Antibody acknowledgement and neutralization determinants on domains I and II of West Nile computer virus envelope protein. the amino acid level by 25 to 40%. Additional complexity occurs within each serotype, as genotypes vary from one another by up to 3% at the amino acid level (21, 49). No approved antiviral treatment is currently available, and several GSK2190915 candidate tetravalent vaccines remain in clinical development (examined in reference 11). Because of the increased geographic range of its mosquito vectors, urbanization, and international travel, DENV continues to spread worldwide and now causes an estimated 50 to 100 million infections and 250,000 to 500,000 cases of DHF/DSS per year, with 2.5 billion people at risk (68). DENV is an enveloped icosahedral computer virus with a single-stranded, positive-polarity RNA genome. The 10.7-kb genome is usually translated as a single polyprotein, which is usually cleaved into three structural proteins (capsid [C], premembrane/membrane [prM/M], and envelope [E]) and seven nonstructural (NS) proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) by host and viral proteases. The mature DENV virion is usually 500 ? in diameter, with a highly organized outer protein shell, a 50-? B2M lipid membrane bilayer, and a nucleocapsid core (26). Mature DENV virions are covered by 90 anti-parallel E protein homodimers, arranged smooth along the surface with quasi-icosahedral symmetry. The immature virion, which lacks cleavage of the prM protein, has a rough surface with 60 spikes each composed of three prM-E heterodimers (7, 73). Exposure to GSK2190915 mildly acidic conditions in the inhibitory activity of MAbs in cells against a genetically diverse range of DENV-2 strains and their protective capacity in animals. Here, we had the goal of generating strongly neutralizing MAbs that would recognize virtually all DENV-2 strains and function as a possible postexposure therapy. Twenty-four new anti-DENV-2 mouse MAbs were generated with moderate or strong neutralizing activity against the homologous computer virus in cell culture assays. Binding sites were mapped for the majority of these by yeast surface display, identifying unique epitopes in regions in DI (lateral ridge), DII (dimer interface, lateral ridge, and fusion loop), and DIII (lateral ridge, C-C loop, and A strand). Several MAbs failed to neutralize efficiently at least one DENV-2 strain of a distinct genotype, suggesting that antibody acknowledgement of neutralizing epitopes varies among DENV-2 genotypes. To begin to assess the utility of this new panel of inhibitory MAbs as you possibly can therapeutics against DENV-2, we evaluated their protective capacity in a stringent intracranial challenge model in BALB/c mice. Among the 16 neutralizing MAbs tested in mice, most were protective when given as prophylaxis. Seven of these had postexposure therapeutic activity when administered as a single dose by intraperitoneal route even 3 days after intracranial contamination. For the MAbs with the greatest therapeutic potential, protection was confirmed with an antibody-enhanced vascular leakage mouse model (2, 72) of DENV-2 contamination. MATERIALS AND METHODS Cells and viruses. BHK21 and HEK-293T cells were cultured in Dulbecco’s altered Eagle medium (DMEM) supplemented with 10% fetal bovine serum (FBS) (Omega Scientific) and antibiotics (penicillin G and streptomycin). Raji-DC-SIGN-R cells were cultured in RPMI-1640 GSK2190915 medium supplemented with 10% FBS and antibiotics. DENV-2 strains used in this study included 16681 (Southeast Asian genotype), C0477 (Southeast Asian genotype), New Guinea C (NGC) (Southeast Asian genotype), D2S10 (Southeast Asian genotype), ArA6894 (Indian genotype), IQT2913 (American genotype), and PM33974 (West African genotype). DENV strains from other serotypes were obtained from colleagues (A. de Silva, University or college of North Carolina, and R. Tesh, University or college of Texas Medical Branch) and included 16007 (DENV-1), 16652 (DENV-3), and 1036 (DENV-4). All viruses were propagated in C6/36 cells according to explained protocols (57). E gene sequencing. The computer virus nucleotides from positions 616 to 2578 were amplified by reverse transcription (RT)-PCR using a high-fidelity polymerase and RNA extracted directly from infected C6/36 cells. Each amplicon was sequenced on both strands by standard capillary sequencing on an Applied Biosystems 310 genetic analyzer using previously reported primers (28). The producing sequence reads were assembled, and the E gene sequences aligned using the Lasergene suite (DNASTAR). Generation, purification, and labeling of anti-DENV-2 MAbs. To generate anti-DENV-2 MAbs, alpha/beta interferon receptor-deficient (IFN-/R?/?) C57BL/6 mice were infected with 105 PFU of a mixture (1:1) of DENV-2 strains 16681 and NGC via an intraperitoneal route and rechallenged.