Bivalent monoclonal IgY antibody formats by conversion of recombinant antibody fragments

Monoclonal IgY antibodies: advancements and limitations for immunodiagnosis and immunotherapy applications

Due to their high specificity and scalability, Monoclonal IgY antibodies have emerged as a valuable alternative to traditional polyclonal IgY antibodies. This abstract provides an overview of the production and purification methods of monoclonal IgY antibodies, highlights their advantages over polyclonal IgY antibodies, and discusses their recent applications. Monoclonal recombinant IgY antibodies, in contrast to polyclonal IgY antibodies, offer several benefits. such as derived from a single B-cell clone, monoclonal antibodies exhibit superior specificity, ensuring consistent and reliable results. Furthermore, it explores the suitability of monoclonal IgY antibodies for low- and middle-income countries, considering their cost-effectiveness and accessibility. We also discussed future directions and challenges in using polyclonal IgY and monoclonal IgY antibodies. In conclusion, monoclonal IgY antibodies offer substantial advantages over polyclonal IgY antibodies regarding specificity, scalability, and consistent performance. Their recent applications in diagnostics, therapeutics, and research highlight their versatility.

The antigenicity and cholesteroid nature of mycolic acids determined by recombinant chicken antibodies

Mycolic acids (MA) are major, species-specific lipid components of Mycobacteria and related genera. In Mycobacterium tuberculosis, it is made up of alpha-, methoxy- and keto-MA, each with specific biological functions and conformational characteristics. Antibodies in tuberculosis (TB) patient sera respond differently towards the three MA classes and were reported to cross-react with cholesterol. To understand the antigenicity and cholesterol cross-reactivity of MA, we generated three different chicken -derived phage-displayed single-chain variable fragments (scFv) that reacted similarly towards the natural mixture of MA, but the first recognized all three classes of chemically synthetic MAs, the second only the two oxygenated types of MAs and the third only methoxy MA. The cholesterol cross-reactivity was investigated after grafting each of the three scFv types onto two configurations of constant chain domains–CH1-4 and CH2-4. Weak but significant cross-reactivity with cholesterol was found only with CH2-4 versions, notably those two that were also able to recognize the trans-keto MA. The cholesteroid nature of mycobacterial mycolic acids therefore seems to be determined by the trans-keto MA subclass. The significantly weaker binding to cholesterol in comparison to MA confirms the potential TB diagnostic application of these antibodies.

Insights into the chicken IgY with emphasis on the generation and applications of chicken recombinant monoclonal antibodies

The advantages of chicken (Gallus gallus domesticus) antibodies as immunodiagnostic and immunotherapeutic biomolecules has only been recently recognized. Even so, chicken antibodies remain less-well characterized than their mammalian counterparts. This review aims at providing a current overview of the structure, function, development and generation of chicken antibodies. Additionally, brief but comprehensive insights into current knowledge pertaining to the immunogenetic framework and diversity-generation of the chicken immunoglobulin repertoire which have contributed to the establishment of recombinant chicken mAb-generating methods are discussed. Focus is provided on the current methods used to generate antibodies from chickens with added emphasis on the generation of recombinant chicken mAbs and its derivative formats. The advantages and limitations of established protocols for the generation of chicken mAbs are highlighted. The various applications of recombinant chicken mAbs and its derivative formats in immunodiagnostics and immunotherapy are further detailed.

Avian IgY antibodies and their recombinant equivalents in research, diagnostics and therapy

The generation and use of avian antibodies is of increasing interest in a wide variety of applications within the life sciences. Due to their phylogenetic distance, mechanisms of immune diversification and the way in which they deposit IgY immunoglobulin in the egg yolk, chickens provide a number of advantages compared to mammals as hosts for immunization. These advantages include: the one-step purification of antibodies from egg yolk in large amounts facilitates having a virtually continuous supply; the epitope spectrum of avian antibodies potentially grants access to novel specificities; the broad absence of cross-reactivity with mammalian epitopes avoids assay interference and improves the performance of immunological techniques. The polyclonal nature of IgY antibodies has limited their use since avian hybridoma techniques are not well established. Recombinant IgY, however, can be generated from mammalian monoclonal antibodies which makes it possible to further exploit the advantageous properties of the IgY scaffold. Moreover, cloning and selecting the immune repertoire from avian organisms is highly efficient, yielding antigen-specific antibody fragments. The recombinant approach is well suited to circumvent any limitations of polyclonal antibodies. This review presents comprehensive information on the generation, purification, modification and applications of polyclonal and monoclonal IgY antibodies.

Close-up of the immunogenic α1,3-galactose epitope as defined by a monoclonal chimeric immunoglobulin E and human serum using saturation transfer difference (STD) NMR

Anaphylaxis mediated by carbohydrate structures is a controversially discussed phenomenon. Nevertheless, IgE with specificity for the xenotransplantation antigen α1,3-Gal (α-Gal) are associated with a delayed type of anaphylaxis, providing evidence for the clinical relevance of carbohydrate epitopes in allergy. The aim of this study was to dissect immunoreactivity, interaction, and fine epitope of α-Gal-specific antibodies to obtain insights into the recognition of carbohydrate epitopes by IgE antibodies and their consequences on a molecular and cellular level. The antigen binding moiety of an α-Gal-specific murine IgM antibody was employed to construct chimeric IgE and IgG antibodies. Reactivity and specificity of the resulting antibodies were assessed by means of ELISA and receptor binding studies. Using defined carbohydrates, interaction of the IgE and human serum was assessed by mediator release assays, surface plasmon resonance (SPR), and saturation transfer difference NMR analyses. The α-Gal-specific chimeric IgE and IgG antibodies were proven functional regarding interaction with antigen and Fc receptors. SPR measurements demonstrated affinities in the micromolar range. In contrast to a reference antibody, anti-Gal IgE did not induce mediator release, potentially reflecting the delayed type of anaphylaxis. The α1,3-Gal epitope fine structures of both the recombinant IgE and affinity-purified serum were defined by saturation transfer difference NMR, revealing similar contributions of carbohydrate residues and participation of both galactose residues in interaction. The antibodies generated here constitute the principle underlying α1,3-Gal-mediated anaphylaxis. The complementary data of affinity and fine specificity may help to elucidate the recognition of carbohydrates by the adaptive immune response and the molecular requirements of carbohydrate-based anaphylaxis.

Generation and epitope analysis of human monoclonal antibody isotypes with specificity for the Timothy grass major allergen Phl p 5a

The scarcity of monoclonal human IgE antibodies with specificity for defined allergens is a bottleneck for the molecular characterisation of allergens and their epitopes. Insights into the characteristics of such antibodies may allow for analyses of the molecular basis underlying allergenicity and cross-reactivity, standardisation of allergens as well as improvement of allergy diagnostics and therapeutics. Here we report the generation and application of the first set of authentic human IgG, IgE and IgA antibodies. On the basis of a Phl p 5a specific antibody fragment, a lambda light chain and the IgG1, IgG4, IgE, IgA1, and IgA2 heavy chains, the corresponding human immunoglobulins were constructed and produced in mammalian cells. In parallel, a murine hybridoma line with specificity for Phl p 5a was established, recloned and produced as human chimeric IgE. After purification, immunoreactivity of the antibodies with the allergen was assessed. Applicability in allergy diagnostics was confirmed by establishment of artificial human sera. Functionality of both antibodies was further demonstrated in receptor binding studies and mediator release assays using humanised rat basophil leukaemia cells (RBL-SX38) suggesting the presence of spatially separate epitopes. By using Phl p 5 fusion proteins and recombinant IgE in immunoblotting and mediator release assays we assigned the epitope of the authentic IgE to a looped stretch exclusively present in Phl p 5a. In summary, the Phl p 5-specific antibodies are the first full set of allergy-related antibody isotypes of their kind and represent valuable tools for studies of fundamental mechanisms and structure/function relationships in allergy.

Quantitation of serum IgE by using chimeras of human IgE receptor and avian immunoglobulin domains

Anti-IgE therapeutics represent an efficient approach in the management of IgE-mediated allergic asthma. However, monitoring the reduction of IgE levels into a therapeutically efficient range requires the determination of residual serum IgE. We established an analytical approach to distinguish free and anti-IgE complexed serum IgE based on soluble derivatives of the human high-affinity IgE receptor. Soluble receptor derivatives represent an ideal means to analyze receptor antagonism by any ligand or blocking antibody. Therefore, the FcεRI ectodomain was fused with avian IgY constant domains that circumvent susceptibility to interference phenomena and improve assay performance. After production in HEK293 cells, subsequent characterization by enzyme-linked immunosorbent assay and immunoblotting confirmed the suitability of avian IgY constant domains for immobilization and detection purposes. To provide further insights into the different IgE reactivities, free allergen-specific IgE was also determined. Monitoring of sera from omalizumab-treated patients during the course of therapy revealed the applicability for assessment of omalizumab-complexed versus noncomplexed serum IgE. These parameters may allow correlation to clinical responses during anti-IgE therapy with the perspective of biomonitoring.

Development of DNA-designed avian IgY antibodies for quantitative determination of bovine interferon-gamma

Interferon-gamma (IFN-γ), a cytokine produced by sensitized T lymphocytes, is one of the key elements in defining T helper 1 lymphocyte immune responses. Quantitative evaluation of IFN-γ expression could provide an important analytical tool for measurement of cell-mediated immunity and investigating immune responses to infectious diseases. Method of DNA-designed avian IgY antibodies was used for production of monospecific polyclonal antibodies that allows quantification of the recombinant bovine IFN-γ protein. IFN-γ cDNA was subcloned and expressed in mammalian expression plasmid (pcDNA3.1(+)) under the control of the human cytomegalovirus promoter. Chickens were immunized by plasmid DNA, and egg yolk antibodies extracted from eggs were collected after immunization. IgY-specific antibodies were evaluated by an antigen capture enzyme-linked immunosorbent assay (ELISA) using recombinant IFN-γ. Based on the results, developed bovine IFN-γ capture ELISA could detect up to 1 ng/ml of IFN-γ by 64-fold diluted IgY. Monospecific anti-bovine IFN-γ antibodies generated in chickens are useful for quantifying different concentrations of recombinant bovine IFN-γ, which is expressed in cell culture.