Universal Dengue Vaccine Elicits Neutralizing Antibodies against Strains from All Four Dengue Virus Serotypes

Abstract

Any potential dengue virus (DENV) vaccine needs to elicit protective immunity against strains from all four serotypes to avoid potential antibody dependent enhancement (ADE). In this study, four independent DENV envelope (E) glycoproteins were generated using wild-type E sequences from viruses isolated between 1943 to 2006 using computationally-optimized broadly reactive antigen (COBRA) methodology. COBRA and wild-type E antigens were expressed on the surface of subvirion viral particles (SVPs). Four separate wild-type E antigens were used for each serotype. Mice vaccinated with wild-type DENV SVPs had anti-E IgG antibodies that neutralized serotype specific viruses. COBRA DENV SVPs elicited a broader breadth of antibodies that neutralized strains across all four serotypes. Two COBRA DENV vaccine candidates that elicited the broadest breadth of neutralizing antibodies in mice were used to vaccinate rhesus macaques (Macca mulata) that were either immunologically naïve to any DENV serotype or were had pre-existing antibodies to DENV. Antibodies elicited by COBRA DENV E immunogens neutralized all 12 strains of DENV in vitro, which was comparable to antibodies elicited by a tetravalent wild-type E SVP vaccination mixture. Therefore, using a single DENV COBRA E protein can elicit neutralizing antibodies against strains representing all four serotypes of DENV in both naïve and dengue pre-immune populations. Importance Dengue virus infects millions of people living in the tropical areas of the world. Dengue induced diseases can range from mild to severe with death. An effective vaccine will need to neutralize viruses from all four serotypes of dengue without induced enhanced disease. A dengue E vaccine candidate generated by computationally optimized broadly reactive antigen algorithms elicits broadly neutralizing protection for current circulating strains from all four serotypes regardless of immune status. Most Dengue vaccines in development formulate four separate components based on prM-E from a wild type strain representing each serotype. Designing a monovalent vaccine that elicits protective immunity against all four serotypes is an effective and economical strategy

Inherent Serum Inhibition of Influenza Virus Neuraminidases

“…Sera were confirmed to be negative for preexisting antibodies to currently circulating human influenza viruses by HAI. Ferret sera originated from 6 to 8-months female finch ferrets ( Mustela putorius furo , spayed, female, 6–8 months, descented) purchased from Triple F Farms (Sayre, PA); porcine sera originated from piglets at Auburn University; and rhesus macaque ( Macaca mulatta ) sera originated from previous dengue virus studies performed in the lab ( 27 ). The rat (cat #: 10710C), goat (cat #: 01-6201), horse (cat #: 31874), and mouse (cat #: 01-6501; NIH Swiss mouse) normal sera were harvested from non-immune animals (Invitrogen, Carlsbad, CA, USA) and rehydrated according to the manufacturer's specification; only one lot was tested for each commercial serum.…”

Protein engineering strategies for rational immunogen design

“…The COBRA approach translates to other human (e.g., H1, H2, H3), avian (e.g., H7), and swine (e.g., H1) HAs, as well as other viral antigens such as dengue virus E protein. Importantly these immunogens work in both naïve animal models and in the setting of preexisting immunity [135][136][137][138][139][140][141][142][143][144][145][146][147] . The exact mechanism of enhanced breadth elicited by COBRA immunogens is unknown; one possibility is increased recruitment of B cells against antigenic sites with greater cross-reactive potential leads to the enhanced diversity and breadth of responses 148,149 .…”