as expressed using vector pET22b(+) with an N-terminal pelB leader sequence promoting translocation to the periplasma and a C-terminal His-tag. (c) Recombinant p15E with N-terminal fused calmodulin binding protein (CBP) as expressed using the vector pCal-n. (B) Immunization schedule indicating the time of immunization and bleedings. (C) SDS-PAGE of the purified p15E (12 kDa) and (D) gp70 (54 kDa) and Western blot analyses of the immune sera using p15 (C) and gp70 (D) used for immunization. The fragile gp70 showed smaller molecules due to proteolysis. Lane 1 – marker proteins (not shown in D), lane 2 – purified p15E (C) or gp70 (D), lane 3–7, sera from animals immunized with p15E, one serum was tested twice, lane 8–9, sera from animals immunized with gp70, lane 12–15, sera from animals immunized with p15E and gp70, lane 16–19, sera from control animals immunized with adjuvant.