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About our research interests

Rachel McLoughlin is an Irish Immunologist whose research into host-pathogen interactions has made a significant international impact and has directly informed development of next-generation vaccines to treat antimicrobial resistant bacterial infections. She is currently Professor in Immunology at the School of Biochemistry and Immunology at Trinity College Dublin (TCD). She received her PhD in Immunology from the University of Wales College of Medicine, Cardiff, UK and undertook postdoctoral training at the School of Biosciences, Cardiff University and Brigham and Women’s Hospital, Boston, USA before obtaining a faculty position as Assistant Professor in Medicine at Harvard Medical School. In 2010 she was awarded a Wellcome Trust Career Development Award and moved to Trinity College Dublin where she established the Host Pathogen Interactions Group within the School of Biochemistry and Immunology. Since then, she has established an international reputation as one of the leading immunologists working in the field of Staphylococcal biology and has mentored multiple post-graduate and post-doctoral researchers in the field of host-pathogen interactions.

The ultimate goal of the research in the Host Pathogen Interactions Group is to further understand how the host immune system responds to and is manipulated by specific bacteria that are contributing to the global burden of antimicrobial resistance (AMR) infection. Knowledge gained from these endeavours will directly inform the development of novel therapeutic interventions to prevent and treat these types of infections. Research is specifically focused on understanding the host immune response to the bacterium Staphylococcus aureus, the notorious causative agent of MRSA. AMR represents a fundamental threat to global health, the economy and society as a whole. An estimated 1.2 million people died from an antibiotic resistant bacterial infection in 20195, with Staphylococcus aureus causing the highest number of AMR attributable deaths in high income countries5. The health priority posed by S. aureus infection, urgently necessitates development of novel effective therapies and prophylactic interventions that improve clinical outcomes by providing broad spectrum protection, regardless of antimicrobial resistance patterns. Development of strategies to harness host immunity through novel host directed therapies and new vaccines would go a long way towards achieving this.

Research in the Host-Pathogen Interactions Group centres on three themes:

Delineating immune evasion strategies employed by Staphylococcus aureus to circumvent protective immunity.

S. aureus was traditionally considered an extracellular bacterium, however it is now appreciated that this bacterium can survive intracellular as an effective mechanism by which to evade host immunity. In particular our research has revealed that S.aureus is very adept at surviving inside phagocytes, the very cell types that the immune system relies of for eradication of this bacterium. To achieve this, S. aureus utilises a spectrum of virulence factors that can manipulate a variety of phagocyte effector functions. Our work has identified that S. aureus can manipulate autophagic and apoptotic pathways in neutrophils to facilitate the maintenance of its intracellular survival niche. Current work is now focused on understanding the metabolic crosstalk that occurs between the bacterium and the host to facilitate intracellular survival in phagocytes.

Understanding the cellular immune response to S. aureus infection to support vaccine and immunotherapeutic development.

Through this work we have made seminal discoveries highlighting the importance of cellular immunity in S. aureus infection that have directly informed the development of S. aureus vaccines and which have precipitated a shift from exclusive focus on antibody mediated immunity as a correlate of protection for S. arueus vaccines. More recently we have begun to unravel the importance of unconventional T-cells such as gdTcells and MAIT cells in mediating protective immunity against S. aureus infection. These studies employ both in vivo models of infection to identify mechanisms of protective cellular immunity and along with translational studies to prove relevance of these protective mechanism in S. aureus infected patient cohorts. Knowledge gained is identifying novel correlates of immunity that will facilitate the development of next generation immunogenic vaccines and novel therapeutics to advance our assault on this deadly bacterium.

Investigating the host immune response to asymptomatic S. aureus exposure

In contrast to its invasive infectious potential, S. aureus, is also an important part of the normal human microbiome. The primary reservoir for S. aureus in humans is the anterior nares, where it can colonise up to ~30% of healthy humans persistently. .Our work has expanded understanding of bacterial and host factors that facilitate S. aureus persistence within the nasal cavity, revealing that local T-cell mediated immunity is a critical host protective response enacted to promote clearance of S. aureus from this site, and demonstrating that the bacterium has evolved an arsenal of immune evasion tactics to counteract both innate and adaptive immunity to ensure its persistence within this niche. We are now interested in understanding what are the downstream consequences of this immune exposure for the host and how this asymptomatic exposure to S. aureus might influence the immune response to subsequent vaccination or infection.

Media coverage

2024 – Newstalk Anton Savage Show - Breakthrough with potentially deadly superbug MRSA
2024 – Irish Independent - MRSA superbug breakthrough by Trinity College scientists
2020 – Irish Examiner - Scientist and mum of three produces rap video to promote vaccination programme
2018 – Talk at the Science Galley 10th Birthday Celebration
2015 – Irish Examiner: MRSA vaccine breakthrough for Trinity team
2015 – Drug Discovery & Development: Immunologists Unearth Key Piece of MRSA Vaccine Puzzle
2015 – MedicalXpress: Immunologists unearth key piece of MRSA vaccine puzzle
2013 – thejournal.ie: TCD researchers discover how MRSA bacterium is carried in human nose