Rossjohn Laboratory

Understanding immune function and dysfunction.

postdoc
Dr. Martin Davey
Senior ResearchFellow

Our group is investigating the role of an “unconventional” group of human T lymphocytes in immunity. The human immune system is a highly specialised network of cells, organs, receptors and soluble factors that protects the host from infection and cancer, while promoting homeostasis of the tissues. The immune system uses T lymphocytes to generate memory responses to numerous challenges throughout life. Three lineages of lymphocytes have co-evolved over the last 550 million years: B cells, ɑβ T cells and γδ T cells.

While much is known about the contribution “conventional” ɑβ T cells, unconventional T cells – including γδ T cells and MAIT cells (mucosa-associated invariant T cells) – remain poorly understood and their exact role in immunity is unclear.

Human unconventional T cells represent >20% of all T cells in the periphery and are frequently implicated in anti-bacterial, anti-viral and anti-parasitic immunity. Yet, the mechanisms that this group of immune cells employs to communicate and control these states of infection is unclear.

Our research uses use cutting-edge immunological techniques on human samples from bacterial (tuberculosis), viral (cytomegalovirus) and parasite (malaria) infected patients to unravel the immunobiology of human γδ T cells and MAIT cells.

Research Projects

1. The role of the γδ T cell receptor (TCR) in microbial infection.

2. Maintenance of tissue homeostasis by unconventional T cells.

3. Anti-microbial immune responses of unconventional T cells.

Click for full listing of publications.

Figure Legend

Human gd T cell lineages. We have provided significant insight into the immunobiology of human gd T cells.  Each gd T cell population can be divided based on their Vd chain usage. Each subset is displayed alongside a set of cell surface markers that define them in the steady state. Vg9/Vd2+ and Vd1+ gd T cells undergo postnatal clonal selection in the periphery from a naïve gd T cell pool. Vg9+/Vd2+ T cells are established in the perinatal period and are rapidly matured after birth, resulting in a uniform responsiveness to a bacterial metabolite (HMB-PP). Non-Vd1 or Vd2 T cells, express a Vd3-8 TCR chain pairing and a rare fraction in the peripheral blood but are enriched in the tissues, such as the liver. We use this unique knowledge to perform cutting edge experiments, in samples from patients who have been infected by some of the world’s most challenging diseases, to inform future vaccination strategies to better protect us.