TABLE 4.

Protection of monkeys against DENV-4 challenge by passive transfer of IgG5H2 ΔDa

MonkeyAntibody (2 mg/kg) transferredViremia (day after challenge)SeroconversionProtection
Focus assay (FFU/ml)RT-PCR (FFU/ml equivalents)
H671No13 (6), 120 (7), 27 (8)120 (6), 500 (7), 550 (8)YesNo
H687NoNDNDYesNo
CF7HYesNDNDNoYes
CF7BYesNDNDNoYes
CJ4XYesNDNDNoYes
H742YesNDNDNoYes
  • a Two control monkeys (H671 and H687) received PBS in lieu of antibody. Rhesus monkeys were each challenged with 100 MID50 of DENV-4 1 day after antibody transfer. Viremia titer was analyzed by direct plaque analysis and by RT-PCR (TaqMan). Seroconversion was determined by the presence of anti-NS1 antibodies, as measured by radioimmunoprecipitation. Evidence of infection, i.e., seroconversion, was used to assess protection. ND, not detected.