TABLE 2.

Comparison of neutralizing antibody titers using prototype DENV, ChimeriVax-DENV, and ChimeriVax-DENV parental strains in PRNT90

Specimen type (no. of samples)Specimen no.Neutralizing antibody titers in PRNT90a
Prototype DENVChimeriVax-DENVChimeriVax-DENV parental strains
DENV1DENV2DENV3DENV4DENV1DENV2DENV3DENV4DENV1DENV2DENV3DENV4
DENV1 infection (15)11,2805,12040160
21,28040640402016020
36408020160
416032020
5160160160
61608080
73202,560404020320
81,280402032080802064040
9404040
10320640160
1132020640202032020
126404020201,280804064020
1380NDNDND160NDNDND160NDNDND
144064020160
1520802040
DENV2 infection (12)1620320640160
174016032080
184064064020320
19160640204064040402032020
204032032080
218016080
22160320320
2320320203202016020
24203201,28020160
2516064040
263201,280320
276401,280320
DENV3 infection (3)28
29404080
302016020320160
DENV4 infection (3)311,280160320
322032020160320
33405,120202,5605,120
Secondary DENV infection (3)341,2806406406406401,2803206401,28032064080
355,1202,5605,1205,1205,12010,2402,5605,1205,1201,28010,2401,280
3610,2405,12010,24040,9605,12020,4805,12040,96010,2402,56020,48010,240
WNV infection (3)37-39
YFV vaccinated (3)40-42
All flavivirus negative (6)43-48
Positive controlsb
    DENV1640 (5,120)(80)(160)(80)2,560 (2,560)(80)(320)(160)1,280 (320)(20)(40)(—)
    DENV2(320)1,280 (1,280)(80)(160)(160)2,560 (2,560)(160)(80)(—)640 (80)(—)(—)
    DENV3(320)(160)1,280 (1,280)(160)(320)(160)640 (2,560)(80)(80)(40)1,280 (320)(—)
    DENV4(160)(80)(80)5,120 (5,120)(160)(80)(80)2,560 (2,560)(—)(—)(—)1,280 (80)
Negative controlc
  • a The neutralizing antibody titer is expressed as the reciprocal of the endpoint serum dilution that neutralized the challenge virus plaque count by 90%. LLOQ has a neutralizing antibody titer of 20; only positive titers (≥20) are shown. Dash = no detectable titer (<20). A neutralizing titer difference of more than fourfold between antibody to the homologous DENV serotype and antibodies to the other DENV serotypes indicates a DENV serotype-specific antibody response. The neutralizing antibody titers in parentheses are the results of the initial evaluations of the MHIAF samples using each of the four DENV serotypes as challenge viruses. These titers are shown to illustrate the level of cross-reactivity of the MHIAF samples to the other DENV serotypes. ND, not done due to insufficient sample volume.

  • b MHIAF produced against a single DENV serotype.

  • c Normal human control serum.