Construction, Safety, and Immunogenicity in Nonhuman Primates of a Chimeric Yellow Fever-Dengue Virus Tetravalent Vaccine

Abstract

We previously reported construction of a chimeric yellow fever-dengue type 2 virus (YF/DEN2) and determined its safety and protective efficacy in rhesus monkeys (F. Guirakhoo et al., J. Virol. 74:5477-5485, 2000). In this paper, we describe construction of three additional YF/DEN chimeras using premembrane (prM) and envelope (E) genes of wild-type (WT) clinical isolates: DEN1 (strain PUO359, isolated in 1980 in Thailand), DEN3 (strain PaH881/88, isolated in 1988 in Thailand), and DEN4 (strain 1228, isolated in 1978 in Indonesia). These chimeric viruses (YF/DEN1, YF/DEN3, and YF/DEN4) replicated to ϳ7.5 log 10 PFU/ml in Vero cells, were not neurovirulent in 3-to 4-week-old ICR mice inoculated by the intracerebral route, and were immunogenic in monkeys. All rhesus monkeys inoculated subcutaneously with one dose of these chimeric viruses (as monovalent or tetravalent formulation) developed viremia with magnitudes similar to that of the YF 17D vaccine strain (YF-VAX) but significantly lower than those of their parent WT viruses. Eight of nine monkeys inoculated with monovalent YF/DEN1 -3, or -4 vaccine and six of six monkeys inoculated with tetravalent YF/DEN1-4 vaccine seroconverted after a single dose. When monkeys were boosted with a tetravalent YF/ DEN1-4 dose 6 months later, four of nine monkeys in the monovalent YF/DEN groups developed low levels of viremia, whereas no viremia was detected in any animals previously inoculated with either YF/DEN1-4 vaccine or WT DEN virus. An anamnestic response was observed in all monkeys after the second dose. No statistically significant difference in levels of neutralizing antibodies was observed between YF virus-immune and nonimmune monkeys which received the tetravalent YF/DEN1-4 vaccine or between tetravalent YF/DEN1-4-immune and nonimmune monkeys which received the YF-VAX. However, preimmune monkeys developed either no detectable viremia or a level of viremia lower than that in nonimmune controls. This is the first recombinant tetravalent dengue vaccine successfully evaluated in nonhuman primates.

Live Attenuated Chimeric Yellow Fever Dengue Type 2 (ChimeriVax™-DEN2) Vaccine: Phase I Clinical Trial for Safety and Immunogenicity: Effect of Yellow Fever Pre-immunity in Induction of Cross Neutralizing Antibody Responses to All

“…27 However, the opposite was not true, since prevaccination with DEN2 vaccine did not increase the seroconversion rate against YF vaccine. 8,33,34 The T-cell responses in this clinical trial were consistent with the neutralizing antibody responses in that both doses of vaccine stimulated similar T cell immune responses, and prior immunity to YF Phase 1 Study of Live Attenuated ChimeriVax TM -DEN2 Vaccine virus did not inhibit the T cell response to ChimeriVax™-DEN2. IFNγ responses were virtually the same for the 2 doses of ChimeriVax™-DEN2 (10 3 and 10 5 pfu).…”

“…7 ChimeriVax™-DEN2 is a live, attenuated, genetically engineered virus prepared by replacing the genes encoding the two structural proteins, premembrane (prM) and envelope (E), of the YF 17D vaccine virus with the corresponding genes of the DEN2 virus (strain PUO-218, isolated from a case of classical DF, Bangkok, Thailand). 8 It is a monovalent component of a tetravalent vaccine formulation 9 currently being investigated in a Phase 2 study. Preclinical studies have demonstrated that the ChimeriVax™-DEN2 virus was is not neurovirulent when administered to adult mice via the intracerebral (IC) route, is genetically stable in cell culture, induces low levels of viremia, and protects 100% of monkeys against wt DEN2 heterologous challenge upon a single SC immunization.…”

Histidine 39 in the dengue virus type 2 M protein has an important role in virus assembly

“…Transient expression of pSVprM H39R -E resulted in the formation of intracellular prM/E heterodimers and secretion of the prM and E proteins in a particulate form at similar levels to those of the parental construct. A HisRArg substitution at M39, in addition to two changes in the E protein, was identified in a chimeric DENV-1/YFV, which caused decreased viraemia in monkeys compared with the parental DENV-1 and YFV (Guirakhoo et al, 2001). The contribution of the M39 Arg mutation to the monkey attenuation phenotype has not been reported.…”

The yellow fever 17D virus as a platform for new live attenuated vaccines

“…36 Although the prM-E genes may vary among diverse flaviviruses by over 40% of the encoded amino acids, chimeric 17D viruses are still viable. The gene fusion is made at the signal peptidase cleavage site between C and prM and the signal peptidase site at the E and NS1 junction.…”