An epidemic Zika virus isolate suppresses antiviral immunity by disrupting antigen presentation pathways

Current Advances in Zika Vaccine Development

Zika virus (ZIKV), an emerging arthropod-borne flavivirus, was first isolated in Uganda in 1947 from monkeys and first detected in humans in Nigeria in 1952; it has been associated with a dramatic burden worldwide. Since then, interventions to reduce the burden of ZIKV infection have been mainly restricted to mosquito control, which in the end proved to be insufficient by itself. Hence, the situation prompted scientists to increase research on antivirals and vaccines against the virus. These efforts are still ongoing as the pathogenesis and immune evasion mechanisms of ZIKV have not yet been fully elucidated. Understanding the viral disease mechanism will provide a better landscape to develop prophylactic and therapeutic strategies against ZIKV. Currently, no specific vaccines or drugs have been approved for ZIKV. However, some are undergoing clinical trials. Notably, different platforms have been evaluated for the design of vaccines, including DNA, mRNA, viral vectors, virus-like particles (VLPs), inactivated virus, live attenuated virus, peptide and protein-based vaccines, passive immunizations by using monoclonal antibodies (MAbs), and vaccines that target vector-derived antigens. These vaccines have been shown to induce specific humoral and cellular immune responses and reduce viremia and viral RNA titers, both in vitro and in vivo. This review provides a comprehensive summary of current advancements in the development of vaccines against Zika virus.

An Epidemic Zika Virus Isolate Drives Enhanced T Follicular Helper Cell and B Cell-Mediated Immunity

Zika virus (ZIKV) is a mosquito-borne pathogen that recently caused a series of increasingly severe outbreaks. We previously demonstrated that, compared with a pre-epidemic isolate (ZIKVCDN), a Brazilian ZIKV isolate (ZIKVBR) possesses a novel capacity to suppress host immunity, resulting in delayed viral clearance. However, whether ZIKVBR modulates CD4 T cell responses remains unknown. In this study, we show that, in comparison with ZIKVCDN infection, CD4 T cells are less polarized to the Th1 subtype following ZIKVBR challenge in mice. In contrast, we observed an enhanced accumulation of T follicular helper cells 10, 14, and 21 d postinfection with ZIKVBR This response correlated with an enhanced germinal center B cell response and robust production of higher avidity-neutralizing Abs following ZIKVBR infection. Taken together, our data suggest that contemporary ZIKV strains have evolved to differentially induce CD4 T cell, B cell, and Ab responses and this could provide a model to further define the signals required for T follicular helper cell development.