Characterization of the contemporary Zika virus in immunocompetent mice

Abstract

Zika virus (ZIKV) has raised global public health concerns due to its rapid transmission and unexpected clinical manifestations. 1 No vaccine or antiviral treatment is currently available, and the development of animal model of ZIKV infection is of priority. 2,3 The mouse model of ZIKV infection was recently developed using A129 and AG129 mice. [4][5][6][7] However, both mice are deficient in critical innate immune signaling, and more importantly, these animals are limited resource, and are not available for most labs in ZIKVendemic areas. Thus, a more relevant animal mode in immunocompetent animals is urgently needed. 8 Here, we establish an immunocompetent murine model using a contemporary American ZIKV strain GZ01 (GenBank nos. KU740184) that was isolated from a patient returned from Venezuela in 2016.9 ZIKV stocks were propagated in mosquito C6/36 cells and titrated by plaque forming assay on BHK-21 cells. 10We firstly inoculated 4-week-old 129Sv/Ev male mice with 10 5 PFU of ZIKV by the intraperitoneal (ip) route. Upon infection, no animal showed any clinical signs and all survived with a gradual increase on body weight (Fig. 1A). Transient viremia were observed by RT-qPCR assay, peaked at day 1 post infection (pi) and decreased below detection limit at day 3 pi (Fig. 1B). At days 1, 2 and 3 pi, mice were anesthetized and selected organs were dissected for RT-qPCR assay. The results showed that viral RNAs were disseminated into all tested organs at day 1 pi and the highest viral RNA loads were detected in testis, which was similar to that in A129 mice. 4 At day 3 pi, viral RNAs were cleared in most tissues except for spleen and testis (Fig. 1C). Additionally, hematoxylin and eosin staining showed that no obvious histological lesions were observed in brain, heart, kidney and testis tissues at day 1 pi. Slight loose deformation of liver cells with focal necrosis and partial central venous dilatation were found in liver, and multinucleated giant cells were observed within the membrane and red pulp of spleen (Fig. 1D). Similar viremia and viral RNA kinetics were also observed in ZIKV-infected Balb/C mice (data not shown).Further, to utilize the animal model described here for potential antiviral tests, the therapeutic effects of human convalescent phase serum 9 with the neutralization antibody titer of 1/80 were assayed. Briefly, group of 129Sv/Ev mice infected with 10 5 PFU of ZIKV were administrated ip with 150 ml of antibody at 4 and 24 h pi, and mock group were treated with PBS control. Blood was collected for viremia and autopsy were performed for viral dissemination. The result showed that passive transfer of convalescent phase serum completely eliminated viremia at day 1 and 2 in all ZIKV-infected mice compared with mock treatment (Fig. 1E). Importantly, viral RNAs were undetectable in the indicated organs (spleen and testis) in mice treated with convalescent phase serum (Fig. 1F).Finally, we tested the infectivity of ZIKV in 8-week-old 129 Sv/Ev mice. The result showed that that ZIKV could also cause sh...

Zika Virus Infection in Tupaia belangeri Causes Dermatological Manifestations and Confers Protection against Secondary Infection

“…5A). The highest viral load was observed in the testes, consistent with observations in other animal models (17,32). Then, we performed immunostaining of testis tissue with convalescence serum from a recovered ZIKV patient (33).…”

25-Hydroxycholesterol Protects Host against Zika Virus Infection and Its Associated Microcephaly in a Mouse Model

“…As our in vitro data indicated that 25HC promoted anti-viral activity against ZIKV, we next tested the in vivo antiviral effects of 25HC in 3- to 4-week-old immunocompetent BALB/c mice as described previously (Larocca et al, 2016; Zhang et al, 2016). Animals were treated with 25HC (50 mg/kg) or vehicle and infected with ZIKV strain GZ01/2016 intraperitoneally (i.p.).…”

Existing drugs as broad-spectrum and potent inhibitors for Zika virus by targeting NS2B-NS3 interaction

“…In the viremia model [39,40], temoporfin treatment resulted in about 100-fold reduction in ZIKV-induced viremia in immunocompetent Balb/C mice compared to the vehicle control ( Figure 5A). In the lethal A129 mouse model [41,42], all the ZIKV-infected animals treated with vehicle died with typical neurological symptoms including hind limb weakness and paralysis.…”

“…For the viremia model in immunocompetent Balb/C mice [39,40], a group of 3-week-old female Balb/c mice infected intraperitoneally (ip) with 2 × 10 5 PFU of ZIKV strain GZ01/2016 were ip administered temoporfin at 0.02 mg/mice (n = 8) or vehicle control (n = 7) every day for 2 consecutive days post infection (dpi). Viremia on day 2 pi was determined by RT-qPCR, and statistical analysis was performed using the unpaired, two-tailed t-test.…”