Since the amino acid sequence of the humanized scFv was carefully designed and was found to be highly similar to human Ibrutinib supply sequences, we believe that we efficiently removed all major immunogenic epitopes on the murine antibody. However, the actual immunogenicity could only be determined in clinical trials. Immunotherapy based on anti-PrP antibodies is a promising strategy for the treatment of prion diseases. It has already been shown that some anti-PrP mAbs can antagonize prion propagation in vitro and in vivo, but only outside the brain, most likely due to very limited entry of large molecules into the central nervous system. Single-chain fragments are much smaller than whole antibodies, but usually they retain specific monovalent antigen-binding affinity of the parent antibody, with improved pharmacokinetics for tissue penetration. Antibody fragments have already been reported to be successfully delivered to the central nervous system by intranasal administration, by virus-mediated gene transfer system or by re-engineering as fusion proteins with BBB molecular Trojan horses. Besides, antibody fragments appear to be more appropriate for TSE treatment than full antibodies, since bivalent anti-PrP antibodies have been shown to cross-link PrPC molecules and trigger neuronal apoptosis in certain neuronal populations. It was also demonstrated that constant domains are unnecessary for antiprion effect, since Fab D18, scFv 6H4 and scFv D18 all exhibited antiprion activity. A construct that targets PrPSc specifically could even be more efficient. Moreover, distinguishing between the pathological and the normal isoform of PrP is one of the most desirable properties of diagnostic tools for prion diseases. Based on the existing knowledge it can be concluded that small molecules, exhibiting high affinity binding of the pathological PrP isoform, such as our humanized scFv V5B2, might be a potential therapeutic reagent for TSEs. The Filoviridae family contains the Ebola and Marburg viruses. These are enveloped viruses composed of seven genes which encode eight proteins in the Ebola virus and seven in the Marburg virus. The single-stranded negative-sense RNA genome is encased in a nucleocapsid complex, which consists of the following four viral proteins: the nucleoprotein, the viral proteins and the polymerase. This complex is surrounded by a matrix consisting of VP40 and VP24, which is packaged by a lipid membrane envelope obtained during budding from the host cell. The envelope is composed of the GP protein, which is post-translationally cleaved by a furin protease into two fragments, GP1 and GP2, although this cleavage is not necessary for in vitro viral infection of cells. A disulfide bridge in the mature molecule connects these subunits. GP1 is responsible for interaction with its cellular receptor, and GP2 is involved in the mechanism of membrane fusion. Membrane fusion is a common feature among enveloped viruses and is an important part of the viral infection cycle.