Recombinant Dengue Virus 4 Envelope Glycoprotein Virus-Like Particles Derived from
            Pichia pastoris
            are Capable of Eliciting Homotypic Domain III-Directed Neutralizing Antibodies

The flavivirus envelope protein domain III (EDIII) was an effective immunogen against dengue virus (DENV) and other related flaviviruses. Whether this can be applied to the Zika virus (ZIKV) vaccinology remains an open question. Here, we tested the efficacy of ZIKV-EDIII against ZIKV infection, using several vaccine platforms that present the antigen in various ways. We provide data demonstrating that mice vaccinated with a ZIKV-EDIII as DNA or protein-based vaccines failed to raise fully neutralizing antibodies and did not control viremia, following a ZIKV challenge, despite eliciting robust antibody responses. Furthermore, we showed that ZIKV-EDIII encoded in replication-deficient Chimpanzee adenovirus (ChAdOx1-EDIII) elicited anti-ZIKV envelope antibodies in vaccinated mice but also provided limited protection against ZIKV in two physiologically different mouse challenge models. Taken together, our data indicate that contrary to what was shown for other flaviviruses like the dengue virus, which has close similarities with ZIKV-EDIII, this antigen might not be a suitable vaccine candidate for the correct induction of protective immune responses against ZIKV.

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Comparison of Plaque- and Enzyme-Linked Immunospot-Based Assays To Measure the Neutralizing Activities of Monoclonal Antibodies Specific to Domain III of Dengue Virus Envelope Protein

Clinical and Vaccine Immunology ◽

10.1128/cvi.05388-11 ◽

2011 ◽

Vol 19 (1) ◽

pp. 73-78 ◽

Cited By ~ 28

Author(s):

Lidong Liu ◽

Kun Wen ◽

Jie Li ◽

Dongmei Hu ◽

Yanfen Huang ◽

...

Keyword(s):

Monoclonal Antibodies ◽

Dengue Virus ◽

Envelope Protein ◽

Neutralizing Antibodies ◽

Large Scale ◽

Immunofluorescence Assay ◽

Virus Envelope ◽

Virus Envelope Protein ◽

Domain Iii ◽

Microneutralization Test

ABSTRACTThe plaque reduction neutralization test (PRNT) is used widely to measure the neutralization activity of anti-dengue virus (DENV) antibodies, but it is time-consuming and labor-intensive and has low sample throughput. For fast and convenient measurement of neutralizing antibodies, especially in evaluating the efficiency of the DENV vaccines on a large scale, a new method is needed to replace PRNT. In recent decades, several microneutralization assays have been developed to overcome the limitations of PRNT. In the present study, we evaluated one of these, the enzyme-linked immunospot microneutralization test (ELISPOT-MNT), in comparison with PRNT. ELISPOT-MNT is performed in 96-well format, and the plaques are developed after 2 to 4 days using an ELISA to transform them into spots, which are detected automatically with an ELISPOT instrument. The assay is faster than PRNT, has a high throughput, and is more objective. We used 10 monoclonal antibodies (MAbs) against domain III of the DENV envelope protein (EDIII) to evaluate the two assays; all of these MAbs cross-react with all four serotypes of DENV as measured by immunofluorescence assay. The two neutralization assays were performed simultaneously to measure the 50% inhibitory concentration (IC50) of these MAbs. Using PRNT as the reference and treating IC50values higher than 50 μg/ml of MAbs as negative, ELISPOT-MNT showed a sensitivity of 95.6% and specificity of 88.24% when 10 MAbs were tested against four DENV serotype strains. A good correlation (R2= 0.672;P= 0.000) was observed between the two assays, making ELISPOT-MNT a potentially valuable method for measure of neutralizing antibodies against DENV.

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