Evaluation by flow cytometry of antibody-dependent enhancement (ADE) of dengue infection by sera from Thai children immunized with a live-attenuated tetravalent dengue vaccine.
Sera from Thai children immunized with a live-attenuated tetravalent dengue virus vaccine or from naturally infected age-matched site-control subjects were examined for immune enhancement capacity by a highly reproducible flow cytometric assay in Fc receptor-bearing K562 human cells. None of the sera under study corresponded to cases of severe dengue disease. In parallel assays employing each dengue virus serotype, we found no or only minimal antibody-dependent enhancement (ADE) when sera from vaccinated or control subjects were used at a low serum dilution [1/12] that approximated the in vivo condition. Among sera that exhibited homotypic neutralizing antibody activity against DV1-3, the level correlated with absence of ADE or infection with the respective serotype. Similarly, a broad heterotypic neutralizing antibody response that included all four serotypes was linked to complete absence of K562 cell infection. In contrast, at higher serum dilutions a correlation between breadth of antibody response and heightened immune enhancement emerged, a pattern identical to that observed among control subjects. These findings support the use of live dengue vaccines and protocols that induce broad serotype-specific neutralizing antibody responses, but they also suggest that clinically relevant immune enhancement may not be likely if this is not uniformly achieved after the first immunization.
Guy
Bruno
B
R&D Department, Aventis Pasteur, Lyon, France. bruno.guy@aventis.com
Chanthavanich
Pornthep
P
Gimenez
Sophie
S
Sirivichayakul
Chukiat
C
Sabchareon
Arunee
A
Begue
Sarah
S
Yoksan
Sutee
S
Luxemburger
Christine
C
Lang
Jean
J
D000293:Adolescent; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral / Q000276:immunology*; D019067:Antibody-Dependent Enhancement / Q000276:immunology*; D002463:Cell Membrane Permeability; D002648:Child; D002675:Child, Preschool; D003715:Dengue / Q000276:immunology*; D003716:Dengue Virus / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D020014:K562 Cells; D008297:Male; D009500:Neutralization Tests; D011961:Receptors, Fc / Q000276:immunology; D013785:Thailand; D016707:Tissue Fixation; D014613:Vaccines, Attenuated / Q000627:therapeutic use; D010948:Viral Plaque Assay; D014765:Viral Vaccines / Q000009:adverse effects*; D014779:Virus Replication
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D011961:Receptors, Fc; D014613:Vaccines, Attenuated; D014765:Viral Vaccines