Antigenic Properties of Open Reading Frame 2 protein of Porcine Circovirus Type 2 from Vaccines Extracted by Ultrafiltration Method

Abstract

The purpose of this study was to determine the feasibility of extracting Open reading frame 2 (ORF2) protein from subunit vaccine against Porcine Circovirus type 2 infection, for the propose using as antigen for immunological testing. Proteins were extracted from vaccines by ultrafiltration from four manufacturers: Vaccine A: contains at least 200 mcg of ORF2 protein and 4 mg of carbomer per 1 ml. Vaccine B: contains 100 mcg of ORF2 protein and 2 mg of Aluminium hydroxide per 1 ml. Vaccine C: contains at least 1 RP. of ORF2 protein and 1 mg of carbomer per ml. Vaccine D: contains at least 1 RP. of ORF2 protein and oil in water emulsion per 2 ml. Total extracted proteins were assayed by gel electrophoresis using Native Polyacrylamide and Sodium Dodecyl Sulfate- Polyacrylamide methods. Then the total proteins were examined by Bradford method. Finally, the extracted proteins from suitable vaccine were further examined for their antigenic properties using dot blot and Enzyme-Linked Immunosorbent Assay (ELISA). The results revealed that the extracted ORF2 protein from vaccine B is suitable for use in immunological testing. The ORF2 protein which included in total extracted proteins solution able to bind to high immune level positive control serum against PCV2 by dot blot method as well as ELISA test. The difference between the positive and negative control serum was more than 4 times when 2 and 5 µg/ml of extracted proteins applied to the solid phase and 1:80,000 dilution of secondary antibody was used. The obtained results could be further developed into an ELISA assay or other immunological testing procedures for use as in-house testing. The tests can be used for assessing the situation of PCV2 infection disease in the farms, which are important tools to enhance the effectiveness of prevention and control of the disease at the herd level.