Attenuated SIV vaccine provides early protection against viral infection.

2004 MAY 5 - (NewsRx.com & NewsRx.net) -- Vaccination with attenuated simian immunodeficiency virus provided early protection against pathogenic viral infection at a mucosal challenge site.

"Atraumatic application of attenuated SIVmac239Deltanef vaccine to the tonsils of rhesus macaques provided protection against challenge 26 weeks later with infectious SIVmac251 applied through this route. Early events at the mucosal portal of entry of challenge virus were followed. Wild-type virus was detected in nonvaccinated controls by day 4, and then simian immunodeficiency virus (SIV) replicated vigorously at days 7 and 14," scientists in Germany, Austria, the United States, and the Netherlands report.

"In contrast, a challenge of 10 of 10 vaccinees with SIV did not significantly raise RNA levels in the plasma or increase infected cells in lymphoid tissues, as assessed by single-cell labeling for viral RNA and nef protein," stated Klara Tenner-Racz at the Bernhard Nocht Institute for Tropical Medicine in Hamburg and collaborators in Germany, Austria, the U.S., and the Netherlands. "Vaccine virus was found in the tonsils of all vaccinees, but challenge virus was only detected at this portal of entry in 4 of 10 monkeys. In the tonsil, the challenge virus did not induce an expansion of perforin+ killer cells. However, there was a significant increase in gammadelta T cells and ...