Zika Virus Infection in Dexamethasone-immunosuppressed Mice Demonstrating Disseminated Infection with Multi-organ Involvement Including Orchitis Effectively Treated by Recombinant Type I Interferons

Chan, Jasper Fuk-Woo; Zhang, Anna Jinxia; Chan, Chris Chung-Sing; Yip, Cyril Chik-Yan; Mak, Winger Wing-Nga; Zhu, Houshun; Poon, Vincent Kwok-Man; Tee, Kah-Meng; Zhu, Zheng; Cai, Jian-Piao; Tsang, Jessica Oi-Ling; Chik, Kenn Ka-Heng; Yin, Feifei; Chan, Kwok-Hung; Kok, Kin-Hang; Jin, Dong-Yan; Au-Yeung, Rex Kwok-Him; Yuen, Kwok-Yung

For immunohistochemical staining of ZIKV-NS1 antigen, mouse antiserum against ZIKV-NS1 protein prepared as we previously described was used as primary antibody (Chan et al., 2016b) . De-paraffinized and rehydrated tissue sections were treated with Antigen Unmasking Solution according to manufacturer's instructions (Vector Laboratories Inc., Burlingame, CA, USA) and then stained with Mouse on Mouse Polymer IHC kit (Abcam, Cambridge, United Kingdom). The primary antibody mouse anti-ZIKV-NS1 antiserum (1:1000 dilution with 1% BSA/PBS) was incubated at 4°C overnight. This was followed by Mouse on Mouse HRP polymer kit (Abcam) with horseradish peroxidase-conjugated secondary antibody for 15 min. Color development was performed using 3,3′-diaminobenzidine (DAB) (Vector Laboratories, Burlingame, CA, USA). For immunohistochemical staining of CD45 and CD8, the sections were incubated at 4°C for overnight with primary antibody (rabbit anti-mouse CD45, or rat anti-mouse CD8α (Abcam) after antigen unmasking and blocking. This was then followed by incubation with biotin-conjugated goat anti-rabbit IgG or goat anti-rat IgG (Calbiochem, Darmstadt, Germany) for 30 min at room temperature. Streptavidin/peroxidase complex reagent (Vector Laboratories) was then added and incubated at room temperature for 30 min. Color development was done with DAB (Vector Laboratories). All tissue sections were examined microscopically by two pathologists in an operatorblinded manner. Images were captured with Nikon80i imaging system equipped with Spot-advance computer software.