Dengue 2 Virus Envelope Protein Expressed by a Recombinant Vaccinia Virus Fails to Protect Monkeys against Dengue

Abstract

SUMMARYA cDNA copy of the dengue (DEN) 2 virus genome region encoding the virion capsid, membrane and envelope structural proteins has been inserted into vaccinia virus (VV) DNA under the control of its 11K late promoter. The DEN-2 envelope protein was expressed and processed in cells infected with the VV recombinant (VV/D2S). No DEN-2 virus antibody response was detected in mice, hamsters or monkeys vaccinated with VV/D2S. Furthermore, a viraemia was observed in recombinant-vaccinated monkeys after challenge with infectious DEN-2 virus.

Expression of the structural proteins of dengue 2 virus and yellow fever virus by recombinant vaccinia viruses

“…In recombinant-infected tissue culture cells the inserted cDNAs are expressed and translated into DEN or YF prM and E proteins which are correctly cleaved and modified. Similar results have also been obtained for DEN 4 [3,40] and DEN 2 Jamaica strain [8] suggesting that cleavages to produce flavivirus structural proteins can occur in the absence of the nonstructural proteins. When it becomes possible to construct and study the effects of site-directed mutations on flavivirus structural protein function in the context of virus replication and assembly, such recombinants may allow packaging of mutants with lethal defects in these proteins.…”

“…Subsequent experiments using weanling mice showed that constructs expressing the DEN 4 structural proteins with or without NS 1 (see below) could protect against fatal DEN 4-induced encephalitis although neutralizing antibody titers were low or not detectable [3]. In studies with a vaccinia recombinant expressing the structural proteins of the Jamaica strain of DEN 2 under the control of the 11 kDa vaccinia late promoter (as opposed to the constitutive 7.5 kDa early/late promoter used in our studies), neither mice, hamsters nor monkeys produced detectable DEN 2 neutralizing antibodies [8]. Furthermore, viremia was still observed in monkeys challenged with DEN 2.…”

Protective efficacy in mice of a secreted form of recombinant dengue-2 virus envelope protein produced in baculovirus infected insect cells

“…The Autographacalifornicanuclearpolyhedrosisvirus (AcNPV) D2 EA 102 gene was recombined into the AcRp231acZ genome as described previously [4] Several strategies have been explored to produce this antigen in a form that conserves its protective efficacy as evaluated in animal models. DEN E-glycoproteins, produced either in vaccinia or in baculovirus vectors show variations in processing, antigenicity and immunogenic properties [3,4,5,6,11,19,20,26,27]. It is unclear whether the low immunogenicity of some of these E-protein constructs is related to the virus vector, to the DEN serotype or to the nature of the construct.…”

“…Baculovirus-expressed DEN-1 EA82 protein was intraceltular and was not secreted into the extracellular m e d i u m [20]. The discrepancy in retention between D E N E-proteins is not well [6] or infected with 105 PFU of live DEN-2 Jam virus were used for positive controls. Immunized mice were bled two weeks after the last injection b The yield of recombinant proteins in cell lysate or in extracellular medium was estimated by comparison with bovine albumin standard in Coomassie-stained SDS-PAGE c Pooled sera were obtained by combining equal aliquots from three mice in each experimental group d Sera were analyzed as 1/100 dilutions.…”

Yucatan Miniature Swine as an Animal Model for Dengue-1 Disease

“…There are three non-human primate models that are currently used in dengue studies: Aotus nancymae, Rhesus macaque, and Cynomologous macaque 47,48,49 . Non-human primates develop an asymptomatic dengue virus infection, but have 2 to 5 days of detectable viremia as determined by cell culture isolation 47 .…”