Lack of viraemia and limited antibody response of dengue virus immune rhesus monkeys after vaccination with DEN-2/S-1 vaccine

Abstract

A dengue-2 live virus vaccine was tested in monkeys immune to heterologous dengue serotypes to determine if, as with wild DEN-2 virus, antibody-enhanced viraemia and seroconversion would occur. A low dose of 900 plaque-forming units (PFU) of the DEN-2/S-1 vaccine virus was inoculated subcutaneously into rhesus monkeys six months after they had received wild DEN-1, DEN-2 or DEN-3 viruses, and into non-immune monkeys. As previously reported for non-immune monkeys, there was little, if any, detectable vaccine viraemia in any of the groups of monkeys. There was no difference in seroconversion between the dengue heterologously immune (3/6) and non-immune (1/3) monkeys. These data indicated that (i) the vaccine virus may differ from the parent virus in the ability to complex with heterologous antibody and, thus, in the ability to infect Fc receptor bearing cells in monkeys; (ii) 10(3) PFU of vaccine virus is approximately the 50% infectious dose in monkeys as measured by seroconversion.

Endothelial cells in dengue hemorrhagic fever

“…DENV infected rhesus monkeys demonstrated productive viremia (Freire et al, 2007; Kraiselburd et al, 1985; Scott et al, 1980) and have been used for pre-clinical vaccination(Blaney et al, 2008; Bray et al, 1996; Guirakhoo et al, 2001; Kraiselburd et al, 1984; Martin et al, 2009; Putnak et al, 2003; Raviprakash et al, 2008; Simmons et al, 2010; Sun et al, 2006) and antiviral studies(Ajariyakhajorn et al, 2005; Malinoski et al, 1990). Studies using these models did not assess if endothelial cells expressed virus antigen after DENV infection in these animal models.…”