Repetitive Exposure to Bacteriophage Cocktails against Pseudomonas aeruginosa or Escherichia coli Provokes Marginal Humoral Immunity in Naïve Mice

Phage therapy of ventilator-associated pneumonia (VAP) is of great interest due to the rising incidence of multidrug-resistant bacterial pathogens. However, natural or therapy-induced immunity against therapeutic phages remains a potential concern. In this study, we investigated the innate and adaptive immune responses to two different phage cocktails targeting either Pseudomonas aeruginosa or Escherichia coli—two VAP-associated pathogens—in naïve mice without the confounding effects of a bacterial infection. Active or UV-inactivated phage cocktails or buffers were injected intraperitoneally daily for 7 days in C57BL/6J wild-type mice. Blood cell analysis, flow cytometry analysis, assessment of phage distribution and histopathological analysis of spleens were performed at 6 h, 10 days and 21 days after treatment start. Phages reached the lungs and although the phage cocktails were slightly immunogenic, phage injections were well tolerated without obvious adverse effects. No signs of activation of innate or adaptive immune cells were observed; however, both active phage cocktails elicited a minimal humoral response with secretion of phage-specific antibodies. Our findings show that even repetitive injections lead only to a minimal innate and adaptive immune response in naïve mice and suggest that systemic phage treatment is thus potentially suitable for treating bacterial lung infections

Preclinical Assessment of Bacteriophage Therapy against Experimental Acinetobacter baumannii Lung Infection

Respiratory infections caused by multidrug-resistant Acinetobacter baumannii are difficult to treat and associated with high mortality among critically ill hospitalized patients. Bacteriophages (phages) eliminate pathogens with high host specificity and efficacy. However, the lack of appropriate preclinical experimental models hampers the progress of clinical development of phages as therapeutic agents. Therefore, we tested the efficacy of a purified lytic phage, vB_AbaM_Acibel004, against multidrug-resistant A. baumannii clinical isolate RUH 2037 infection in immunocompetent mice and a human lung tissue model. Sham- and A. baumannii-infected mice received a single-dose of phage or buffer via intratracheal aerosolization. Group-specific differences in bacterial burden, immune and clinical responses were compared. Phage-treated mice not only recovered faster from infection-associated hypothermia but also had lower pulmonary bacterial burden, lower lung permeability, and cytokine release. Histopathological examination revealed less inflammation with unaffected inflammatory cellular recruitment. No phage-specific adverse events were noted. Additionally, the bactericidal effect of the purified phage on A. baumannii was confirmed after single-dose treatment in an ex vivo human lung infection model. Taken together, our data suggest that the investigated phage has significant potential to treat multidrug-resistant A. baumannii infections and further support the development of appropriate methods for preclinical evaluation of antibacterial efficacy of phages

A novel ACE2 decoy for both neutralization of SARS-CoV-2 variants and killing of infected cells

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led to millions of infections and deaths worldwide. As this virus evolves rapidly, there is a high need for treatment options that can win the race against new emerging variants of concern. Here, we describe a novel immunotherapeutic drug based on the SARS-CoV-2 entry receptor ACE2 and provide experimental evidence that it cannot only be used for (i) neutralization of SARS-CoV-2 in vitro and in SARS-CoV-2-infected animal models but also for (ii) clearance of virus-infected cells. For the latter purpose, we equipped the ACE2 decoy with an epitope tag. Thereby, we converted it to an adapter molecule, which we successfully applied in the modular platforms UniMAB and UniCAR for retargeting of either unmodified or universal chimeric antigen receptor-modified immune effector cells. Our results pave the way for a clinical application of this novel ACE2 decoy, which will clearly improve COVID-19 treatment

Aseptische Abfüllung biopharmazeutischer Prüfarzneimittel

Die aseptische Abfüllung klinischer Prüfarzneimittel (IMP) – insbesondere solche mit biotechnologisch hergestellten Wirkstoffkandidaten, wie z.B. Bakteriophagen, Viren oder Antikörpern bzw. Antikörperfragmenten – kann sich häufig als große Herausforderung herausstellen. Zwar besteht immer die Möglichkeit, sich an einen Lohnabfüller/Dienstleister zu wenden. Diesem fehlt es aber oft an Erfahrung mit dem neuen Wirkstoff oder die Abfüllung einer Kleinstcharge erscheint wenig lohnenswert und ist nur mit unverhältnismäßig hohem Mehraufwand umsetzbar. Vielversprechende neue Wirkstoffe landen nach der Prozessentwicklungsphase häufig in einer Sackgasse, Projekte drohen gebremst oder vollständig eingestellt zu werden. Deshalb hat die Pharmazeutische Biotechnologie des Fraunhofer Institut für Toxikologie und Experimentelle Medizin (ITEM) eine aseptische Abfüllung für Kleinstchargen solcher Produkte in Vials und Glasampullen etabliert. Die neue Sterilabfüllung ermöglicht schnellen, flexiblen und wirtschaftlichen Zugang zu klinischem Prüfmaterial

Mechanisms underlying epigenetic and transcriptional heterogeneity in Chinese hamster ovary (CHO) cell lines

Background: Recombinant cell lines developed for therapeutic antibody production often suffer instability or lose recombinant protein expression during long-term culture. Heterogeneous gene expression among cell line subclones may result from epigenetic modifications of DNA or histones, the protein component of chromatin. We thus investigated in such cell lines, DNA methylation and the chromatin environment along the human eukaryotic translation elongation factor 1 alpha 1 (EEF1A1) promoter in an antibody protein-expression vector which was integrated into the Chinese hamster ovary (CHO) cell line genome. Results: We analyzed four PT1-CHO cell lines which exhibited losses of protein expression at advanced passage number (>P35) growing in adherent conditions and in culture medium with 10 % FCS. These cell lines exhibited different integration sites and transgene copy numbers as determined by fluorescence in situ hybridization (FISH) and quantitative PCR (qPCR), respectively. By qRT-PCR, we analyzed the recombinant mRNA expression and correlated it with DNA methylation and with results from various approaches interrogating the chromatin landscape along the EEF1A1 promoter region. Each PT1-CHO cell line displayed specific epigenetic signatures or chromatin marks correlating with recombinant mRNA expression. The cell line with the lowest recombinant mRNA expression (PT1-1) was characterized by the highest nucleosome occupancy and displayed the lowest enrichment for histone marks associated with active transcription. In contrast, the cell line with the highest recombinant mRNA expression (PT1-55) exhibited the highest numbers of formaldehyde-assisted isolation of regulatory elements (FAIRE)-enriched regions, and was marked by enrichment for histone modifications H3K9ac and H3K9me3. Another cell line with the second highest recombinant mRNA transcription and the most stable protein expression (PT1-7) had the highest enrichments of the histone variants H3.3 and H2A.Z, and the histone modification H3K9ac. A further cell line (PT1-30) scored the highest enrichments for the bivalent marks H3K4me3 and H3K27me3. Finally, DNA methylation made a contribution, but only in the culture medium with reduced FCS or in a different expression vector. Conclusions: Our results suggest that the chromatin state along the EEF1A1 promoter region can help predict recombinant mRNA expression, and thus may assist in selecting desirable clones during cell line development for protein production

Additional file 6: Figure S6. of Mechanisms underlying epigenetic and transcriptional heterogeneity in Chinese hamster ovary (CHO) cell lines

ChIP enrichments in PT1-CHO cell lines. (A) H2A enrichments in the different PT1-CHO cell lines and four qPCR primer pairs. The data were analyzed by two-tailed ANOVA, which found statistically significant differences in H2A enrichment (H2A nucleosome occupancy) among the cell lines (** P = 0.0070), but not differences resulting with the qPCR primers (nucleosome). Results are presented as % input calculated from Ct values, and the means and SEM of n = 12 independent experiments involving four primer pairs along two predicted nucleosome positions in the EEF1A1 promoter region. Also shown are the qPCR values obtained in the four primer pairs for IgG, which served as control for the ChIP experiment. (B) ChIP with H3K27me3 and control IgG obtained after qPCR with four primer pairs. (C, E, F, G) ChIP with H2A.Z, H3K9me3, and control IgG obtained by % input DNA, left panels), and H2A.Z and H3K9me3 after further normalization to H2A (right panels). Data represent means and SEM of n = 3 independent experiments. (TIF 799 kb

Safety, efficacy and repeatability of a novel house dust mite allergen challenge technique in the Fraunhofer allergen challenge chamber

BACKGROUND: Efficacy testing of immunotherapy in field studies is often hampered by variation of airborne allergens. Standardized allergen exposure in challenge chamber settings might be an alternative. Therefore, we developed a universal technique to create an atmosphere loaded with allergen particles of adjustable size from aqueous solutions of licensed allergen extracts. OBJECTIVE: The aim of this study was to apply this technique and test the safety and efficacy of challenges with house dust mite (HDM) allergen in the Fraunhofer allergen challenge chamber. METHODS: Aerosol particles carrying HDM allergen were produced by spray-drying of an aqueous solution containing HDM allergen and lactose. In a monocenter, placebo-controlled, single-blind, dose-escalation pilot study, 18 subjects with perennial allergic rhinitis and sensitization to HDM were exposed to HDM allergen for 4 h at either 250, 500, 1000 SQE/m3 or lactose alone (0 SQE/m3 ) 7 days apart. The dose of 500 SQE/m(3) was repeated to investigate reproducibility. Total nasal symptom score (TNSS) was the primary endpoint. RESULTS: Exposure to HDM increased TNSS (mean +/- SD) to 3.4 +/- 1.8, 3.3 +/- 2.1, and 3.6 +/- 2.0 at 250, 500 and 1000 SQE/m3 , respectively, while lactose alone did not change TNSS (0.7 +/- 0.6). The results were reproducible at 500 SQE/m3 . Pulmonary function and adverse event frequency did not change with escalation of allergen dose. CONCLUSION: This HDM allergen particle generation is safe, specific and reproducible and can therefore be used for efficacy testing of immunotherapy and for basic clinical research

Repetitive Exposure to Bacteriophage Cocktails against Pseudomonas aeruginosa or Escherichia coli Provokes Marginal Humoral Immunity in Naïve Mice

Phage therapy of ventilator-associated pneumonia (VAP) is of great interest due to the rising incidence of multidrug-resistant bacterial pathogens. However, natural or therapy-induced immunity against therapeutic phages remains a potential concern. In this study, we investigated the innate and adaptive immune responses to two different phage cocktails targeting either Pseudomonas aeruginosa or Escherichia coli—two VAP-associated pathogens—in naïve mice without the confounding effects of a bacterial infection. Active or UV-inactivated phage cocktails or buffers were injected intraperitoneally daily for 7 days in C57BL/6J wild-type mice. Blood cell analysis, flow cytometry analysis, assessment of phage distribution and histopathological analysis of spleens were performed at 6 h, 10 days and 21 days after treatment start. Phages reached the lungs and although the phage cocktails were slightly immunogenic, phage injections were well tolerated without obvious adverse effects. No signs of activation of innate or adaptive immune cells were observed; however, both active phage cocktails elicited a minimal humoral response with secretion of phage-specific antibodies. Our findings show that even repetitive injections lead only to a minimal innate and adaptive immune response in naïve mice and suggest that systemic phage treatment is thus potentially suitable for treating bacterial lung infections

Phage Therapy in Germany—Update 2023

Bacteriophage therapy holds promise in addressing the antibiotic-resistance crisis, globally and in Germany. Here, we provide an overview of the current situation (2023) of applied phage therapy and supporting research in Germany. The authors, an interdisciplinary group working on patient-focused bacteriophage research, addressed phage production, phage banks, susceptibility testing, clinical application, ongoing translational research, the regulatory situation, and the network structure in Germany. They identified critical shortcomings including the lack of clinical trials, a paucity of appropriate regulation and a shortage of phages for clinical use. Phage therapy is currently being applied to a limited number of patients as individual treatment trials. There is presently only one site in Germany for large-scale good-manufacturing-practice (GMP) phage production, and one clinic carrying out permission-free production of medicinal products. Several phage banks exist, but due to varying institutional policies, exchange among them is limited. The number of phage research projects has remarkably increased in recent years, some of which are part of structured networks. There is a demand for the expansion of production capacities with defined quality standards, a structured registry of all treated patients and clear therapeutic guidelines. Furthermore, the medical field is still poorly informed about phage therapy. The current status of non-approval, however, may also be regarded as advantageous, as insufficiently restricted use of phage therapy without adequate scientific evidence for effectiveness and safety must be prevented. In close coordination with the regulatory authorities, it seems sensible to first allow some centers to treat patients following the Belgian model. There is an urgent need for targeted networking and funding, particularly of translational research, to help advance the clinical application of phages