Hepatitis delta antigens cause varied immunity in mice.

2004 FEB 11 - (NewsRx.com & NewsRx.net) -- DNA vaccines consisting of large and small hepatitis delta antigens cause varied immunity in mice.

"Whether the hepatitis delta virus (HDV) DNA vaccine can induce anti-HDV antibodies has been debatable. The role of the isoprenylated motif of hepatitis delta antigens (HDAg) in the generation of immune responses following DNA-based immunization has never been studied. Plasmids p2577L, encoding large HDAg (L-HDAg), p2577S, expressing small HDAg (S-HDAg), and p25L-211S, encoding a mutant form of L-HDAg with a cysteine-to-serine mutation at codon 211, were constructed in this study," scientists in Taiwan report.

"Mice were intramuscularly injected with the plasmids," said Yi-Hsiang Huang and collaborators at National Yang-Ming University and Taipei Veterans General Hospital. "The anti-HDV antibody titers, T-cell proliferation responses, T-helper responses, and HDV-specific, gamma interferon (IFN-gamma)-producing CD8+ T cells were analyzed. Animals immunized with p2577S showed a strong anti-HDV antibody response. Conversely, only a low titer of anti-HDV antibodies was detected in mice immunized with p2577L."

"Epitope mapping revealed that the anti-HDV antibodies generated by p2577L vaccination hardly reacted with epitope amino acids 174 to 194, located at the C terminus of S-HDAg," reported the researchers. "All of the HDAg-encoding plasmids could induce significant T-cell proliferation responses and ...