Aggregated Recombinant Human Interferon Beta Induces Antibodies but No Memory in Immune-Tolerant Transgenic Mice

Purpose To study the influence of protein aggregation on the immunogenicity of recombinant human interferon beta (rhIFNβ) in wild-type mice and transgenic, immune-tolerant mice, and to evaluate the induction of immunological memory. Methods RhIFNβ-1b and three rhIFNβ-1a preparations with different aggregate levels were injected intraperitoneally in mice 15 × during 3 weeks, and the mice were rechallenged with rhIFNβ-1a. The formation of binding (BABs) and neutralizing antibodies (NABs) was monitored. Results Bulk rhIFNβ-1a contained large, mainly non-covalent aggregates and stressed rhIFNβ-1a mainly covalent, homogeneous (ca. 100 nm) aggregates. Reformulated rhIFNβ-1a was essentially aggregate-free. All products induced BABs and NABs in wild-type mice. Immunogenicity in the transgenic mice was product dependent. RhIFNβ-1b showed the highest and reformulated rhIFNβ-1a the lowest immunogenicity. In contrast with wild-type mice, transgenic mice did not show NABs, nor did they respond to the rechallenge

Oxidized and Aggregated Recombinant Human Interferon Beta is Immunogenic in Human Interferon Beta Transgenic Mice

PurposeTo study the effect of oxidation on the structure of recombinant human interferon beta-1a (rhIFNβ-1a) and its immunogenicity in wild-type and immune-tolerant transgenic mice.MethodsUntreated rhIFNβ-1a was degraded by metal-catalyzed oxidation, H2O2-mediated oxidation, and guanidine-mediated unfolding/refolding. Four rhIFNβ-1a preparations with different levels of oxidation and aggregation were injected intraperitoneally in mice 15× during 3 weeks. Both binding and neutralizing antibodies were measured.ResultsAll rhIFNβ-1a preparations contained substantial amounts of aggregates. Metal-catalyzed oxidized rhIFNβ-1a contained high levels of covalent aggregates as compared with untreated rhIFNβ-1a. H2O2-treated rhIFNβ-1a showed an increase in oligomer and unrecovered protein content by HP-SEC; RP-HPLC revealed protein oxidation. Guanidine-treated rhIFNβ-1a mostly consisted of dimers and oligomers and some non-covalent aggregates smaller in size than those in untreated rhIFNβ-1a. All degraded samples showed alterations in tertiary protein structure. Wild-type mice showed equally high antibody responses against all preparations. Transgenic mice were discriminative, showing elevated antibody responses against both metal-catalyzed oxidized and H2O2-treated rhIFNβ-1a as compared to untreated and guanidine-treated rhIFNβ-1a.ConclusionsOxidation-mediated aggregation increased the immunogenicity of rhIFNβ-1a in transgenic mice, whereas aggregated preparations devoid of measurable oxidation levels were hardly immunogenic

Development of ADA Against Recombinant Human Interferon Beta in Immune Tolerant Mice Requires Rapid Recruitment of CD4(+) T Cells, Induces Formation of Germinal Centers but Lacks Susceptibility for (Most) Adjuvants

Immunological processes leading to formation of antidrug antibodies (Abs) against recombinant human proteins remain poorly understood. Animal and clinical studies revealed that immunogenicity shares both T-cell-dependent (requirement of CD4(+) T cells, isotype switching) and T-cell-independent (involvement of Marginal Zone B cells, apparent lack of memory) characteristics. We used immune tolerant mice to study the mechanism underlying immunogenicity in more detail. We found that CD4(+) T cells were crucial at early stages of Ab responses against rhIFNβ. In addition, we found a similar number of germinal centers (GCs) in spleen after rhIFNβ treatment as after treatment with a foreign protein. However, neither Ab titers nor the number of GCs was increased by adsorption of rhIFNβ on aluminum hydroxide. Therefore, we tested the effect of several immune adjuvants in a follow-up study. We found that only conjugation of rhIFNβ to a carrier protein (cholera toxin subunit B) was effective in boosting Ab titers. However, these conjugates failed to trigger rhIFNβ specific memory formation. Our findings show that early events of the immunogenicity reaction to self-proteins are CD4(+) T-cell dependent. Nevertheless, despite those similarities, immunogenicity of human proteins is clearly not a classical CD4(+) T-cell-dependent response. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:396-406, 2015

Development of a transgenic mouse model to study the immunogenicity of recombinant human insulin

Mouse models are commonly used to assess the immunogenicity of therapeutic proteins and to investigate the immunological processes leading to antidrug antibodies. The aim of this work was to develop a transgenic (TG) Balb/c mouse model for evaluating the immunogenicity of recombinant human insulin (insulin) formulations. Validation of the model was performed by measuring the antibody response against plain and particulate insulin in TG and nontransgenic (NTG) mice. Intraperitoneal administration of insulin (20 μg/dose, 12 doses over a period of 4 weeks) did not break the immune tolerance of the TG mice, whereas it did elicit antibodies in NTG mice. The immune tolerance of TG mice could be circumvented, albeit at low titers, by administering insulin covalently bound to 50-nm polystyrene nanoparticles. The TG mouse model was employed to compare the immunogenicity of oxidized aggregated insulin, oxidized nonaggregated insulin, and three commercially available formulations of insulin variants (i.e., Levemir®, Insulatard®, and Actrapid®). Oxidized insulin, aggregated or nonaggregated, was moderately immunogenic in TG mice (50% and 33% responders, respectively), whereas the immunogenicity of the commercial formulations was low. This model can be used to compare the immunogenicity of insulin formulations and to study immune mechanisms of antibody formation against insulin

Development of ADA Against Recombinant Human Interferon Beta in Immune Tolerant Mice Requires Rapid Recruitment of CD4(+) T Cells, Induces Formation of Germinal Centers but Lacks Susceptibility for (Most) Adjuvants

Immunological processes leading to formation of antidrug antibodies (Abs) against recombinant human proteins remain poorly understood. Animal and clinical studies revealed that immunogenicity shares both T-cell-dependent (requirement of CD4(+) T cells, isotype switching) and T-cell-independent (involvement of Marginal Zone B cells, apparent lack of memory) characteristics. We used immune tolerant mice to study the mechanism underlying immunogenicity in more detail. We found that CD4(+) T cells were crucial at early stages of Ab responses against rhIFNβ. In addition, we found a similar number of germinal centers (GCs) in spleen after rhIFNβ treatment as after treatment with a foreign protein. However, neither Ab titers nor the number of GCs was increased by adsorption of rhIFNβ on aluminum hydroxide. Therefore, we tested the effect of several immune adjuvants in a follow-up study. We found that only conjugation of rhIFNβ to a carrier protein (cholera toxin subunit B) was effective in boosting Ab titers. However, these conjugates failed to trigger rhIFNβ specific memory formation. Our findings show that early events of the immunogenicity reaction to self-proteins are CD4(+) T-cell dependent. Nevertheless, despite those similarities, immunogenicity of human proteins is clearly not a classical CD4(+) T-cell-dependent response. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:396-406, 2015

Natural Antibodies Against Bone Morphogenic Proteins and Interferons in Healthy Donors and in Patients with Infections Linked to Type-1 Cytokine Responses

In patients receiving recombinant therapeutic proteins, the production of antibodies against the therapeutics is a rising problem. The antibodies can neutralize and interfere with the efficacy and safety of drugs and even cause severe side effects if they cross-react against the natural, endogenous protein. Various factors have been identified to influence the immunogenic potential of recombinant human therapeutics, including several patients' characteristics. In recent years, so-called naturally occurring antibodies against cytokines and growth factors have been detected in naive patients before start of treatment with recombinant human therapeutics. The role of naturally occurring antibodies is not well understood and their influence on production of anti-drug antibodies is not known. One might speculate that the presence of naturally occurring antibodies increases the likelihood of eliciting anti-drug antibodies once treatment with the corresponding recombinant therapeutic protein is started. We screened serum samples from 410 healthy controls and patients for auto-antibodies against bone morphogenetic proteins (BMPs) 2 and 7 and interferon (IFN)-alpha, -beta, and -gamma in a new 3-step approach: rough initial screening, followed by competition and protein A/G depletion. Naturally occurring antibodies against these proteins were detected in 2% to 4% of the tested sera. Individuals who are 65 years or older had a slightly higher occurrence of naturally occurring antibodies. Auto-antibodies against BMP-7 and IFN-alpha were mainly comprised of IgM isotypes, and natural antibodies against BMP-2, IFN-beta, and -gamma were mainly IgG. To ensure assay specificity, assays were also used to detect antibodies against BMP-7 in patients being treated with rhBMP-7 before and after surgical procedure. Fifty percent of the treated patients had persistent anti-BMP-7 antibodies over time. The 3-step approach provides an attractive tool to identify naturally occurring antibodies in naive patients.Immunogenetics and cellular immunology of bacterial infectious disease