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1.
Nat Commun ; 14(1): 1394, 2023 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-36914633

RESUMO

Human epidermal growth factor receptor 2 (HER2) is a receptor tyrosine kinase that plays an oncogenic role in breast, gastric and other solid tumors. However, anti-HER2 therapies are only currently approved for the treatment of breast and gastric/gastric esophageal junction cancers and treatment resistance remains a problem. Here, we engineer an anti-HER2 IgG1 bispecific, biparatopic antibody (Ab), zanidatamab, with unique and enhanced functionalities compared to both trastuzumab and the combination of trastuzumab plus pertuzumab (tras + pert). Zanidatamab binds adjacent HER2 molecules in trans and initiates distinct HER2 reorganization, as shown by polarized cell surface HER2 caps and large HER2 clusters, not observed with trastuzumab or tras + pert. Moreover, zanidatamab, but not trastuzumab nor tras + pert, elicit potent complement-dependent cytotoxicity (CDC) against high HER2-expressing tumor cells in vitro. Zanidatamab also mediates HER2 internalization and downregulation, inhibition of both cell signaling and tumor growth, antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP), and also shows superior in vivo antitumor activity compared to tras + pert in a HER2-expressing xenograft model. Collectively, we show that zanidatamab has multiple and distinct mechanisms of action derived from the structural effects of biparatopic HER2 engagement.


Assuntos
Anticorpos Biespecíficos , Antineoplásicos , Neoplasias da Mama , Humanos , Feminino , Ensaios Antitumorais Modelo de Xenoenxerto , Linhagem Celular Tumoral , Trastuzumab/farmacologia , Trastuzumab/uso terapêutico , Receptor ErbB-2/metabolismo , Citotoxicidade Celular Dependente de Anticorpos , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico
2.
J Biol Chem ; 287(22): 18078-90, 2012 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-22493450

RESUMO

A self-consistent model of ß-mannan oligosaccharides bound to a monoclonal antibody, C3.1, that protects mice against Candida albicans has been developed through chemical mapping, NMR spectroscopic, and computational studies. This antibody optimally binds di- and trisaccharide epitopes, whereas larger oligomers bind with affinities that markedly decrease with increasing chain length. The (1→2)-ß-linked di-, tri-, and tetramannosides bind in helical conformations similar to the solution global minimum. Antibody recognition of the di- and trisaccharide is primarily dependent on the mannose unit at the reducing end, with the hydrophobic face of this sugar being tightly bound. Recognition of a tetrasaccharide involves a frameshift in the ligand interaction, shown by strong binding of the sugar adjacent to the reducing end. We show that frameshifting may also be deliberately induced by chemical modifications. Molecular recognition patterns similar to that of mAb C3.1, determined by saturation transfer difference-NMR, were also observed in polyclonal sera from rabbits immunized with a trisaccharide glycoconjugate. The latter observation points to the importance of internal residues as immunodominant epitopes in (1→2)-ß-mannans and to the viability of a glycoconjugate vaccine composed of a minimal length oligosaccharide hapten.


Assuntos
Anticorpos Monoclonais/imunologia , Candida albicans/metabolismo , Mananas/imunologia , Sequência de Carboidratos , Simulação por Computador , Epitopos Imunodominantes/química , Epitopos Imunodominantes/imunologia , Mananas/química , Mananas/metabolismo , Modelos Moleculares , Simulação de Dinâmica Molecular , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular
3.
Mol Immunol ; 47(7-8): 1529-34, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20153529

RESUMO

The use of recombinant antibody fragments (rAbF) as therapeutic agents is compromised by shorter serum persistences than IgG therapeutics and their inability to mediate Fc-dependent effector functions. Here, we show that the strategy of complex formation between epitope-tagged rAbFs and anti-epitope IgG monoclonal antibodies (mAb) can improve the therapeutic potential of rAbFs by both enhancing their serum persistence and conferring on them the ability to recruit Fc-mediated effector functions. These two mechanistic aspects of this strategy were demonstrated using c-myc- and 6xHis-tagged Fab and scFv rAbFs, both directed against Pseudomonas aeruginosa O6ad, in combination with two different murine anti-epitope tag IgGs, anti-5xHis IgG (Penta-His) and anti-c-myc IgG (9E10). Further enhancement of this strategy for the employment of rAbFs as therapeutics is discussed.


Assuntos
Anticorpos Anti-Idiotípicos/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Epitopos/imunologia , Fragmentos de Imunoglobulinas/uso terapêutico , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/imunologia , Animais , Anticorpos Anti-Idiotípicos/imunologia , Anticorpos Monoclonais/imunologia , Linhagem Celular , Fragmentos de Imunoglobulinas/imunologia , Camundongos , Infecções por Pseudomonas/imunologia , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/uso terapêutico
4.
Biotechnol Adv ; 27(4): 502-20, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19374944

RESUMO

Antibodies (Abs) are some of the most powerful tools in therapy and diagnostics and are currently one of the fastest growing classes of therapeutic molecules. Recombinant antibody (rAb) fragments are becoming popular therapeutic alternatives to full length monoclonal Abs since they are smaller, possess different properties that are advantageous in certain medical applications, can be produced more economically and are easily amendable to genetic manipulation. Single-chain variable fragment (scFv) Abs are one of the most popular rAb format as they have been engineered into larger, multivalent, bi-specific and conjugated forms for many clinical applications. This review will show the tremendous versatility and importance of scFv fragments as they provide the basic antigen binding unit for a multitude of engineered Abs for use as human therapeutics and diagnostics.


Assuntos
Fragmentos de Imunoglobulinas , Região Variável de Imunoglobulina , Engenharia de Proteínas/métodos , Fragmentos de Imunoglobulinas/biossíntese , Fragmentos de Imunoglobulinas/química , Fragmentos de Imunoglobulinas/uso terapêutico , Região Variável de Imunoglobulina/química , Região Variável de Imunoglobulina/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/uso terapêutico
5.
Vaccine ; 25(23): 4611-22, 2007 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-17481782

RESUMO

Peptide mimotopes have been investigated as surrogate antigens of carbohydrate (CHO) targets on pathogen and tumor cells in vaccine and therapeutic discovery. One of the main bottlenecks in peptide mimotope discovery is the inability of initial screening regimes to differentiate between true mimotopes and non-mimotopes. As a result, subsequent in vivo analysis of putative peptide mimotopes is often inefficient requiring the use of experimental animals during a lengthy in vivo immunization process. Here, we demonstrate a rapid preliminary screening method to identify putative mimotopes using a recombinant antibody (rAb) library, which may increase the probability of identifying peptides that will elicit a CHO-cross-reactive response in vivo. A human naïve rAb library was screened against both an established peptide mimotope and a non-mimotope of the Group B Streptococcus (GBS) type III polysaccharide to determine if selected antibodies cross-reacted with the original GBS polysaccharide. We were able to differentiate between these two peptides because peptide-binding Abs that cross-reacted to GBS was isolated only with the peptide mimotope. We discuss the feasibility of using this method to significantly increase the breadth of screening and reduce the discovery time for peptide mimotopes.


Assuntos
Anticorpos/imunologia , Antígenos de Bactérias/imunologia , Biblioteca de Peptídeos , Polissacarídeos Bacterianos/imunologia , Streptococcus agalactiae/imunologia , Sequência de Aminoácidos , Humanos , Dados de Sequência Molecular , Probabilidade , Proteínas Recombinantes/imunologia
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