The MHC Associated Peptide Proteomics assay is a useful tool for the non-clinical assessment of immunogenicity.

The propensity of therapeutic proteins to elicit an immune response, poses a significant challenge in clinical development and safety of the patients. Assessment of immunogenicity is crucial to predict potential adverse events and design safer biologics. In this study, we employed MHC Associated Peptide Proteomics (MAPPS) to comprehensively evaluate the immunogenic potential of re-engineered variants of immunogenic FVIIa analog (Vatreptacog Alfa). Our finding revealed the correlation between the protein sequence affinity for MHCII and the number of peptides identified in a MAPPS assay and this further correlates with the reduced T-cell responses. Moreover, MAPPS enable the identification of "relevant" T cell epitopes and may contribute to the development of biologics with lower immunogenic potential.

Impact of Stress on the Immunogenic Potential of Adalimumab.

Monoclonal antibodies against tumor necrosis factor-alpha (TNFα) are widely used for treatment of inflammatory diseases. However, despite the inhibitory effect this class of drugs has on the immune system, anti-drug antibodies are often formed with continuous use. Particles formed during stress conditions, which can be used to simulate storage and handling conditions of commercial antibodies, have previously been associated with the formation of anti-drug antibodies. This study investigates the relationship between particles, oligomerization, folding and chemical degradation on the in vitro cytokine response toward the TNFα inhibitor adalimumab. Adalimumab aggregates generated using stir and heat stress were fractionated into distinct sub-populations, and their structure and immunogenic potential were evaluated. A chemically degraded sample of adalimumab was included to compare particle composition with the milder accelerated heat and stir stressed conditions. Particles from stressed adalimumab samples induced elevated cytokine levels and CD4+ T cell proliferation in vitro compared to non-stressed samples. Samples enriched with both submicron and subvisible particles of adalimumab induced the strongest cytokine release and the strongest CD4+ T cell proliferation despite maintaining some TNFα inhibitory functionality. Samples that were stressed and subsequently purified of subvisible and submicron particles did not elicit a significantly higher cytokine response or show increased CD4+ T cell proliferation compared to a non-stressed sample. Oxidation-induced chemical modifications in adalimumab, mainly in Met, His, Trp, and Tyr, were not found to be sufficient in absence of particle formation to induce increased CD4+ T cell proliferation or cytokine release despite less decreased TNFα inhibitory activity of adalimumab. These observations provide further evidence that particles do indeed potentiate the immunogenic potential of adalimumab.

Assay format diversity in pre-clinical immunogenicity risk assessment: Toward a possible harmonization of antigenicity assays.

A major impediment to successful use of therapeutic protein drugs is their ability to induce anti-drug antibodies (ADA) that can alter treatment efficacy and safety in a significant number of patients. To this aim, in silico, in vitro, and in vivo tools have been developed to assess sequence and other liabilities contributing to ADA development at different stages of the immune response. However, variability exists between similar assays developed by different investigators due to the complexity of assays, a degree of uncertainty about the underlying science, and their intended use. The impact of protocol variations on the outcome of the assays, i.e., on the immunogenicity risk assigned to a given drug candidate, cannot always be precisely assessed. Here, the Non-Clinical Immunogenicity Risk Assessment working group of the European Immunogenicity Platform (EIP) reviews currently used assays and protocols and discusses feasibility and next steps toward harmonization and standardization.

Mitigation of T-cell dependent immunogenicity by reengineering factor VIIa analogue.

Vatreptacog alfa (VA), a recombinant activated human factor VII (rFVIIa) variant with 3 amino acid substitutions, was developed to provide increased procoagulant activity in hemophilia patients with inhibitors to factor VIII or factor IX. In phase 3 clinical trials, changes introduced during the bioengineering of VA resulted in the development of undesired anti-drug antibodies in some patients, leading to the termination of a potentially promising therapeutic protein product. Here, we use preclinical biomarkers associated with clinical immunogenicity to validate our deimmunization strategy applied to this bioengineered rFVIIa analog. The reengineered rFVIIa analog variants retained increased intrinsic thrombin generation activity but did not elicit T-cell responses in peripheral blood mononuclear cells isolated from 50 HLA typed subjects representing the human population. Our algorithm, rational immunogenicity determination, offers a broadly applicable deimmunizing strategy for bioengineered proteins.

Development of an objective gene expression panel as an alternative to self-reported symptom scores in human influenza challenge trials.

BACKGROUND: Influenza challenge trials are important for vaccine efficacy testing. Currently, disease severity is determined by self-reported scores to a list of symptoms which can be highly subjective. A more objective measure would allow for improved data analysis. METHODS: Twenty-one volunteers participated in an influenza challenge trial. We calculated the daily sum of scores (DSS) for a list of 16 influenza symptoms. Whole blood collected at baseline and 24, 48, 72 and 96 h post challenge was profiled on Illumina HT12v4 microarrays. Changes in gene expression most strongly correlated with DSS were selected to train a Random Forest model and tested on two independent test sets consisting of 41 individuals profiled on a different microarray platform and 33 volunteers assayed by qRT-PCR. RESULTS: 1456 probes are significantly associated with DSS at 1% false discovery rate. We selected 19 genes with the largest fold change to train a random forest model. We observed good concordance between predicted and actual scores in the first test set (r = 0.57; RMSE = -16.1%) with the greatest agreement achieved on samples collected approximately 72 h post challenge. Therefore, we assayed samples collected at baseline and 72 h post challenge in the second test set by qRT-PCR and observed good concordance (r = 0.81; RMSE = -36.1%). CONCLUSIONS: We developed a 19-gene qRT-PCR panel to predict DSS, validated on two independent datasets. A transcriptomics based panel could provide a more objective measure of symptom scoring in future influenza challenge studies. Trial registration Samples were obtained from a clinical trial with the ClinicalTrials.gov Identifier: NCT02014870, first registered on December 5, 2013.

Characterisation of a wild-type influenza (A/H1N1) virus strain as an experimental challenge agent in humans.

BACKGROUND: Human challenge models using respiratory viruses such as influenza are increasingly utilised in the development of novel vaccines and anti-viral modalities and can provide preliminary evidence of protection before evaluation in field trials. We describe the results of a clinical study characterising an A/H1N1 influenza challenge virus in humans. METHODS: The challenge agent, influenza A/California/2009 (H1N1), was manufactured under cGMP conditions and characterised in accordance with regulatory guidelines. A dose-ascending open-label clinical study was conducted in 29 healthy young adults screened sero-negative to the challenge strain. Subjects were intranasally inoculated with three increasing doses of virus and physician-reported signs, subjected-reported symptoms, viral shedding and immunological responses were monitored. RESULTS: A dose-dependent increase in clinical signs and symptoms was observed with 75% of subjects developing laboratory-confirmed illness at the highest inoculum (3.5 × 10(6) TCID50). At the highest dose, physician or subject-reported signs of infection were classified as mild (all subjects), moderate (50%) and severe (16%) with peak symptoms recorded four days after infection. Clinical signs were correlated with nasal mucus weight (P < .001) and subject-reported symptoms (P < .001). Geometric mean peak viral shedding was log10 5.16 TCID50 and occurred three days after inoculation with a median duration of five days. The safety profile was such that physiological responses to viral infection were mainly restricted to the upper airways but were not of such severity to be of clinical concern. CONCLUSIONS: A highly characterised wild-type Influenza A/California/2009 (H1N1) virus manufactured for clinical use was shown to induce a good infectivity profile in human volunteers. This clinical challenge model can be used for evaluating potential efficacy of vaccines and anti-viral therapeutics. TRIAL REGISTRATION: NCT02014870.

A novel peptide-based pan-influenza A vaccine: a double blind, randomised clinical trial of immunogenicity and safety.

BACKGROUND: FP-01.1 is a novel synthetic influenza A vaccine consisting of six fluorocarbon-modified 35-mer peptides that encapsulate multiple CD4+ and CD8+ T-cell epitopes and is designed to induce an immune response across a broad population. METHODS: FP-01.1 was evaluated for safety and immunogenicity in a randomised, double-blind, placebo-controlled, dose-escalation, phase I clinical study in healthy adult volunteers (n=49). IFNγ ELISpot assays and multicolour flow cytometry were used to characterise the immune response. RESULTS: FP-01.1 was safe and well tolerated at all doses tested with a similar adverse event profile in actively vaccinated subjects compared with controls. Maximum immunogenicity was in the 150 µg/peptide dose group where a robust response (243 spots/million PBMC) was demonstrated in 75% subjects compared with 0% in placebo controls. All six peptides were immunogenic. FP-01.1 induced dual CD4+ and CD8+ T cell responses and vaccine-specific T cells cross-recognise divergent influenza strains. CONCLUSIONS: This first-in-human study showed that FP-01.1 has an acceptable safety and tolerability profile and generated robust anti-viral T cell responses in a high proportion of subjects tested. The results support the further clinical testing of FP-01.1 prior to clinical, proof-of-concept, live viral challenge studies.

OX40 interactions in gastrointestinal nematode infection.

The immune expulsion of gastrointestinal nematode parasites is usually associated with T helper type 2 (Th2) responses, but the effector mechanisms directly responsible for parasite loss have not been elucidated. The intestinal inflammatory response accompanying infection with gastrointestinal helminths is thought to be a contributory factor leading to the expulsion of the parasite. However, we have shown that the intestinal inflammation, which is controlled by interleukin (IL)-4, is not required for parasite expulsion. OX40-OX40 ligand (L) signals have been shown to be important for the development of Th2 immune responses but are also involved in a number of inflammatory diseases including those of the intestine. Here, we have investigated the effect of OX40 and OX40L fusion protein treatment on the induction of protective Th2 responses and enteropathy following infection with the gastrointestinal nematode Trichinella spiralis. Treatment with an OX40-immunoglobulin (Ig) blocking fusion protein resulted in enhanced expulsion of the parasite and an increase in the accompanying mastocytosis, despite unaltered levels of Th2 cytokines. Furthermore, there was a delay in the villus atrophy and crypt hyperplasia usually associated with this infection. In contrast, levels of Th2 cytokines were greatly up-regulated in mice treated with an OX40L-Ig activating fusion protein, yet the expulsion of the parasite and the enteropathy were unaffected. Therefore, OX40 ligation potentiates the Th2 response without enhancing host protective immune responses, whereas blocking the OX40-OX40L interaction enhances host protection without promoting Th2 cytokine responses during Trichinella spiralis infection.

Viral chemokine-binding proteins inhibit inflammatory responses and aortic allograft transplant vasculopathy in rat models.

BACKGROUND: Both CC and CXC chemokines direct monocyte and T-cell migration and activation at sites of vascular injury, but the relative contributions of each chemokine class to transplant vasculopathy development have not been defined. The nonselective C, CC, and CXC chemokine binding protein, M-T7, inhibits vasculopathy development after angioplasty and after renal transplant. We have assessed the effects of three viral chemokine-binding proteins with differing ranges of chemokine inhibition on plaque growth in rats after aortic allograft transplant. METHODS: One of two myxomaviral chemokine binding proteins, (1). M-T1, a selective CC chemokine inhibitor, or (2). M-T7, a nonselective chemokine-binding protein, was given immediately after transplant. A separate group was treated with the gamma68-herpesvirus protein, M3, a C, CC, CXC, and CX3C binding protein, with preferential CC binding. RESULTS: Intimal hyperplasia was significantly reduced at late times posttransplant after infusion of each chemokine-binding protein (P <0.05). Early inhibition of macrophage and T-cell invasion was associated with a late decrease in vasculopathy development. Infusion of an inactive myxomavirus protein did not inhibit plaque growth. Combined high-dose M-T1 and M-T7 did not reduce plaque growth or early cell invasion to a greater extent than either protein alone. Coinfusion of the CC chemokines macrophage chemoattractant protein-1 and macrophage inflammatory protein-1alpha neutralized M-T1 and M-T7 inhibition of monocyte invasion, respectively, suggesting a key role for CC chemokine-mediated cellular influx. CONCLUSION: Viral chemokine-modulating proteins effectively reduce aortic allograft vasculopathy, acting predominantly through inhibition of a CC chemokine-mediated response.

Development of vaccines to help treat drug dependence.

The social and economic consequences of drug addiction are immense. Although many methods are adopted to treat addiction, including therapeutic intervention and counseling, the long-term success rate has been limited and there continues to be a need for more effective treatments. A novel approach that has sparked a significant degree of interest recently is the use of vaccines designed to raise specific antibodies against drugs of abuse. Antibodies that prevent addictive substances crossing the blood-brain barrier may prove to be an effective mechanism that will help prevent relapse during efforts to abstain from the drug. Proof-of-principle for this approach has been established in numerous animal models. Currently a cocaine vaccine is in phase II clinical trials and, more recently, two vaccines to nicotine have entered phase I trials. Key efficacy trials are required to establish the true potential of these therapeutic vaccines.