MAB8703 Sigma-AldrichAnti-Dengue Virus Type III Antibody, clone 5D4-11

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.

Monoclonal antibodies directed against antigenic determinants of the New Guinea C strain of dengue-2 virus were obtained from lymphocyte hybridomas produced by fusing immune mouse lymphocytes with mouse myeloma cells. Hybridoma cell culture supernatants were screened by using a radioimmunoassay employing detergent-solubilized dengue-2 infected cell antigens. Monoclonal antibodies in ascitic fluids induced by 22 selected hybridomas were characterized by the hemagglutination-inhibition, plaque reduction neutralization, immunofluorescence, and complement-fixation tests. Both type-specific and broadly cross-reactive antibodies were observed, and immunoglobulin subclasses IgG1 and IgG2a were represented in both groups. At least three distinct antigenic determinants on the virion were defined using these antibodies. A single hybridoma produced antibody which recognized a dengue-2 virus type-specific determinant and exhibited high titered neutralization but had a low titer by hemagglutination inhibition. Four preparations reacted with a type-specific determinant and exhibited hemagglutination inhibition but did not neutralize. Seventeen hybridomas produced antibodies which were broadly cross reactive in all tests. Only two preparations reacted by complement fixation with dengue-2 antigens; both were cross reactive. Immunofluorescence specificity or cross reactivity correlated with neutralization and/or hemagglutination-inhibition. The dengue-2 virus type-specific antibody useful for identification of dengue-2 infected cells by immunofluorescence has been deposited in the Hybridoma Cell Bank of the American Type Culture Collection.