OM-85 Broncho-Vaxom®, a Bacterial Lysate, Reduces SARS-CoV-2 Binding Proteins on Human Bronchial Epithelial Cells

OM85 ameliorates bleomycin-induced pulmonary fibrosis in mice by inhibiting Notch expression and modulating the IFN-γ/IL-4 ratio

Th1/Th2 balances may play a vital role in the processes of inflammation and fibrosis. The Th1/Th2 paradigm can be evaluated by representing IFN-γ for Th1 and IL-4 for Th2. OM-85 BV encouraged preferential development of the Th1-type immunity characterized by amplified IFN-γ and decreased IL-4 production. This study aimed to evaluate the inhibitory effect of OM85 on bleomycin (BLM)-induced pulmonary fibrosis in C57 and its possible mechanisms. In vitro experiments demonstrated that OM85 exhibited no significant toxicity to HELF cells. OM-85 inhibited the TGF-β1-induced protein expression of Notch1 and Hes1 and reduced the fibrosis-related marker profiles, such as collagen I, collagen III, fibronectin, P21, and α-SMA, following TGF-β1 treatment of these cells. Immunofluorescence also revealed that OM-85 decreased the expression of α-SMA induced by TGF-β1 in HELF cells. In the vivo experiments, a pulmonary fibrosis model was established by administering three intratracheal doses of BLM (1 mg/kg). The BLM-OM85 group was exposed to an aerosol containing 10.5 mg of OM-85 dissolved in 10 mL of sterile PBS on days 42, 44, 46, 49, 51, and 53. BLM-induced pulmonary fibrosis, leading to increased levels of lung hydroxyproline, total cell count, macrophages, neutrophils, lymphocytes, and the expression of TGF-β1 as well as Notch1 and Hes1 in lung tissue, along with fibrosis-associated proteins such as collagen I, collagen III, fibronectin, P21, and α-SMA. Additionally, the Th1 response was suppressed, as evidenced by decreased IFN-γ in the bronchoalveolar lavage fluid (BALF), while the Th2 response was amplified, marked by increased IL-4 levels in BALF. Moreover, morphological assessments showed that BLM caused increased Ashcroft scores, relative collagen content, and an expanded damaged area, as well as an increased optical density (OD) of collagen I. The administration of OM-85 significantly mitigated these effects. These findings suggest that OM-85 holds therapeutic potential for BLM-induced pulmonary fibrosis in female C57 mice, partly due to the inhibition of Notch1 and Hes1 expression and the modulation of the IFN-γ/IL-4 ratio.

Immunological Insights and Therapeutic Advances in COPD: Exploring Oral Bacterial Vaccines for Immune Modulation and Clinical Improvement

Chronic obstructive pulmonary disease (COPD) is a prevalent chronic condition associated with substantial global morbidity and mortality. Primarily caused by prolonged exposure to harmful agents such as dust and gases, COPD is characterized by persistent airflow limitation, clinically manifesting as chronic cough, sputum production, and dyspnea. The disease course alternates between stable phases and exacerbations, with the latter often associated with pathogenic colonization of the respiratory tract. This review examines the immunological underpinnings of COPD, emphasizing the interplay between innate and adaptive immunity in disease pathogenesis. Dysregulated immune responses to environmental factors perpetuate chronic inflammation, resulting in progressive pulmonary epithelial damage and connective tissue hyperplasia, which compromise gas exchange. Exacerbations further exacerbate respiratory failure, aggravating patient symptoms and accelerating disease progression. Despite advances in COPD management, effective therapeutic options remain limited. Current treatments primarily aim to alleviate symptoms, reduce immune activation, and manage infections, yet many patients experience suboptimal outcomes. This review highlights the potential of novel therapeutic approaches targeting immune system cells and pathways. In particular, it explores the promise of oral bacterial vaccines as immunomodulatory agents to enhance immune responses and improve clinical outcomes in COPD, addressing critical gaps in current treatment paradigms.

Oral Bacterial Lysate OM-85: Advances in Pharmacology and Therapeutics

Background

Bacterial lysates are known for having immunomodulatory properties and have been used mainly for the prevention and treatment of respiratory tract infections (RTIs). However, rigorous studies are needed to confirm the clinical efficacy of bacterial lysates with various bacterial antigen components, preparation methods, administration routes and course of treatment. OM-85, an oral standardized lysate prepared by alkaline lysis of 21 strains from 8 species of common respiratory tract pathogens, is indicated as immunotherapy for prevention of recurrent RTIs and acute infectious exacerbations of chronic bronchitis. OM-85 acts on multiple innate and adaptive immune targets and can restore type 1 helper T (Th1)/Th2 balance. Sporadic studies have shown advances in pharmacology and therapeutics of OM-85, and thus an update review is necessary.

Methods

Literature was retrieved by searching PubMed, Web of science, Embase, CNKI, and Full Text Database of Chinese Medical Journals.

Results

New roles of OM-85 were discovered in prevention and treatment of lung cancer, pulmonary tuberculosis, SARS-CoV-2 infection, allergic rhinitis, pulmonary fibrosis, atopic dermatitis, and nephrotic syndrome. Pharmacoeconomic values of OM-85 were demonstrated in prophylaxis and treatment of RTIs, chronic obstructive pulmonary disease, asthma, chronic bronchitis, rhinosinusitis and allergic rhinitis. Two consecutive courses of OM-85 (6 or 12 months apart) could prevent recurrent RTIs in children. Maternal OM-85 treatment could offer benefits for offspring. Product-specific response was observed. The efficacy of OM-85 may be associated with patient's characteristics (eg, severity of the disease, age, immune response pattern, malignancy risk stratification).

Conclusion

OM-85 can improve effectiveness of standard care for some primary diseases, and carry significant pharmacoeconomic implications. The benefits shown by OM-85 in vitro and in vivo, when extrapolated to humans, are exciting but also require caution. Individualized treatment may need to be considered. It is necessary to compare the efficacy and safety of various bacterial lysate preparations.

Broncho-Vaxom Attenuates Lipopolysaccharide-Induced Inflammation in a Mouse Model of Acute Lung Injury

Acute lung injury (ALI) is a condition associated with acute respiratory failure, resulting in significant morbidity and mortality. It involves cellular changes such as disruption of the alveolar-capillary membrane, excessive neutrophil migration, and release of inflammatory mediators. Broncho-Vaxom® (BV), a lyophilized product containing cell membrane components derived from eight bacteria commonly found in the respiratory tract, is known for its potential to reduce viral and bacterial lung infections. However, the specific effect of BV on ALI has not been clearly defined. This study explored the preventive effects of BV and its underlying mechanisms in a lipopolysaccharide (LPS)-induced ALI mouse model. Oral BV (1 mg/kg) gavage was administered one hour before the intratracheal injection of LPS to evaluate its preventive effect on the ALI model. The pre-administration of BV significantly mitigates inflammatory parameters, including the production of inflammatory mediators, macrophage infiltration, and NF-κB activation in lung tissue, and the increase in inflammatory cells in bronchoalveolar lavage fluid (BALF). Moreover, BV (3 μg/mL) pretreatment reduced the expression of M1 macrophage markers, interleukins (IL-1β, IL-6), tumor necrosis factor α, and cyclooxygenase-2, which are activated by LPS, in both mouse alveolar macrophage MH-S cells and human macrophage THP-1 cells. These findings showed that BV exhibits anti-inflammatory effects by suppressing inflammatory mediators through the NF-κB pathway, suggesting its potential to attenuate bronchial and pulmonary inflammation.

Secretory IgA and course of COVID-19 in patients receiving a bacteria-based immunostimulant agent in addition to background therapy

Mucosal immunity plays a major role not only in the prevention but probably also in the outcomes of COVID-19. An enhanced production of secretory immunoglobulin A (sIgA) might contribute to the activation of the immune response mechanisms. To assess the levels of sIgA produced by epithelial cells in the nasal and pharyngeal mucosa and those measured in salivary gland secretions and to study the course of COVID-19 following the combined scheme of intranasal and subcutaneous administration of a bacteria-based immunostimulant agent. This study included 69 patients, aged between 18 and 60, who had moderate COVID-19 infection. They were divided into two groups: Group 1 (control group) included 39 patients who received only background therapy, and Group 2 was made up of 30 patients who received background therapy in combination with the Immunovac VP4 vaccine, a bacteria-based immunostimulant agent, which was given for 11 days starting from the day of admission to hospital. The levels of sIgA were measured by ELISA in epithelial, nasal and pharyngeal swabs, and salivary gland secretions at baseline and on days 14 and 30. The combined scheme of intranasal and subcutaneous administration of the Immunovac VP4 vaccine in the complex therapy of patients with COVID-19 is accompanied by increased synthesis of sIgA in nasal and pharyngeal swabs, more intense decrease in the level of C-reactive protein (CRP) and reduction in the duration of fever and length of hospitalization compared to the control group. Prescribing a immunostimulant agent containing bacterial ligands in complex therapy for COVID-19 patients helps to enhance mucosal immunity and improves the course of the disease.

Effect of respiratory tract co-colonizers on initial attachment of Neisseria meningitidis

Respiratory tract is a complex system comprising of unique microbiota inhabitants. Neisseria meningitidis, Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa and Klebsiella pneumoniae are few prevalent bacteria in the community composition during lung infections. Although, N. meningitidis resides asymptomatically in nasopharynx of the human host, it can cause fatal infections like meningitis. However, factors affecting transit from carriage to symptomatic infection are not well understood. Various host metabolites and environmental conditions affect the virulence of bacteria. Here, we report that presence of co-colonizers significantly reduces the initial attachment of N. meningitidis to A549 nasopharyngeal epithelial cells. Further, significant decrease in invasion to A549 nasopharyngeal epithelial cells was observed. Moreover, survival in J774A.1 murine macrophage also increases significantly when conditioned media (CM) from S. pyogenes and L. rhamnosus is used for culturing N. meningitidis. The increase in survival could be attributed to increased capsule synthesis. The gene expression studies revealed increased expression of siaC and ctrB in CM prepared from the growth S. pyogenes and L. rhamnosus. Overall, the results suggest change in the virulence of N. meningitidis is assisted by lung microbiota.

Modulation of innate immunity in airway epithelium for host-directed therapy

Innate immunity of the mucosal surfaces provides the first-line defense from invading pathogens and pollutants conferring protection from the external environment. Innate immune system of the airway epithelium consists of several components including the mucus layer, mucociliary clearance of beating cilia, production of host defense peptides, epithelial barrier integrity provided by tight and adherens junctions, pathogen recognition receptors, receptors for chemokines and cytokines, production of reactive oxygen species, and autophagy. Therefore, multiple components interplay with each other for efficient protection from pathogens that still can subvert host innate immune defenses. Hence, the modulation of innate immune responses with different inducers to boost host endogenous front-line defenses in the lung epithelium to fend off pathogens and to enhance epithelial innate immune responses in the immunocompromised individuals is of interest for host-directed therapy. Herein, we reviewed possibilities of modulation innate immune responses in the airway epithelium for host-directed therapy presenting an alternative approach to standard antibiotics.

The OM-85 bacterial lysate: a new tool against SARS-CoV-2?

The emergence of SARS-CoV-2, a novel coronavirus, caused the global Coronavirus disease of 2019 (COVID-19) pandemic. Because SARS-CoV-2 mutates rapidly, vaccines that induce immune responses against viral components critical for target cell infection strongly mitigate but do not abrogate viral spread, and disease rates remain high worldwide. Complementary treatments are therefore needed to reduce the frequency and/or severity of SARS-CoV-2 infections. OM-85, a standardized lysate of 21 bacterial strains often found in the human airways, has immuno-modulatory properties and is widely used empirically in Europe, South America and Asia for the prophylaxis of recurrent upper airway infections in adults and children, with excellent safety profiles. In vitro studies from our laboratory recently demonstrated that OM-85 inhibits SARS-CoV-2 epithelial cell infection by downregulating SARS-CoV-2 receptor expression, raising the possibility that this bacterial extract might eventually complement the current COVID-19 therapeutic toolkit. Here we discuss how our results and those from other groups are fostering progress in this emerging field of research.

Vascular Endothelial Glycocalyx Damage and Potential Targeted Therapy in COVID-19

COVID-19 is a highly infectious respiratory disease caused by a new coronavirus known as SARS-CoV-2. COVID-19 is characterized by progressive respiratory failure resulting from diffuse alveolar damage, inflammatory infiltrates, endotheliitis, and pulmonary and systemic coagulopathy forming obstructive microthrombi with multi-organ dysfunction, indicating that endothelial cells (ECs) play a central role in the pathogenesis of COVID-19. The glycocalyx is defined as a complex gel-like layer of glycosylated lipid–protein mixtures, which surrounds all living cells and acts as a buffer between the cell and the extracellular matrix. The endothelial glycocalyx layer (EGL) plays an important role in vascular homeostasis via regulating vascular permeability, cell adhesion, mechanosensing for hemodynamic shear stresses, and antithrombotic and anti-inflammatory functions. Here, we review the new findings that described EGL damage in ARDS, coagulopathy, and the multisystem inflammatory disease associated with COVID-19. Mechanistically, the inflammatory mediators, reactive oxygen species (ROS), matrix metalloproteases (MMPs), the glycocalyx fragments, and the viral proteins may contribute to endothelial glycocalyx damage in COVID-19. In addition, the potential therapeutic strategies targeting the EGL for the treatment of severe COVID-19 are summarized and discussed.

Airway Administration of Bacterial Lysate OM-85 Protects Mice Against Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is a seasonal pathogen responsible for the highest percentage of viral bronchiolitis in pediatric patients. There are currently no vaccine available and therapeutic methods to mitigate the severity of RSV bronchiolitis are limited. OM-85, an oral standardized bacterial lysate isolated from human respiratory strains and widely used to prevent recurrent infections and/or exacerbations in populations at risk, has been shown to be effective and safe in children and adults. Here, we demonstrate that airway administration of OM-85 in Balb/c mice prior to infection prevents RSV-induced disease, resulting in inhibition of viral replication associated with less perivascular and peribronchial inflammation in the lungs. These protective effects are dose and time-dependent with complete protection using 1mg dose of OM-85 only four times intranasally. Mechanistic insights using this topical route in the airways revealed increased alveolar macrophages, a selective set of tolerogenic DCs, Treg and Th1 expansion in the lung, even in the absence of infection, contributing to a better Th1/Th2 balance and preventing ILC2 recruitment in the airways and associated inflammatory sequelae. OM-85 preventive treatment also improved antiviral response by increasing IFNβ and its responsive genes in the lung. In vitro, OM-85 protects against RSV infection in a type I interferon pathway. Our animal model data suggest that intranasal use of OM-85 should be considered as a potential prophylactic product to prevent RSV bronchiolitis once human studies confirm these findings.

The SARS-CoV-2 Entry Inhibition Mechanisms of Serine Protease Inhibitors, OM-85, Heparin and Soluble HS Might Be Linked to HS Attachment Sites

This article discusses the importance of D-xylose for fighting viruses (especially SARS-CoV-2) that use core proteins as receptors at the cell surface, by providing additional supporting facts that these viruses probably bind at HS/CS attachment sites (i.e., the hydroxyl groups of Ser/Thr residues of the core proteins intended to receive the D-xylose molecules to initiate the HS/CS chains). Essentially, the additional supporting facts, are: some anterior studies on the binding sites of exogenous heparin and soluble HS on the core proteins, the inhibition of the viral entry by pre-incubation of cells with heparin, and additionally, corroborating studies about the mechanism leading to type 2 diabetes during viral infection. We then discuss the mechanism by which serine protease inhibitors inhibit SARS-CoV-2 entry. The biosynthesis of heparan sulfate (HS), chondroitin sulfate (CS), dermatan sulfate (DS), and heparin (Hep) is initiated not only by D-xylose derived from uridine diphosphate (UDP)-xylose, but also bioactive D-xylose molecules, even in situations where cells were previously treated with GAG inhibitors. This property of D-xylose shown by previous anterior studies helped in the explanation of the mechanism leading to type 2 diabetes during SARS-CoV-2 infection. This explanation is completed here by a preliminary estimation of xyloside GAGs (HS/CS/DS/Hep) in the body, and with other previous studies helping to corroborate the mechanism by which the D-xylose exhibits its antiglycaemic properties and the mechanism leading to type 2 diabetes during SARS-CoV-2 infection. This paper also discusses the confirmatory studies of regarding the correlation between D-xylose and COVID-19 severity.

Can bacterial lysates be useful in prevention of viral respiratory infections in childhood? The results of experimental OM-85 studies

Respiratory tract infections (RTI) are mainly viral in origin and among the leading cause of childhood morbidity globally. Associated wheezing illness and asthma are still a clear unmet medical need. Despite the continuous progress in understanding the processes involved in their pathogenesis, preventive measures and treatments failed to demonstrate any significant disease-modifying effect. However, in the last decades it was understood that early-life exposure to microbes, may reduce the risk of infectious and allergic disorders, increasing the immune response efficacy. These results suggested that treatment with bacterial lysates (BLs) acting on gut microbiota, could promote a heterologous immunomodulation useful in the prevention of recurrent RTIs and of wheezing inception and persistence. This hypothesis has been supported by clinical and experimental studies showing the reduction of RTI frequency and severity in childhood after oral BL prophylaxis and elucidating the involved mechanisms. OM-85 is the product whose anti-viral effects have been most extensively studied in vitro, animal, and human cell studies and in translational animal infection/disease models. The results of the latter studies, describing the potential immune training-based activities of such BL, leading to the protection against respiratory viruses, will be reported. In response to human rhinovirus, influenza virus, respiratory syncytial virus and severe acute respiratory coronavirus-2, OM-85 was effective in modulating the structure and the functions of a large numbers of airways epithelial and immune cells, when administered both orally and intranasally.