Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a public health concern due to infections with new SARS-CoV-2 variants. Therefore, finding effective preventive and therapeutic treatments against all SARS-CoV-2 variants is of great interest. In this study, we examined the capacity of eucalyptus essential oil (EEO) and eucalyptol (EOL) to prevent SARS-CoV-2 infection, using as a model SARS-CoV-2 Spike pseudotyped lentivirus (SARS-CoV-2 pseudovirus) and 293T cells transfected with human angiotensin-converting enzyme 2 (hACE2-293T cells). First, we determined the cytotoxicity of EEO and EOL using the MTT colorimetric assay, selecting non-cytotoxic concentrations ≤ 0.1% (v/v) for further analysis. Subsequently, we evaluated the capacity of EEO and EOL in cell cultures to preclude infection of hACE2-293T cells by SARS-CoV-2 pseudovirus, using a luciferase-based assay. We found that EEO and EOL significantly reduced SARS-CoV-2 pseudovirus infection, obtaining IC₅₀ values of 0.00895% and 0.0042% (v/v), respectively. Likewise, EEO and EOL also reduced infection by vesicular stomatitis virus (VSV) pseudovirus, although higher concentrations were required. Hence, EEO and EOL may be able to inhibit SARS-CoV-2 infection, at least partially, through a Spike-independent pathway, supporting the implementation of aromatherapy with these agents as a cost-effective antiviral measure.

Background: Human rhinoviruses (HRVs) are the leading cause of upper respiratory tract infections, responsible for over half of all such infections. Infection rates among young children can reach as high as 8-12 episodes per year. While HRV infections typically result in mild common colds, they can also lead to more severe respiratory conditions, often in conjunction with bacterial coinfections. In addition, HRVs are implicated in the exacerbation of obstructive respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD). T-cell responses play a crucial role in the immune defense against HRV. However, in patients with obstructive respiratory diseases, altered or dysregulated T-cell responses to HRV may not only fail to efficiently eliminate the virus but can also exacerbate inflammation and airway remodeling. Therefore, a deeper understanding of T-cell–mediated responses in the context of HRV infection, especially in vulnerable populations like those with COPD, is critical. It can provide new insights into mechanisms of both protection and disease exacerbation, potentially guiding the development of targeted therapies or vaccines that enhance protective immunity while minimizing harmful inflammation. Objective: This study aims to (1) determine the population-wide coverage of HRV-specific T-cell responses, (2) characterize HRV-specific T-cell recall responses in disease cohorts compared to age-match healthy controls, and (3) identify biomarkers of protection and susceptibility within disease cohorts through a comparative analysis. Methods: Participants with asthma and those with COPD, aged 5-15 and 40-70 years, respectively, will be recruited alongside healthy age-matched controls. Peripheral blood samples will be collected following informed consent from adult participants and from parents or guardians of minors, as applicable. Clinical, demographic, immunological, and genetic responses will be assessed both prior to and following in vitro stimulation with a pool of HRV-specific T-cell epitopes. Flow cytometry and functional assays will be used to analyze T-cell responses to HRV epitopes in the context of obstructive respiratory diseases. Results: This study was funded in January 2023 by the Ministry of Science and Innovation of Spain. The primary aim of the study was achieved within the same year. Recruitment for the secondary and tertiary aims is currently ongoing. Preliminary findings highlight the potential significance of HRV-specific T-cell responses in individuals with asthma and those with COPD. A detailed characterization of these immune responses will provide critical insights into host-pathogen interactions and may serve as a foundation for the development of effective T-cell–based vaccines or immunotherapies targeting HRV. Conclusions: Here, we present an ethically approved study protocol for an observational and exploratory study investigating a novel epitope-based vaccine targeting HRV, with a focus on pediatric asthma and adult COPD cohort populations. International Registered Report Identifier (IRRID): DERR1-10.2196/73383

Lamiaceae and Asteraceae plant species have been widely used in Mediterranean ethnomedicine for gastrointestinal disorders. They are also known for their antioxidant, anti-inflammatory, anti-bacterial, anti-parasite, and anti-virus properties. Giardia duodenalis is the most prevalent intestinal protozoon in children and young dogs worldwide. Its zoonotic potential and frequent therapeutic failures with nitroimidazoles underscore the urgent need for alternative treatments. This study investigated the antigiardial activity of essential oils (EOs) from 22 medicinal plants belonging to Lamiaceae and Asteraceae, together with their major constituents. EO composition was determined by a metabolomic approach (GC-MS). Parasite metabolic activity was assessed using the MTT assay, and ultrastructural changes were examined by Transmission Electron Microscopy. The strongest antigiardial effects were observed with Lavandula luisieri, Thymus vulgaris, Mentha suaveolens, Satureja montana (IC₅₀ <25), L. lanata, and T. zygis, (IC₅₀= 27.9-71.5 µg/ml). The highest selective indexes were obtained with γ-terpinene, caryophyllene oxide, carvacrol and thymol (SI≥1.3-2.4). Synergistic interactions were detected with linalyl acetate and linalool (present in Lavandula EOs), linalyl acetate with ρ-cymene or thymol, or combinations of ρ-cymene, γ-terpinene, thymol, and carvacrol (present in Satureja EOs). Transmission Electron Microscopy revealed membranolysis, enlarged periplasmic vacuoles, and cytoplasmic loss in trophozoites exposed to γ-terpinene after 1 h. These findings provide phytotherapeutic evidence supporting essential oils from Lavandula, Mentha, Thymus, and Satureja as promising antigiardial agents. Their main components γ-terpinene, caryophyllene oxide, carvacrol and thymol could have potential applications in veterinary parasitology.

Viral infections, particularly by rhinoviruses (RVs), represent major triggers of acute exacerbations in chronic obstructive pulmonary disease (COPD). However, the role of RV-specific T cell responses in COPD remains poorly characterized. Here, we investigated T cell recall responses to conserved RV-specific T cell epitopes in COPD patients and age-matched healthy controls using activation-induced marker and intracellular cytokine staining assays. The frequency of RV-specific CD4⁺ T cells was increased in COPD patients compared with healthy participants. RV-specific CD8⁺ T cells also tended to be increased in COPD participants, although the differences did not reach statistical significance. Functional T cell responses to RV-specific epitopes were biased toward IFN-γ and TNF-α production in COPD and healthy participants, with no significant differences between groups. Accordingly, there is a degree of functional dissociation between enhanced RV-specific CD4⁺ T cell recognition and cytokine responses in COPD. A modest inverse correlation, yet not statistically significant (p = 0.066), was observed between IFN-γ-producing CD4⁺ T cells and disease severity, as assessed by FEV₁. Collectively, our findings suggest that T cell responses to conserved RV-specific epitopes are unlikely to be major drivers of COPD immunopathology, supporting their potential relevance for epitope-vaccine development in COPD.

BACKGROUND Human rhinoviruses (HRVs) are the leading cause of upper respiratory tract infections, responsible for over half of all such infections. Infection rates among young children can reach as high as 8-12 episodes per year. While HRV infections typically result in mild common colds, they can also lead to more severe respiratory conditions, often in conjunction with bacterial coinfections. In addition, HRVs are implicated in the exacerbation of obstructive respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD). T-cell responses play a crucial role in the immune defense against HRV. However, in patients with obstructive respiratory diseases, altered or dysregulated T-cell responses to HRV may not only fail to efficiently eliminate the virus but can also exacerbate inflammation and airway remodeling. Therefore, a deeper understanding of T-cell–mediated responses in the context of HRV infection, especially in vulnerable populations like those with COPD, is critical. It can provide new insights into mechanisms of both protection and disease exacerbation, potentially guiding the development of targeted therapies or vaccines that enhance protective immunity while minimizing harmful inflammation. OBJECTIVE This study aims to (1) determine the population-wide coverage of HRV-specific T-cell responses, (2) characterize HRV-specific T-cell recall responses in disease cohorts compared to age-match healthy controls, and (3) identify biomarkers of protection and susceptibility within disease cohorts through a comparative analysis. METHODS Participants with asthma and those with COPD, aged 5-15 and 40-70 years, respectively, will be recruited alongside healthy age-matched controls. Peripheral blood samples will be collected following informed consent from adult participants and from parents or guardians of minors, as applicable. Clinical, demographic, immunological, and genetic responses will be assessed both prior to and following in vitro stimulation with a pool of HRV-specific T-cell epitopes. Flow cytometry and functional assays will be used to analyze T-cell responses to HRV epitopes in the context of obstructive respiratory diseases. RESULTS This study was funded in January 2023 by the Ministry of Science and Innovation of Spain. The primary aim of the study was achieved within the same year. Recruitment for the secondary and tertiary aims is currently ongoing. Preliminary findings highlight the potential significance of HRV-specific T-cell responses in individuals with asthma and those with COPD. A detailed characterization of these immune responses will provide critical insights into host-pathogen interactions and may serve as a foundation for the development of effective T-cell–based vaccines or immunotherapies targeting HRV. CONCLUSIONS Here, we present an ethically approved study protocol for an observational and exploratory study investigating a novel epitope-based vaccine targeting HRV, with a focus on pediatric asthma and adult COPD cohort populations. INTERNATIONAL REGISTERED REPORT DERR1-10.2196/73383