Dengue Reporter Virus Particles for Measuring Neutralizing Antibodies against Each of the Four Dengue Serotypes
Figure 2
DENV RVPs are infectious under conditions commonly used in neutralization assays and following long-term cryopreservation.
DENV RVPs representing all 4 serotypes were incubated at 4°C (A), 25°C (B), or at 37°C (C) for up to 10 hours, followed by infection of Raji DC-SIGN-R cells. Forty-eight hours post-infection, cells were analyzed for GFP expression by flow cytometry. At all temperatures, DENV RVPs remain highly infectious after a 2-hour incubation (a typical incubation period used in neutralization assays, vertical dashed line). (D) A single preparation of DENV-2 RVPs was aliquoted and frozen at −80°C from 2 days up to 1 year prior to infection of Raji DC-SIGN-R cells. Forty-eight hours after infection, cells were analyzed for GFP expression by flow cytometry. DENV RVPs showed little or no substantial loss of infectivity after long-term cryopreservation (n = 2, error bars represent the range).