Development of a recombinant tetravalent dengue virus vaccine: Immunogenicity and efficacy studies in mice and monkeys

Abstract

Truncated recombinant dengue virus envelope protein subunits (80E) are efficiently expressed using the Drosophila Schneider-2 (S2) cell expression system. Binding of conformationally sensitive antibodies as well as x-ray crystal structural studies indicate that the recombinant 80E subunits are properly folded native-like proteins. Combining the 80E subunits from each of the four dengue serotypes with ISCOMATRIX® adjuvant, an adjuvant selected from a set of adjuvants tested for maximal and long lasting immune responses, results in high titer virus neutralizing antibody responses. Immunization of mice with a mixture of all four 80E subunits and ISCOMATRIX® adjuvant resulted in potent virus neutralizing antibody responses to each of the four serotypes. The responses to the components of the tetravalent mixture were equivalent to the responses to each of the subunits administered individually. In an effort to evaluate the potential protective efficacy of the Drosophila expressed 80E, the dengue serotype 2 (DEN2-80E) subunit was tested in both the mouse and monkey challenge models. In both models protection against viral challenge was achieved with low doses of antigen in the vaccine formulation. In non-human primates, low doses of the tetravalent formulation induced good virus neutralizing antibody titers to all four serotypes and protection against challenge with the two dengue virus serotypes tested. In contrast to previous reports, where subunit vaccine candidates have generally failed to induce potent, protective responses, native-like soluble 80E proteins expressed in the Drosophila S2 cells and administered with appropriate adjuvants are highly immunogenic and capable of eliciting protective responses in both mice and monkeys. These results support the development of a dengue virus tetravalent vaccine based on the four 80E subunits produced in the Drosophila S2 cell expression system.

DENV-2 subunit proteins fused to CR2 receptor-binding domain (P28)-induces specific and neutralizing antibodies to the Dengue virus in mice

“…36,37 Indeed, utilization of E protein truncated at amino acid 395 expressed in the Drosophila S2 system has provided important advances toward the generation of a safe and effective tetravalent dengue subunit vaccine. 19,21 To reduce the risk of cross-reactive antibodies, some studies have focused on domain III of the E protein. 19,20 However, during the course of natural infection, antibodies against domain II are elicited, and these antibodies induce the production of cross reactive antibodies with a low neutralizing activity.…”

“…19,21 To reduce the risk of cross-reactive antibodies, some studies have focused on domain III of the E protein. 19,20 However, during the course of natural infection, antibodies against domain II are elicited, and these antibodies induce the production of cross reactive antibodies with a low neutralizing activity. [8][9][10]38 Therefore, vaccines composed of the relevant sequence of domain II and the whole domain III may trigger a more effective immune response.…”

“…18 Domain III of DENV-2 expressed in this system was able to elicit a protective response in mice and monkeys. [19][20][21] Due to the low immunogenicity that the recombinant proteins in general possess, different strategies have been implemented to elicit a robust immune response against these antigens. Domain III (DIII) of the dengue virus (DeNV) envelope (e) protein induces strong neutralizing type-specific antibodies.…”

Development of DENVax: A chimeric dengue-2 PDK-53-based tetravalent vaccine for protection against dengue fever

“…A recombinant protein vaccine consisting of adjuvanted recombinant envelope (E) proteins expressed in insect cells [22] has completed monovalent Phase 1 clinical testing and tetravalent formulations have been manufactured (reviewed by Coller et al, this issue). Several additional approaches are currently being evaluated in preclinical studies.…”

“…Several additional approaches are currently being evaluated in preclinical studies. They include the use of (1) adenoviral vectors that express combinations of two of the four dengue serotypes [23,24]; (2) DNA vaccines expressing the E protein [25]; and (3) the E protein domain III either alone [26], or as domain-based single recombinant envelope protein that can induce tetravalent neutralizing antibody responses [27].…”