Heterologous Protection against Asian Zika Virus Challenge in Rhesus Macaques

Abstract

BackgroundZika virus (ZIKV; Flaviviridae, Flavivirus) was declared a public health emergency of international concern by the World Health Organization (WHO) in February 2016, because of the evidence linking infection with ZIKV to neurological complications, such as Guillain-Barre Syndrome in adults and congenital birth defects including microcephaly in the developing fetus. Because development of a ZIKV vaccine is a top research priority and because the genetic and antigenic variability of many RNA viruses limits the effectiveness of vaccines, assessing whether immunity elicited against one ZIKV strain is sufficient to confer broad protection against all ZIKV strains is critical. Recently, in vitro studies demonstrated that ZIKV likely circulates as a single serotype. Here, we demonstrate that immunity elicited by African lineage ZIKV protects rhesus macaques against subsequent infection with Asian lineage ZIKV.Methodology/Principal FindingsUsing our recently developed rhesus macaque model of ZIKV infection, we report that the prototypical ZIKV strain MR766 productively infects macaques, and that immunity elicited by MR766 protects macaques against heterologous Asian ZIKV. Furthermore, using next generation deep sequencing, we found in vivo restoration of a putative N-linked glycosylation site upon replication in macaques that is absent in numerous MR766 strains that are widely being used by the research community. This reversion highlights the importance of carefully examining the sequence composition of all viral stocks as well as understanding how passage history may alter a virus from its original form.Conclusions/SignificanceAn effective ZIKV vaccine is needed to prevent infection-associated fetal abnormalities. Macaques whose immune responses were primed by infection with East African ZIKV were completely protected from detectable viremia when subsequently rechallenged with heterologous Asian ZIKV. Therefore, these data suggest that immunogen selection is unlikely to adversely affect the breadth of vaccine protection, i.e., any Asian ZIKV immunogen that protects against homologous challenge will likely confer protection against all other Asian ZIKV strains.

Infection via mosquito bite alters Zika virus replication kinetics in rhesus macaques

“…To assess differences in ZIKV replication between virus delivery by needle 73 versus mosquito vector, we infected rhesus macaques with the Puerto Rican ZIKV isolate 74 PRVABC59 by either sc inoculation (n=3) or by exposure to infected mosquitoes (n=4). All three 75 sc-inoculated macaques were productively infected, with viral load dynamics similar to what we 76 have reported previously 1,2 . All four animals exposed to Ae.…”

“…Zika virus (ZIKV; Flaviviridae, Flavivirus) is primarily transmitted by Aedes aegypti mosquitoes, 19 but animal models of ZIKV pathogenesis have relied on needle inoculation [1][2][3][4][5][6][7] . Needle 20 inoculation has been performed using a range of doses, delivered subcutaneously at a single 21 site or at multiple sites, as well as intravenously, intravaginally, intrarectally, and intra-22 amniotically in pregnant animals.…”

“…46 The amount of ZIKV inoculated by mosquitoes into a host is not known. In the majority of our 47 previous studies we used an inoculum dose of 1 x 10 4 PFU injected subcutaneously (sc) 1,2,24 , 48 which we chose as a dose likely to be delivered by a ZIKV-infected mosquito. This was based 49 on previous studies, which found that mosquitoes delivered ~1 x 10 4 -1 x 10 6 PFU of West Nile 50 virus (WNV) 12 and as much as 1 x 10 4 50% mosquito infectious doses of dengue virus (DENV) 51 25 .…”

Animal Models of Zika Virus Infection, Pathogenesis, and Immunity

“…These studies support the use of rhesus and cynomolgus macaques as models for improving our understanding of the cellular and tissue tropism of ZIKV infection. Infected rhesus macaques also developed ZIKV-specific humoral and cell-mediated immune responses (38,(87)(88)(89) that protected against challenge with homologous and heterologous viruses (87)(88)(89), indicating that this model will be useful for the evaluation of ZIKV adaptive immunity.…”

“…(i) Pathogenesis in immunocompetent adult macaques. Nonhuman primates (NHPs) also are being used to evaluate aspects of ZIKV biology and pathogenesis (38,(87)(88)(89)(90). Several groups have characterized ZIKV infection in pregnant and nonpregnant rhesus, cynomolgus, and pigtail macaques.…”