Immunization with a plasmid DNA expressing rinderpest virus hemagglutinin protein protects rabbits from lethal challenge - Brief report

Rinderpest virus haemagglutinin (H) protein was expressed in eukaryotic cells and the plasmid encoding H gene was used for immunization of rabbits. The immunized rabbits were completely protected from lethal challenge with virulent lapinized rinderpest virus. Similar results were also observed in rabbits vaccinated with tissue culture rinderpest (TCRP) vaccine. About 80% of control rabbits vaccinated with empty vector (mock-vaccinated) died after challenge. The thermal reactions and clinical symptoms were less intense in H-DNA vaccinated rabbits as compared to the other two groups. Marked lymphopenia was observed in TCRP and mock-vaccinated rabbits after challenge, however, the H-DNA vaccinated rabbits showed lymphocytosis following challenge. The appearance of lymphocytosis in H-DNA vaccinated rabbits is an interesting finding which needs further investigation.