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1.
Int J Mol Sci ; 25(10)2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38791489

RESUMO

The SARS-CoV-2 Omicron variants have replaced all earlier variants, due to increased infectivity and effective evasion from infection- and vaccination-induced neutralizing antibodies. Compared to earlier variants of concern (VoCs), the Omicron variants show high TMPRSS2-independent replication in the upper airway organs, but lower replication in the lungs and lower mortality rates. The shift in cellular tropism and towards lower pathogenicity of Omicron was hypothesized to correlate with a lower toll-like receptor (TLR) activation, although the underlying molecular mechanisms remained undefined. In silico analyses presented here indicate that the Omicron spike protein has a lower potency to induce dimerization of TLR4/MD-2 compared to wild type virus despite a comparable binding activity to TLR4. A model illustrating the molecular consequences of the different potencies of the Omicron spike protein vs. wild-type spike protein for TLR4 activation is presented. Further analyses indicate a clear tendency for decreasing TLR4 dimerization potential during SARS-CoV-2 evolution via Alpha to Gamma to Delta to Omicron variants.


Assuntos
COVID-19 , Antígeno 96 de Linfócito , Multimerização Proteica , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Receptor 4 Toll-Like , Receptor 4 Toll-Like/metabolismo , SARS-CoV-2/patogenicidade , SARS-CoV-2/metabolismo , SARS-CoV-2/genética , SARS-CoV-2/fisiologia , Humanos , Glicoproteína da Espícula de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , COVID-19/virologia , Antígeno 96 de Linfócito/metabolismo , Antígeno 96 de Linfócito/genética , Antígeno 96 de Linfócito/química , Simulação por Computador , Ligação Proteica
3.
Int J Mol Sci ; 24(7)2023 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-37047674

RESUMO

Toll-like receptors (TLRs) belong to a powerful system for the recognition and elimination of pathogen-associated molecular patterns (PAMPs) from bacteria, viruses, and other pathogens [...].


Assuntos
Receptores Toll-Like , Viroses , Humanos , Receptores Toll-Like/metabolismo , Transdução de Sinais , Inflamação , Bactérias/metabolismo , Imunidade Inata
4.
Int J Mol Sci ; 23(11)2022 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-35682644

RESUMO

The novel SARS-CoV-2 Omicron variant B.1.1.529, which emerged in late 2021, is currently active worldwide, replacing other variants, including the Delta variant, due to an enormously increased infectivity. Multiple substitutions and deletions in the N-terminal domain (NTD) and the receptor binding domain (RBD) in the spike protein collaborate with the observed increased infectivity and evasion from therapeutic monoclonal antibodies and vaccine-induced neutralizing antibodies after primary/secondary immunization. In contrast, although three mutations near the S1/S2 furin cleavage site were predicted to favor cleavage, observed cleavage efficacy is substantially lower than in the Delta variant and also lower compared to the wild-type virus correlating with significantly lower TMPRSS2-dependent replication in the lungs, and lower cellular syncytium formation. In contrast, the Omicron variant shows high TMPRSS2-independent replication in the upper airway organs, but lower pathogenicity in animal studies and clinics. Based on recent data, we present here a hypothesis proposing that the changed charge distribution in the Omicron's spike protein could lead to lower activation of Toll-like receptors (TLRs) in innate immune cells, resulting in lower NF-κB activation, furin expression, and viral replication in the lungs, and lower immune hyper-activation.


Assuntos
COVID-19 , SARS-CoV-2 , Animais , Furina/genética , Furina/metabolismo , NF-kappa B , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Receptores Toll-Like , Virulência
5.
Int J Mol Sci ; 22(19)2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34639132

RESUMO

Novel coronavirus SARS-CoV-2 has resulted in a global pandemic with worldwide 6-digit infection rates and thousands of death tolls daily. Enormous efforts are undertaken to achieve high coverage of immunization to reach herd immunity in order to stop the spread of SARS-CoV-2 infection. Several SARS-CoV-2 vaccines based on mRNA, viral vectors, or inactivated SARS-CoV-2 virus have been approved and are being applied worldwide. However, the recent increased numbers of normally very rare types of thromboses associated with thrombocytopenia have been reported, particularly in the context of the adenoviral vector vaccine ChAdOx1 nCoV-19 from Astra Zeneca. The statistical prevalence of these side effects seems to correlate with this particular vaccine type, i.e., adenoviral vector-based vaccines, but the exact molecular mechanisms are still not clear. The present review summarizes current data and hypotheses for molecular and cellular mechanisms into one integrated hypothesis indicating that coagulopathies, including thromboses, thrombocytopenia, and other related side effects, are correlated to an interplay of the two components in the vaccine, i.e., the spike antigen and the adenoviral vector, with the innate and immune systems, which under certain circumstances can imitate the picture of a limited COVID-19 pathological picture.


Assuntos
Vacinas contra COVID-19/efeitos adversos , COVID-19/prevenção & controle , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Trombocitopenia/etiologia , Trombose/etiologia , Adenoviridae/imunologia , Animais , COVID-19/imunologia , Vacinas contra COVID-19/imunologia , ChAdOx1 nCoV-19 , Vetores Genéticos/efeitos adversos , Vetores Genéticos/imunologia , Humanos , Púrpura Trombocitopênica Idiopática/etiologia , Púrpura Trombocitopênica Idiopática/imunologia , Glicoproteína da Espícula de Coronavírus/efeitos adversos , Trombocitopenia/imunologia , Trombose/imunologia , Vacinação/efeitos adversos
6.
Viruses ; 13(9)2021 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-34578468

RESUMO

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has expanded into a global pandemic, with more than 220 million affected persons and almost 4.6 million deaths by 8 September 2021. In particular, Europe and the Americas have been heavily affected by high infection and death rates. In contrast, much lower infection rates and mortality have been reported generally in Africa, particularly in the sub-Saharan region (with the exception of the Southern Africa region). There are different hypotheses for this African paradox, including less testing, the young age of the population, genetic disposition, and behavioral and epidemiological factors. In the present review, we address different immunological factors and their correlation with genetic factors, pre-existing immune status, and differences in cytokine induction patterns. We also focus on epidemiological factors, such as specific medication coverage, helminth distribution, and malaria endemics in the sub-Saharan region. An analysis combining different factors is presented that highlights the central role of the NF-κB signaling pathway in the African paradox. Importantly, insights into the interplay of different factors with the underlying immune pathological mechanisms for COVID-19 can provide a better understanding of the disease and the development of new targets for more efficient treatment strategies.


Assuntos
COVID-19/epidemiologia , COVID-19/virologia , Interações Hospedeiro-Patógeno , SARS-CoV-2/fisiologia , África/epidemiologia , Enzima de Conversão de Angiotensina 2/metabolismo , Biomarcadores , COVID-19/imunologia , COVID-19/metabolismo , Comorbidade , Citocinas/metabolismo , Suscetibilidade a Doenças , Geografia Médica , Saúde Global , Humanos , Mortalidade , NF-kappa B/metabolismo , Vigilância da População , Transdução de Sinais
7.
Front Immunol ; 11: 598444, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33362782

RESUMO

Patients infected with SARS-CoV-2 show a wide spectrum of clinical manifestations ranging from mild febrile illness and cough up to acute respiratory distress syndrome, multiple organ failure, and death. Data from patients with severe clinical manifestations compared to patients with mild symptoms indicate that highly dysregulated exuberant inflammatory responses correlate with severity of disease and lethality. Epithelial-immune cell interactions and elevated cytokine and chemokine levels, i.e. cytokine storm, seem to play a central role in severity and lethality in COVID-19. The present perspective places a central cellular pro-inflammatory signal pathway, NF-κB, in the context of recently published data for COVID-19 and provides a hypothesis for a therapeutic approach aiming at the simultaneous inhibition of whole cascades of pro-inflammatory cytokines and chemokines. The simultaneous inhibition of multiple cytokines/chemokines is expected to have much higher therapeutic potential as compared to single target approaches to prevent cascade (i.e. redundant, triggering, amplifying, and synergistic) effects of multiple induced cytokines and chemokines in critical stage COVID-19 patients.


Assuntos
Tratamento Farmacológico da COVID-19 , Síndrome da Liberação de Citocina/tratamento farmacológico , NF-kappa B/antagonistas & inibidores , Inibidores de Proteassoma/farmacologia , SARS-CoV-2/efeitos dos fármacos , Animais , COVID-19/imunologia , COVID-19/patologia , Síndrome da Liberação de Citocina/patologia , Citocinas/sangue , Modelos Animais de Doenças , Humanos , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Virus da Influenza A Subtipo H5N1/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/tratamento farmacológico , SARS-CoV-2/imunologia
8.
Front Chem ; 7: 575, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31475137

RESUMO

This work introduces a cost and time efficient procedure to specifically increase mesopore volume and specific surface area of biogenic silica (specific surface area: 147 m2 g-1 and mesopore volume: 0.23 cm3 g-1) to make it suitable for applications in adsorption or as catalyst support. The target values were a specific surface area of ~500 m2 g-1 and a mesopore volume of ~0.40-0.50 cm3 g-1 as these values are industrially relevant and are reached by potential concurring products such as precipitated silica, silica gel, and fumed silica. The applied process of partial pseudomorphic transformation was carried out as a single reaction step in a microwave reactor instead of commonly used convective heating. In addition, the conventionally used surfactant cetyltrimethylammonium bromide (CTABr) was substituted by the low-cost surfactant (Arquad® 16-29, cetyltrimethylammonium chloride (CTACl) aqueous solution). The influence of microwave heating, type of surfactant as well as the concentration of NaOH and CTACl on the textural and structural properties of the modified biogenic silica was investigated using nitrogen adsorption as well as scanning and transmission electron microscopy. The results show that the textural parameters of the modified biogenic silica can be exactly controlled by the amount of NaOH in the reaction solution. By variation of the NaOH concentration, specific surface areas in the range of 215-1,001 m2 g-1 and mesopore volumes of 0.25-0.56 cm3 g-1 were achieved after reaction at 393 K for 10 min. The presented microwave route using the low-cost surfactant solution decreases the reaction time by 99% and as shown in an example for German prices, lowers the costs for the surfactant by 76-99%.

9.
Biomater Sci ; 3(11): 1439-48, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26351701

RESUMO

Materials for delivery of oligonucleotides need to be simple to produce yet effective in vivo to be considered for clinical applications. Formulations of biomaterials based on combinations of existing demonstrated polymeric gene carriers with targeted derivatives are potential candidates for rapid translation but have not been fully explored for siRNA applications. Here we investigated formulations based on derivatised PEI for delivery of siRNA to gastrointestinal cancer cells. siRNA was complexed with linear PEI alone or with a mixture of linear PEI and transferrin-conjugated branched PEI (TfPEI), and knockdown of reporter genes was investigated. Overall, the in vitro use of complexes containing TfPEI resulted in up to 93% knockdown at 72 h post-transfection. Sustained knockdown was also achieved in a bioluminescent xenograft model. When complexes were delivered intratumorally, a 43% reduction in luminescence was achieved in the treated group compared with the control group 48 h after treatment. For systemic administration, only the intraperitoneal route, and not the intravenous route was effective, with 49% knockdown achieved at 72 h and sustained up to 144 h (44%) after a single administration of TfPEI-complexed siRNA. No toxicity or induction of the interferon response was observed. These findings demonstrate that simple formulations of transferrin-conjugated PEI with a 'parent' polymer such as linear PEI have potential as a method for therapeutic delivery of siRNA when administered either intratumorally or systemically.


Assuntos
Polietilenoimina/administração & dosagem , RNA Interferente Pequeno/química , Transferrina/administração & dosagem , Linhagem Celular Tumoral , Portadores de Fármacos , Inativação Gênica , Humanos , Polietilenoimina/química , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transferrina/química
10.
MAbs ; 4(4): 532-41, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22665069

RESUMO

A major limitation to the application of therapeutic monoclonal antibodies (mAbs) is their reduced in vivo efficacy compared with the high efficacy measured in vitro. Effector functions such as antibody-dependent cell-mediated cytotoxicity (ADCC) are dramatically reduced in vivo by the presence of high amounts of endogenous IgG in the serum. Recent studies have shown that modification of the glycosylation moieties attached to the Fc part of the mAb can enhance binding affinity to FcγRIIIα receptors on natural killer cells and thus may counteract the reduced in vivo efficacy. In the present study, a humanized IgG1/κ monoclonal antibody recognizing the tumor-associated carbohydrate antigen Lewis Y was stably produced in a moss expression system that allows glyco-engineering. The glyco-modified mAb (designated MB314) showed a highly homogeneous N-glycosylation pattern lacking core-fucose. A side-by-side comparison to its parental counterpart produced in conventional mammalian cell-culture (MB311, formerly known as IGN311) by fluorescence-activated cell sorting analysis confirmed that the target specificity of MB314 is similar to that of MB311. In contrast, ADCC effector function of MB314 was increased up to 40-fold whereas complement dependent cytotoxicity activity was decreased 5-fold. Notably, a release of immunostimulatory cytokines, including interferon γ, monocyte chemotactic protein-1 (MCP-1), interleukin-6 and tumor necrosis factor (TNF) was particularly induced with the glyco-modified antibody. TNF release was associated with CD14 (+) cells, indicating activation of monocytes.


Assuntos
Anticorpos Monoclonais Humanizados/imunologia , Citotoxicidade Celular Dependente de Anticorpos/imunologia , Citocinas/imunologia , Antígenos do Grupo Sanguíneo de Lewis/imunologia , Anticorpos Monoclonais Humanizados/metabolismo , Anticorpos Monoclonais Humanizados/farmacologia , Citotoxicidade Celular Dependente de Anticorpos/efeitos dos fármacos , Bryopsida/genética , Linhagem Celular Tumoral , Células Cultivadas , Quimiocina CCL2/imunologia , Quimiocina CCL2/metabolismo , Citocinas/metabolismo , Citometria de Fluxo , Glicosilação , Humanos , Imunoglobulina G/genética , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Interferon gama/imunologia , Interferon gama/metabolismo , Interleucina-6/imunologia , Interleucina-6/metabolismo , Células Matadoras Naturais/efeitos dos fármacos , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Ligação Proteica/imunologia , Engenharia de Proteínas/métodos , Receptores de IgG/imunologia , Receptores de IgG/metabolismo , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/metabolismo
11.
Antiviral Res ; 91(3): 304-13, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21777621

RESUMO

The appearance of highly pathogenic avian influenza A viruses of the H5N1 subtype being able to infect humans and the 2009 H1N1 pandemic reveals the urgent need for new and efficient countermeasures against these viruses. The long-term efficacy of current antivirals is often limited, because of the emergence of drug-resistant virus mutants. A growing understanding of the virus-host interaction raises the possibility to explore alternative targets involved in the viral replication. In the present study we show that the proteasome inhibitor VL-01 leads to reduction of influenza virus replication in human lung adenocarcinoma epithelial cells (A549) as demonstrated with three different influenza virus strains, A/Puerto Rico/8/34 (H1N1) (EC50 value of 1.7 µM), A/Regensburg/D6/09 (H1N1v) (EC50 value of 2.4 µM) and A/Mallard/Bavaria/1/2006 (H5N1) (EC50 value of 0.8 µM). In in vivo experiments we could demonstrate that VL-01-aerosol-treatment of BALB/c mice with 14.1 mg/kg results in no toxic side effects, reduced progeny virus titers in the lung (1.1 ± 0.3 log10 pfu) and enhanced survival of mice after infection with a 5-fold MLD50 of the human influenza A virus strain A/Puerto Rico/8/34 (H1N1) up to 50%. Furthermore, treatment of mice with VL-01 reduced the cytokine release of IL-α/ß, IL-6, MIP-1ß, RANTES and TNF-α induced by LPS or highly pathogen avian H5N1 influenza A virus. The present data demonstrates an antiviral effect of VL-01 in vitro and in vivo and the ability to reduce influenza virus induced cytokines and chemokines.


Assuntos
Citocinas/antagonistas & inibidores , Inibidores Enzimáticos/administração & dosagem , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Virus da Influenza A Subtipo H5N1/efeitos dos fármacos , Infecções por Orthomyxoviridae/tratamento farmacológico , Inibidores de Proteassoma , Replicação Viral/efeitos dos fármacos , Administração por Inalação , Animais , Antivirais/administração & dosagem , Antivirais/uso terapêutico , Linhagem Celular Tumoral , Citocinas/biossíntese , Farmacorresistência Viral , Inibidores Enzimáticos/uso terapêutico , Interações Hospedeiro-Patógeno , Humanos , Vírus da Influenza A Subtipo H1N1/crescimento & desenvolvimento , Virus da Influenza A Subtipo H5N1/crescimento & desenvolvimento , Influenza Humana/tratamento farmacológico , Influenza Humana/virologia , Lipopolissacarídeos/efeitos adversos , Lipopolissacarídeos/farmacologia , Pulmão/citologia , Pulmão/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/mortalidade , Infecções por Orthomyxoviridae/virologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Taxa de Sobrevida
12.
Pharmaceuticals (Basel) ; 3(6): 1887-1891, 2010 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-27713333

RESUMO

To complete the review article by Abes and colleagues (Pharmaceuticals 2010, 3, 146-157) which provides a good overview on recently developed approaches for generation of glyco-modified antibodies and the impact of glyco-modification of antibodies on their effector functions, important information should be added, namely that - besides the Glycart and the Biowa approach to generate de-fucosylated antibodies - innovative, moss derived methods have been shown to generate glyco-modified antibodies with improved effector function profile.

13.
Expert Opin Drug Discov ; 5(11): 1067-79, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22827745

RESUMO

IMPORTANCE OF THE FIELD: The unwanted immunogenicity of therapeutic proteins is a major concern regarding patient safety. Furthermore, pharmacokinetic, pharmacodynamic and clinical efficacy can be seriously affected by the immunogenicity of therapeutic proteins. Authorities have fully recognized this issue and demand appropriate and well-characterized assays to detect anti-drug antibodies (ADAs). AREAS COVERED IN THIS REVIEW: We provide an overview of the immunogenicity topic in general, the regulatory background and insight into underlying immunological mechanisms and the limited ability to predict clinical immunogenicity a priori. Furthermore, we comment on the analytical testing approach and the status-quo of appropriate method validation. WHAT THE READER WILL GAIN: The review provides insight regarding the analytical approach that is expected by regulatory authorities overseeing immunogenicity testing requirements. Additionally, the factors influencing immunogenicity are summarized and key references regarding immunogenicity testing approaches and method validation are discussed. TAKE HOME MESSAGE: The unwanted immunogenicity of protein therapeutics is of major concern because of its potential to affect patient safety and drug efficacy. Analytical testing is sophisticated and requires more than one assay. Because immunogenicity in humans is hardly predictable, assay development has to start in a timely fashion and for clinical studies immunogenicity assay validation is mandatory prior to analyzing patient serum samples. Regarding ADAs, the question remains as to when such antibodies are regarded of clinical relevance and what levels are, if at all, acceptable. In summary, the detection of ADAs should raise the awareness of the physician concerning patient safety and of the sponsor/manufacture concerning the immunogenic potential of the drug product.


Assuntos
Anticorpos/fisiologia , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Animais , Animais Geneticamente Modificados , Anticorpos/imunologia , Anticorpos Neutralizantes/imunologia , Apresentação de Antígeno/genética , Avaliação Pré-Clínica de Medicamentos , Humanos , Técnicas Imunológicas , Legislação de Medicamentos , Segurança do Paciente , Preparações Farmacêuticas/química , Estados Unidos , United States Food and Drug Administration
14.
Biomark Insights ; 3: 227-235, 2008 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-19578507

RESUMO

Serum parameters as indicators for the efficacy of therapeutic drugs are currently in the focus of intensive research. The induction of certain cytokines (or cytokine patterns) is known to be related to the status of the immune response e.g. in regulating the T(H)1/T(H)2 balance. Regarding their potential value as surrogate parameters in clinical trials and subsequently for the assignment of treatment efficacy, the accurate and reliable determination of cytokines in patient serum is mandatory. Because serum samples are precious and limited, test methods-like the xMAP multiplex technology-that allow for the simultaneous determination of a variety of cytokines from only a small sample aliquot, can offer great advantages.We here have compared multiplex kits from three different manufactures and found striking differences upon standardizing using WHO standards for selected cytokines. We therefore extended our xMAP multiplex measurements investigations to an ex-vivo situation by testing serum samples and found that the cytokine amounts measured was critically influenced by the actual kit used. The presented data indicate that statements regarding the quantitive determination of cytokines-and therefore their use as biomarkers-in serum samples have to be interpreted with caution.

15.
J Chromatogr B Analyt Technol Biomed Life Sci ; 852(1-2): 250-6, 2007 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-17296336

RESUMO

During the analytical characterization of the humanized Lewis-Y specific monoclonal antibody IGN311 (IgG1/kappa) used for passive anti-cancer therapy in humans, isoelectric focusing (IEF) experiments revealed that IGN311 batches produced in serum-containing and serum-free medium, respectively, displayed different banding patterns. The additional bands in the IEF pattern correlated with additional peaks observed by subsequent cation exchange (CEX)-HPLC analysis. Since the IEF pattern is one of the specification criteria in the quality control of monoclonal antibodies and a non-matching pattern may be indicative for lot-to-lot inconsistency, this phenomenon was investigated in detail. First, we investigated whether a difference in antibody glycosylation was the cause for the observed charge heterogeneity. De-N-glycosylation experiments demonstrated that charge heterogeneity observed in the IEF pattern is not a consequence of glycosylation. In contrast, sample treatment by carboxypeptidase B, removing the carboxy-terminal lysine residues from the two heavy chains of the antibody, resulted in reduced charge heterogeneity eliminating the two most basic bands observed in IEF. These data were supported by reversed phase HPLC-MALDI-TOF-MS analysis of enzymatically cleaved peptides of the antibody as well as by carboxy-terminal sequencing of the heavy chains. It was demonstrated that the differences in the IEF banding pattern were due to lysine clipping occurring during the production of the antibody. The antibody batch produced under serum-free conditions was less affected by lysine clipping. Both antibody variants--clipped and unclipped--elicited the same potency in a complement dependent cytotoxicity (CDC) assay demonstrating that lysine clipping of IGN311 does not impair Fc-mediated effector functions.


Assuntos
Imunoglobulina G/análise , Antígenos do Grupo Sanguíneo de Lewis/imunologia , Lisina/química , Receptores Fc/fisiologia , Sequência de Aminoácidos , Cromatografia de Afinidade , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Eletroforese em Gel Bidimensional , Glicosilação , Humanos , Imunoglobulina G/química , Imunoglobulina G/imunologia , Dados de Sequência Molecular , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
16.
Mol Immunol ; 44(7): 1815-7, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17011625

RESUMO

A major limitation to the application of therapeutic IgG antibodies (Abs) is their reduced in vivo efficacy compared to their high efficacy as measured in vitro. Recently, Preithner et al. showed that the high amount of endogenous serum IgG impairs the antibody-dependent cellular cytotoxicity effector function (ADCC) of therapeutic Abs in vivo by competing for binding to Fcgamma-RIII on the effector cells. Modification of the glycosylation moieties attached to the Fc part of the Ab, e.g. de-fucosylation, has been shown to increase ADCC activity. We here show that the ADCC activity of a fucose-deficient, moss-produced therapeutic IgG is not impaired by normal human serum. The increased ADCC activity of the fucose-deficient Ab variant even in the presence of high endogenous IgG indicates that glyco-engineering of Abs may translate into improved clinical efficacy. Noteworthy, moss production of glyco-modified Abs should be applicable to a broad variety of therapeutic Abs currently in use indicative for the potential of this technology platform.


Assuntos
Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Citotoxicidade Celular Dependente de Anticorpos/imunologia , Imunoglobulina G/imunologia , Engenharia de Proteínas , Anticorpos Monoclonais/uso terapêutico , Ligação Competitiva , Linhagem Celular Tumoral , Glicosilação , Humanos , Conformação Proteica , Receptores de IgG/imunologia
17.
Cancer Immunol Immunother ; 56(6): 863-73, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17009044

RESUMO

Tumor-associated antigens resulting from aberrant glycosylation, such as the SialylTn carbohydrate antigen, are frequently over-expressed on cancer cells and provide potential targets for cancer vaccination. Immunization of Rhesus monkeys with SialylTn coupled to a highly immunogenic carrier molecule and formulated on aluminum hydroxide induced a strong immune response against the carrier protein but only a moderate IgM immune response against the SialylTn carbohydrate antigen. Co-formulation with QS-21 adjuvant dramatically enhanced the anti-SialylTn immune response and resulted in a SialylTn-specific IgG switch. The kinetics of the carbohydrate-specific IgG response correlated with a temporary release of cytokines such as IFNgamma, IL-2, IL-1beta, TNFalpha and GM-CSF which was measurable in the immune serum by xMAP Multiplex technology. Furthermore, tumor cell killing by activated natural killer cells was induced. These data demonstrate that immunization with a tumor-associated carbohydrate antigen in a highly immunogenic formulation results in a temporary release of type 1 cytokines which may be required for the induction of a specific IgG immune response against the carbohydrate antigen as well as for activation of effector cells against tumor cells.


Assuntos
Adjuvantes Imunológicos , Antígenos Glicosídicos Associados a Tumores/imunologia , Vacinas Anticâncer/imunologia , Citocinas/sangue , Células Matadoras Naturais/imunologia , Saponinas/imunologia , Animais , Anticorpos Monoclonais/imunologia , Citocinas/metabolismo , Citotoxicidade Imunológica , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Ativação Linfocitária/imunologia , Macaca mulatta , Vacinas Conjugadas/imunologia
18.
J Pharmacol Exp Ther ; 319(3): 1459-66, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16963623

RESUMO

The blood group-related Lewis Y antigen is expressed on the majority of human cancers of epithelial origin with only limited expression on normal tissue. Therefore, the Lewis Y antigen represents an interesting candidate for antibody-based treatment strategies. Previous experiments showed that the humanized Lewis Y-specific monoclonal antibody, IGN311, reduced ErbB-receptor-mediated stimulation of mitogen-activated protein kinase by altering receptor recycling. Here, we tested whether binding of IGN311 to growth factor receptors is relevant also to inhibition of tumor growth in vivo. Prolonged incubation with IGN311 of human tumor cell lines, which express high levels of ErbB1 (A431) or ErbB2 (SK-BR-3), resulted in down-regulation of the receptors and inhibition of cell proliferation. IGN311 inhibited the growth of tumors derived from A431 cells xenografted in nude mice. Treatment with IGN311 was associated with a down-regulation of ErbB1 in the excised tumor tissue. Importantly, these effects of IGN311 were also mimicked by the Fab fragment of IGN311. These data indicate that tumor cell growth inhibition by IGN311 cannot solely be accounted for by invoking cellular and humoral immunological mechanisms. A direct effect on signaling via binding to Lewis Y glycosylated growth factor receptors on tumor cells is also likely to contribute to the therapeutic effect of IGN311 in vivo.


Assuntos
Anticorpos Bloqueadores/farmacologia , Genes erbB-1/efeitos dos fármacos , Antígenos do Grupo Sanguíneo de Lewis/imunologia , Animais , Anticorpos Bloqueadores/imunologia , Células Cultivadas , Regulação para Baixo/efeitos dos fármacos , Feminino , Fragmentos Fab das Imunoglobulinas/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Transplante de Neoplasias , Transdução de Sinais/efeitos dos fármacos , Transplante Heterólogo
19.
Biotechnol J ; 1(2): 138-47, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16892244

RESUMO

Cancer is the second leading cause of death in the industrialized world. Most cancer patients are treated by a combination of surgery, radiation and/or chemotherapy. Whereas the primary tumor can, in most cases, be efficiently treated by a combination of these standard therapies, preventing the metastatic spread of the disease through disseminated tumor cells is often not effective. The eradication of disseminated tumor cells present in the blood circulation and micro-metastases in distant organs therefore represents another promising approach in cancer immunotherapy. Main strategies of cancer immunotherapy aim at exploiting the therapeutic potential of tumor-specific antibodies and cellular immune effector mechanisms. Whereas passive antibody therapy relies on the repeated application of large quantities of tumor antigen-specific antibodies, active immunotherapy aims at the generation of a tumor-specific immune response combining both humoral and cytotoxic T cell effector mechanisms by the host's immune system following vaccination. In the first part of this review, concurrent developments in active and passive cancer immunotherapy are discussed. In the second part, the various approaches for the production of optimized monoclonal antibodies used for anti-cancer vaccination are summarized.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Vacinas Anticâncer/uso terapêutico , Citocinas/uso terapêutico , Imunoterapia/métodos , Imunoterapia/tendências , Neoplasias/imunologia , Neoplasias/terapia , Animais , Antineoplásicos/uso terapêutico , Humanos
20.
Vaccine ; 24(13): 2349-57, 2006 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-16406172

RESUMO

Tumor-associated antigens resulting from aberrant glycosylation, such as the SialylTn carbohydrate antigen, are over-expressed on cancer cells and provide potential targets for cancer vaccination. However, as T-cell-independent antigens carbohydrates are poorly immunogenic, and fail to induce memory. In order to increase the immunogenicity we have coupled the SialylTn carbohydrate antigen to a highly immunogenic carrier molecule, the murine monoclonal antibody mAb17-1A. An immunogenic formulation of the SialylTn-mAb17-1A conjugate on alhydrogel, IGN402, with or without additional adjuvants was tested in Rhesus monkeys for tolerability and immunogenicity. A significant antibody response against mAb17-1A antibody was found. Importantly, also a specific immune response against SialylTn carbohydrate and binding to tumor cells was induced. Immunization in the presence of additional adjuvants, such as QS-21, strongly enhanced the immune response against the carbohydrate antigen, and resulted in induction of SialylTn-specific IgG antibodies. Noteworthy, also an induced temporary release of cytokines including IFNgamma and IL-2, indicative for T-cell activation, was measured. The data indicate that carrier-induced T-cell help together with strong adjuvant is sufficient for carbohydrate specific class switch induction.


Assuntos
Anticorpos Monoclonais/imunologia , Antígenos Glicosídicos Associados a Tumores/imunologia , Vacinas Anticâncer/imunologia , Imunoglobulina G/biossíntese , Animais , Citocinas/biossíntese , Imunização , Ativação Linfocitária , Macaca mulatta , Coelhos , Saponinas/administração & dosagem , Linfócitos T/imunologia , Vacinas Conjugadas/imunologia
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