The former Soviet Union developed a live attenuated vaccine against that prevented infection, but did not have therapeutic efficacy [5]. throughout recorded human history, and novel prophylactics and therapeutics are necessary given its potential as a bioweapon. Only one monoclonal antibody Flurbiprofen has been identified to Flurbiprofen date that provides total protection against 141 contamination when administered prophylactically to Balb/c mice (100 g intravenously). We humanized F2H5, characterized its ability to bind to the F1 protein and further characterized the neutralizing epitope using computational and experimental methods. While Western blot results suggested a linear epitope, peptide mapping using ELISA failed to identify an epitope, suggesting a conformational epitope instead. We adopted a computational approach based ANK2 on Residue Contact Frequency Flurbiprofen to predict the site of antigen-antibody conversation and defined the F2H5/F1 binding site computationally. Based on computational approach, we decided that residues G104E105N106 in F1 were crucial to F2H5 binding and that CDRH2 and CDRH3 of F2H5 interacted with F1. Our results show that combining computational approach and experimental approach can effectively identify epitopes. Introduction (is usually difficult to eradicate because animal reservoirs exist worldwide. According to a Flurbiprofen World Health Business (WHO) report, between January 2010 and December 2015, there were 3,248 cases of contamination worldwide with a mortality rate of 17.98% [2]. also has the potential for using as an aerosolized bioweapon and is recognized as a category A agent around the National Institute of Allergy and Infectious Diseases (NIAID) list of biodefense-related pathogens [3]. The first collection antibiotics for treatment of are streptomycin, tetracycline, and chloramphenicol, while the first collection prophylactics are sulfonamide, trimethoprim-sulfamethoxazole, or tetracycline. A strain of with resistance to all of the antimicrobial brokers recommended for treatment and prophylaxis was isolated in 1995 in Madagascar from a 16-year-old male presenting with symptoms of bubonic plague. The isolates drug resistance was mediated by a self-transferable plasmid, raising the potential for wider dissemination and a possible threat to global public health [4]. The former Soviet Union developed a live attenuated vaccine against that prevented contamination, but did not have therapeutic efficacy [5]. Monoclonal antibodies (mAbs), such as PAmAb and ETIi204 targeting has focused on the Portion 1 Capsular Antigen (F1) [8C10]. The low-calcium-response V antigen (LcrV) and other antigens have been investigated as vaccine targets [11C13], but the results were not encouraging. In murine models, three mAbs against F1, F1-04-A-G1, F1-08-D-G1 and YPF1-6H3-1-1, have guarded 60%-100% of mice challenged subcutaneously with [14]. In addition, a human F1 specific mAb (M252) has been isolated that results in approximately 33% survival in an in vivo challenge model [15]. To date only, F1-04-A-G1 has shown to provide total protection. These results suggest that there is at least one crucial neutralizing epitope in the F1 protein. However, the number of protective epitopes in the F1 protein is not yet known and the epitope recognized by F1-04-A-G1 has not been reported. M252 has been reported to bind weakly to the immunodominant peptide in F1 (amino acids 142C165), but regrettably, this epitope is not neutralizing [15]. Here, we describe a mAb (F2H5) from a mouse hybridoma that provides complete protection in a mouse contamination model. We also characterized the binding epitope using computational algorithms for predicting complex structures and binding sites when experimental methods failed. By this method, we identify the epitope successfully. Materials and methods Ethics statement All the animal experiments in this study were approved by the Laboratory Animal Care and Use Committee of Beijing Institute of Biotechnology. Flurbiprofen All surgery was performed under sodium pentobarbital anesthesia and mice were sacrificed at indicated time by CO2 inhalation. All efforts were made to minimize the suffering. Cultivation of virulent (141) was isolated from around the Qinghai-Tibet plateau by Qinghai Institute for Endemic Disease Prevention and Control [16]. 141 (Sample ID:.