Journal Article

Topical exposure to triclosan inhibits Th1 immune responses and reduces T cells responding to influenza infection in mice

Shane, Hillary L., Othumpangat, Sreekumar, Marshall, Nikki B., Weatherly, Lisa M., Blachere, Francoise, Baur, Rachel, Noti, John D., Anderson, Stacey E., Lukomska, Ewa

2020

Overview

Healthcare workers concurrently may be at a higher risk of developing respiratory infections and allergic disease, such as asthma, than the general public. Increased incidence of allergic diseases is thought to be caused, in part, due to occupational exposure to chemicals that induce or augment Th2 immune responses. However, whether exposure to these chemical antimicrobials can influence immune responses to respiratory pathogens is unknown. Here, we use a BALB/c murine model to test if the Th2-promoting antimicrobial chemical triclosan influences immune responses to influenza A virus. Mice were dermally exposed to 2% triclosan for 7 days prior to infection with a sub-lethal dose of mouse adapted PR8 A(H1N1) virus (50 pfu); triclosan exposure continued until 10 days post infection (dpi). Infected mice exposed to triclosan did not show an increase in morbidity or mortality, and viral titers were unchanged. Assessment of T cell responses at 10 dpi showed a decrease in the number of total and activated (CD44 hi ) CD4+ and CD8+ T cells at the site of infection (BAL and lung) in triclosan exposed mice compared to controls. Influenza-specific CD4+ and CD8+ T cells were assessed using MHCI and MHCII tetramers, with reduced populations, although not reaching statistical significance at these sites following triclosan exposure. Reductions in the Th1 transcription factor T-bet were seen in both activated and tetramer+ CD4+ and CD8+ T cells in the lungs of triclosan exposed infected mice, indicating reduced Th1 polarization and providing a potential mechanism for numerical reduction in T cells. Overall, these results indicate that the immune environment induced by triclosan exposure has the potential to influence the developing immune response to a respiratory viral infection and may have implications for healthcare workers who may be at an increased risk for developing infectious diseases.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adaptive Immunity - drug effects / Administration, Topical / Allergic diseases / Allergies / Animal models / Animals / Antiinfectives and antibacterials / Antimicrobial agents / Asthma / Biology and Life Sciences / CD4 antigen / CD4 lymphocytes / CD8 antigen / Chemicals / Cytokines / Disease control / Disease Models, Animal / Disease prevention / Epidemics / Exposure / Female / Health aspects / Health care / Health Personnel / Health risks / Humans / Immune response / Immune system / Immunology / Infections / Infectious diseases / Influenza / Influenza A / Influenza A Virus, H1N1 Subtype - immunology / Influenza, Human - immunology / Influenza, Human - prevention & control / Influenza, Human - virology / Lethal dose / Lungs / Lymphocytes / Lymphocytes T / Medical laboratories / Medical personnel / Medicine and Health Sciences / Mice / Morbidity / Occupational exposure / Occupational Exposure - adverse effects / Occupational health / Occupational health and safety / Occupational safety / Pandemics / Pathogens / People and Places / Physiological aspects / Public health / Research and Analysis Methods / Respiratory diseases / Risk factors / Th1 Cells - drug effects / Th1 Cells - immunology / Transcription factors / Triclosan / Triclosan - administration & dosage / Triclosan - adverse effects / Viruses / Workers