The seroepidemiology of dengue in a US military population based in Puerto Rico during the early phase of the Zika pandemic.

Understanding the burden and risk factors of dengue virus (DENV) infection in Puerto Rico is important for the prevention of dengue in local, traveler and military populations. Using sera from the Department of Defense Serum Repository, we estimated the prevalence and predictors of DENV seropositivity in those who had served in Puerto Rico, stratified by birth or prior residence ("birth/residence") in dengue-endemic versus non-endemic regions. We selected sera collected in early 2015 from 500 U.

Enhanced dengue vaccine virus replication and neutralizing antibody responses in immune primed rhesus macaques.

Antibody-dependent enhancement (ADE) is suspected to influence dengue virus (DENV) infection, but the role ADE plays in vaccination strategies incorporating live attenuated virus components is less clear. Using a heterologous prime-boost strategy in rhesus macaques, we examine the effect of priming with DENV purified inactivated vaccines (PIVs) on a tetravalent live attenuated vaccine (LAV). Sera exhibited low-level neutralizing antibodies (NAb) post PIV priming, yet moderate to high in vitro ADE activity.

Delineating the serotype-specific neutralizing antibody response to a live attenuated tetravalent dengue vaccine.

The dengue virus (DENV) vaccines that are licensed or in clinical development consist of DENV serotype 1-4 tetravalent formulations given simultaneously and are not acquired sequentially like natural infections. It is unclear what effect this has on development of protective levels of immunity to all four serotypes. Serotype-specific neutralizing antibody (NAb) is considered the most relevant correlate of protection from dengue disease.

Phenotypic analysis of dengue virus isolates associated with dengue fever and dengue hemorrhagic fever for cellular attachment, replication and interferon signaling ability.

Eighteen dengue viruses (DENVs) representing all four serotypes, isolated from pediatric patients at children's hospital, Queen Sirikit National Institute of Child Health, Bangkok, Thailand exhibiting a diverse spectrum of disease ranging from uncomplicated dengue fever (DF) to severe dengue hemorrhagic fever (DHF), were tested for their ability to attach to host cells, replicate and interfere with the IFNalpha signaling pathway by interfering with signal transducer and activator of transcription 1 (STAT-1) function. Although most isolates suppressed IFNalpha-induced STAT-1 phosphorylation, our results showed no difference between DENV strains associated with DF and those associated with DHF. However, the DHF isolates tended replicate to higher titers in dendritic cells (DCs) than the DF isolates, but this ability was independent of their cell-binding capability.

Restricted replication and lysosomal trafficking of yellow fever 17D vaccine virus in human dendritic cells.

The yellow fever virus attenuated 17D vaccine strain is a safe and effective vaccine and a valuable model system for evaluating immune responses against attenuated viral variants. This study compared the in vitro interactions of the commercially available yellow fever vaccine (YF-VAX), Dengue virus and the live-attenuated dengue vaccine PDK50 with dendritic cells (DCs), the main antigen-presenting cells at the initiation of immune responses. Similar to PDK50, infection with YF-VAX generated activated DCs; however, for YF-VAX, activation occurred with limited intracellular virus replication.