1 g/mL) ( Figure?3A ; Supplementary Number?3 ). anti-S1-RBD IgG. Passive transfer anti-S1-RBD IgG into mice also reduced prolonged bleeding time and decreased NS1 seral TMOD4 level in DENV-infected mice. Lastly, COVID-19 individuals sera showed neutralizing ability against dengue illness and prevent DENV-induced long term bleeding time and decreased NS1seral level in mice. Last, an increase in antibody binding to DENV-related antigens was also found in some individuals after SARS-CoV-2 illness. Furthermore, DENV illness was inhibited in the presence of COVID-19 patients but not healthy controls sera. Therefore, our results suggest anti-SARS-CoV-2 antibodies induced during SARS-CoV-2 illness may interfere with DENV illness, which should become further evaluated in clinical study. Materials and methods Recombinant proteins and peptides DENV serotype 2 E, prM and NS4B recombinant proteins were indicated and purified from (Leadgene Biomedical Inc., Tainan, Taiwan). SARS-CoV-2 trimeric spike and nucleocapsid protein purified from HEK293 cells and human being ACE2-Fc recombinant protein purified from CHO cells were provided by Leadgene organization (Cat. No. 63233, 61633 and 63333). The synthetic peptides were customized, purified and synthesized by Leadgene organization. DENV serotype 2 (strain Thailand/16681/84) NS1 recombinant protein produced in mammalian HEK293 cells was purchased from The Native Antigen Organization (Oxfordshire, UK). Human being serum Dengue patient sera were collected from National Cheng Kung University or college Hospital (NCKUH) in the acute stage of the disease during a DENV outbreak in Tainan, Taiwan, in 2015 (25). In addition, sera from 29 healthy donors were included as bad settings. All serum selections were performed in accordance with the relevant recommendations and regulations authorized by the institutional review table of NCKUH (IRB #A-BR-101C140). SARS-CoV-2 antibody positive sera were purchased from Access Biologicals (Vista, CA), and the detailed information was demonstrated in the supplementary table of our earlier study (26). According to the manufacturers documentation, the samples were collected in the U.S. in June 2020 from 30 COVID-19 individuals (19 belong to the race of Caucasian, 10 African American, and one unfamiliar) who have been confirmed of illness during March to April 2020. The commercial COVID-19 individual sera were dispensed inside a Biosafety Level-2 Plus (BSL-2+) laboratory by fully qualified individuals according to the compliance guidelines of NCKUH. Dispensed individual sera were inactivated at 56C for 30?min before Zaurategrast (CDP323) being used in this study. Cell lines The cell collection (C6/36) and baby hamster kidney cell collection (BHK-21), managed in Dulbeccos altered Eagles medium (DMEM) supplemented with 10% fetal bovine serum (FBS, HyClone, Logan, UT), were purchased from your American Type Tradition Collection (ATCC, Manassas, VA) and Japanese Collection of Study Bioresources (Japan), respectively. The cell collection (S2) purchased from ATCC was managed in Schneiders Drosophila Medium (SERVA Electrophoresis GmbH, Heidelberg, Germany) supplemented with 10% FBS. The human being microvascular endothelial cell collection (HMEC-1) was from the Center for Disease Control and Prevention (CDC, Taiwan) and was cultured in Medium 200 (Thermo Fisher Scientific, Waltham, MA) supplemented Zaurategrast (CDP323) with 10% FBS. Human being monocytic cell collection (THP-1) was produced in RPMI 1640 medium with 10% FBS. Except for S2 cells and C6/36 cells, which were cultured at 27?C without CO2 incubation and at 27? C inside a 5% CO2 atmosphere, respectively, the additional cells were cultured at 37?C inside a 5% CO2 atmosphere. Viral stocks The DENV serotype 2 strain 16681 or 454009A was propagated in C6/36 cells as previously explained (27). To obtain high titers of DENV, we used a Macrosep Advance Centrifugal Device (MW cutoff of 30 kDa; Pall Corp., Slot Washington, NY) to concentrate the DENV-containing medium centrifugation at 6000g at 4C, and the concentrated DENV was stored below ?70C until use. Manifestation and purification of SARS-CoV-2 S1-RBD Zaurategrast (CDP323) recombinant protein For the manifestation and purification of SARS-CoV-2 S1-RBD recombinant protein, SARS-CoV-2 S1-RBD from a.a. 319 to 541 (“type”:”entrez-protein”,”attrs”:”text”:”YP_009724390″,”term_id”:”1796318598″,”term_text”:”YP_009724390″YP_009724390) was cloned into pMT/BiP/V5-His B plasmid for the manifestation in S2 cells ( Supplementary Number?1 ). In brief, pMT-S1-RBD, comprising 2x strep and 6x histidine, was transfected into S2 cells and induced with 500 M CuSO4. After four days of Zaurategrast (CDP323) induction, S1-RBD protein in the supernatant was purified by Strep-Tactin Superflow Plus (QIAGEN GmbH, Hilden, Germany). 2.6 mg of S1-RBD protein were purified from a 500 mL induction medium. The purity of SARS-CoV-2 S1-RBD from S2 cell Zaurategrast (CDP323) was checked using SDS-PAGE and western blotting with anti-His antibody (Cat. No. 10411, Leadgene Biomedical Inc.). Human being ACE2 binding ability of the.