Site-specific characterization of envelope protein N-glycosylation on Sanofi Pasteur's tetravalent CYD dengue vaccine.

Recently, several virus studies have shown that protein glycosylation play a fundamental role in the virus-host cell interaction. Glycosylation characterization of the envelope proteins in both insect and mammalian cell-derived dengue virus (DENV) has established that two potential glycosylation residues, the asparagine 67 and 153 can potentially be glycosylated. Moreover, it appears that the glycosylation of these two residues can influence dramatically the virus production and the infection spreading in either mosquito or mammalian cells. The Sanofi Pasteur tetravalent dengue vaccine (CYD) consists of four chimeric viruses produced in mammalian vero cells. As DENV, the CYDs are able to infect human monocyte-derived dendritic cells in vitro via C-type lectins cell-surface molecules. Despite the importance of this interaction, the specific glycosylation pattern of the DENV has not been clearly documented so far. In this paper, we investigated the structure of the N-linked glycans in the four CYD serotypes. Using MALDI-TOF analysis, the N-linked glycans of CYDs were found to be a mix of high-mannose, hybrid and complex glycans. Site-specific N-glycosylation analysis of CYDs using nanoLC-ESI-MS/MS demonstrates that both asparagine residues 67 and 153 are glycosylated. Predominant glycoforms at asparagine 67 are high mannose-type structures while mainly complex- and hybrid-type structures are detected at asparagine 153. In vitro studies have shown that the immunological consequences of infection by the CYD dengue viruses 1-4 versus the wild type parents are comparable in human monocyte-derived dendritic cells. Our E-protein glycan characterizations of CYD are consistent with those observations from the wild type parents and thus support in vitro studies. In addition, these data provide new insights for the role of glycans in the dengue virus-host cell interactions.

Evaluation of interferences between dengue vaccine serotypes in a monkey model.

Interferences between different antigens in the same vaccine formulation have been reported for some vaccines (e.g., polio vaccines, live attenuated dengue vaccine candidates). We examined interferences between the four serotypes of ChimeriVax dengue vaccines (CYDs) in a monkey model when present within a tetravalent formulation in equal concentrations (TV-5555). Immunoassays of vaccinated non-human primates showed that serotype 4 (DEN-4), and to a lesser extent, DEN-1 were dominant in terms of neutralizing antibody levels. Parameters that affected the interferences were identified, including 1) the simultaneous administration of two complementary bivalent vaccines at separate anatomical sites drained by different lymph nodes; 2) the sequential administration of two complementary bivalent vaccines; 3) the establishment of heterologous flavivirus pre-immunity before subsequent tetravalent immunization; 4) the adaptation of formulations by decreasing the dose of the immunodominant serotype; and 5) the administration of a 1-year booster. The applicability of these data to human responses is discussed.