A Human Antibody Fragment with High Affinity for Biodegradable Polymer Film

2007 ◽  
Vol 18 (3) ◽  
pp. 645-651 ◽  
Author(s):  
Hideki Watanabe ◽  
Kouhei Tsumoto ◽  
Seiichi Taguchi ◽  
Koichi Yamashita ◽  
Yoshiharu Doi ◽  
...  
Keyword(s):  
Polymer Film ◽  
Biodegradable Polymer ◽  
Antibody Fragment ◽  
Human Antibody ◽  
High Affinity

A High-Affinity Human Antibody That Targets Tumoral Blood Vessels

Blood ◽  
1999 ◽  
Vol 94 (1) ◽  
pp. 192-198 ◽  
Author(s):  
Lorenzo Tarli ◽  
Enrica Balza ◽  
Francesca Viti ◽  
Laura Borsi ◽  
Patrizia Castellani ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Small Cell Lung Carcinoma ◽  
Antibody Fragment ◽  
Human Colon ◽  
Experimental Models ◽  
Human Antibody ◽  
Cell Lung Carcinoma ◽  
High Affinity ◽  
Biodistribution Studies

Angiogenesis is a characteristic feature of many aggressive tumors and of other relevant disorders. Molecules capable of specifically binding to new-forming blood vessels, but not to mature vessels, could be used as selective vehicles and would, therefore, open diagnostic and therapeutic opportunities. We have studied the distribution of the ED-B oncofetal domain of fibronectin, a marker of angiogenesis, in four different tumor animal models: the F9 murine teratocarcinoma, SKMEL-28 human melanoma, N592 human small cell lung carcinoma, and C51 human colon carcinoma. In all of these experimental models we observed accumulation of the fibronectin isoform containing the ED-B domain around neovascular structures when the tumors were in the exponentially growing phase, but not in the slow-growing phase. Then we performed biodistribution studies in mice bearing a subcutaneously implanted F9 murine teratocarcinoma, using a high-affinity human antibody fragment (L19) directed against the ED-B domain of fibronectin. Radiolabeled L19, but not an irrelevant anti-lysozyme antibody fragment (D1.3), efficiently localizes in the tumoral vessels. The maximal dose of L19 accumulated in the tumor was observed 3 hours after injection (8.2% injected dose per gram). By virtue of the rapid clearance of the antibody fragment from the circulation, tumor-to-blood ratios of 1.9, 3.7, and 11.8 were obtained at 3, 5, and 24 hours, respectively. The tumor-targeting performance of L19 was not dose-dependent in the 0.7 to 10 μg range of injected antibody. The integral of the radioactivity localized in tumoral vessels over 24 hours was greater than 70-fold higher than the integral of the radioactivity in blood over the same time period, normalized per gram of tissue or fluid. These findings quantitatively show that new-forming blood vessels can selectively be targeted in vivo using specific antibodies, and suggest that L19 may be of clinical utility for the immunoscintigraphic detection of angiogenesis in patients.

scholarly journals High-Affinity, Human Antibody-Like Antibody Fragment (Single-Chain Variable Fragment) Neutralizing the Lethal Factor (LF) of Bacillus anthracis by Inhibiting Protective Antigen-LF Complex Formation

2007 ◽  
Vol 51 (8) ◽  
pp. 2758-2764 ◽  
Author(s):  
Thibaut Pelat ◽  
Michael Hust ◽  
Emmanuelle Laffly ◽  
Florence Condemine ◽  
Chantal Bottex ◽  
...  
Keyword(s):  
Protective Antigen ◽  
Germ Line ◽  
Lethal Factor ◽  
Antibody Fragment ◽  
Human Antibody ◽  
Single Chain Variable Fragment ◽  
Single Chain ◽  
Vitro Assay ◽  
High Affinity

ABSTRACT The anthrax lethal toxin (LT) consists of two subunits, the protective antigen (PA) and the lethal factor (LF), and is essential for anthrax pathogenesis. Several recombinant antibodies directed against PA and intended for medical use have been obtained, but none against LF, despite the recommendations of anthrax experts. Here we describe an anti-LF single-chain variable fragment (scFv) that originated from an immunized macaque (Macaca fascicularis) and was obtained by phage display. Panning of the library of 1.8 × 108 clones allowed the isolation of 2LF, a high-affinity (equilibrium dissociation constant, 1.02 nM) scFv, which is highly neutralizing in the standardized in vitro assay (50% inhibitory concentration, 1.20 ± 0.06 nM) and in an in vivo assay. The scFv neutralizes anthrax LT by inhibiting the formation of the LF-PA complex. The genes encoding 2LF are very similar to those of human immunoglobulin germ line genes, sharing substantial (84.2%) identity with their most similar, germinally encoded counterparts; this feature favors medical applications. These results, and others formerly published, demonstrate that our approach can generate antibody fragments suitable for prophylaxis and therapeutics.

Selective targeting and photocoagulation of ocular angiogenesis mediated by a phage-derived human antibody fragment

10.1038/13679 ◽  
1999 ◽  
Vol 17 (10) ◽  
pp. 984-988 ◽  
Author(s):  
Manfred Birchler ◽  
Francesca Viti ◽  
Luciano Zardi ◽  
Bernhard Spiess ◽  
Dario Neri
Keyword(s):  
Antibody Fragment ◽  
Human Antibody ◽  
Ocular Angiogenesis ◽  
Selective Targeting

scholarly journals Structure-Based Modification of an Anti-neuraminidase Human Antibody Restores Protection Efficacy against the Drifted Influenza Virus

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Haihai Jiang ◽  
Weiyu Peng ◽  
Jianxun Qi ◽  
Yan Chai ◽  
Hao Song ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Influenza Virus ◽  
Antibody Fragment ◽  
Salt Bridge ◽  
Cross Reactivity ◽  
Human Antibody ◽  
Influenza Strain ◽  
Group 2 ◽  
Fragment Antigen Binding ◽  
Group 1

ABSTRACT Here, we investigate a monoclonal antibody, Z2B3, isolated from an H7N9-infected patient, that exhibited cross-reactivity to both N9 (group 2) and a broad range of seasonal and avian N1 (group 1) proteins but lost activity to the N1 with the substitution K432E. This substitution exists in 99.25% of seasonal influenza strains after 2013. The NA-Z2B3 complex structures indicated that Z2B3 binds within the conserved active site of the neuraminidase (NA) protein. A salt bridge between D102 in Z2B3 and K432 in NA plays an important role in binding. Structure-based modification of Z2B3 with D102R in heavy chain reversed the salt bridge and restored the binding and inhibition of N1 with E432. Furthermore, Z2B3-D102R can protect mice from A/Serbia/NS-601/2014 H1N1 virus (NA contains E432) infection while the wild-type Z2B3 antibody shows no protection. This study demonstrates that a broadly reactive and protective antibody to NA can be in principle edited to restore binding and inhibition to recently drifted N1 NA and regain protection against the variant influenza strain. IMPORTANCE The immune system produces antibodies to protect the human body from harmful invaders. The monoclonal antibody (MAb) is one kind of effective antivirals. In this study, we isolated an antibody (Z2B3) from an H7N9 influenza virus-infected child. It shows cross-reactivity to both group 1 (N1) and group 2 (N9) neuraminidases (NAs) but is sensitive to N1 NA with a K432E substitution. Structural analysis of the NA-antibody fragment antigen-binding (Fab) complex provides a clue for antibody modification, and the modified antibody restored binding and inhibition to recently drifted N1 NA and regained protection against the variant influenza strain. This finding suggests that antibodies to NA may be a useful therapy and can be in principle edited to defeat drifted influenza virus.

scholarly journals Recognition of an α-helical hairpin in P22 large terminase by a synthetic antibody fragment

2020 ◽  
Vol 76 (9) ◽  
pp. 876-888
Author(s):  
Ravi K. Lokareddy ◽  
Ying-Hui Ko ◽  
Nathaniel Hong ◽  
Steven G. Doll ◽  
Marcin Paduch ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Conformational Changes ◽  
Recombinant Antibody ◽  
Antibody Fragment ◽  
Genome Packaging ◽  
Synthetic Antibody ◽  
High Affinity ◽  
N Terminus ◽  
Helical Hairpin ◽  
Accessible Surface

The genome-packaging motor of tailed bacteriophages and herpesviruses is a multisubunit protein complex formed by several copies of a large (TerL) and a small (TerS) terminase subunit. The motor assembles transiently at the portal protein vertex of an empty precursor capsid to power the energy-dependent packaging of viral DNA. Both the ATPase and nuclease activities associated with genome packaging reside in TerL. Structural studies of TerL from bacteriophage P22 have been hindered by the conformational flexibility of this enzyme and its susceptibility to proteolysis. Here, an unbiased, synthetic phage-display Fab library was screened and a panel of high-affinity Fabs against P22 TerL were identified. This led to the discovery of a recombinant antibody fragment, Fab4, that binds a 33-amino-acid α-helical hairpin at the N-terminus of TerL with an equilibrium dissociation constant K d of 71.5 nM. A 1.51 Å resolution crystal structure of Fab4 bound to the TerL epitope (TLE) together with a 1.15 Å resolution crystal structure of the unliganded Fab4, which is the highest resolution ever achieved for a Fab, elucidate the principles governing the recognition of this novel helical epitope. TLE adopts two different conformations in the asymmetric unit and buries as much as 1250 Å2 of solvent-accessible surface in Fab4. TLE recognition is primarily mediated by conformational changes in the third complementarity-determining region of the Fab4 heavy chain (CDR H3) that take place upon epitope binding. It is demonstrated that TLE can be introduced genetically at the N-terminus of a target protein, where it retains high-affinity binding to Fab4.

scholarly journals High Affinity Human Antibody Fragments to Dengue Virus Non-Structural Protein 3

2010 ◽  
Vol 4 (11) ◽  
pp. e881 ◽  
Author(s):  
Nicole J. Moreland ◽  
Moon Y. F. Tay ◽  
Elfin Lim ◽  
Prasad N. Paradkar ◽  
Danny N. P. Doan ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Antibody Fragments ◽  
Human Antibody ◽  
Structural Protein ◽  
High Affinity

Selective targeting of tumour neovasculature by a radiohalogenated human antibody fragment specific for the ED-B domain of fibronectin

2001 ◽  
Vol 28 (4) ◽  
pp. 534-539 ◽  
Author(s):  
Salvatore Demartis ◽  
Lorenzo Tarli ◽  
Laura Borsi ◽  
Luciano Zardi ◽  
Dario Neri
Keyword(s):  
Antibody Fragment ◽  
Human Antibody ◽  
Selective Targeting
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