Oral Presentation Australasian Cytometry Society 44th Annual Conference and Workshop

CD4 and CD8 T cells express CD11b in the blood of colorectal cancer patients. (24551)

Jessica E Harte 1 , Fran Munro 2 , Helen M McGuire 3 4 5 , Roslyn A Kemp 1
  1. Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand
  2. Department of Surgical Sciences , University of Otago, Dunedin, Otago, New Zealand
  3. Discipline of Pathology, School of Medical Sciences, Faculty of Medicine and Health , University of Otago, Sydney , NSW, Australia
  4. Ramaciotti Facility for Human Systems Biology , University of Sydney, Sydney , NSW, Australia
  5. Charles Perkins Centre, University of Sydney, Sydney , NSW, Australia

Effector T cells play a pivotal role in anti-tumour immunity. Tumour infiltrating CD8+ T cells are associated with a positive patient prognosis. Regulatory T cells (Tregs) can be detrimental to this response by inhibiting anti-tumour immunity. T cell migration is essential to the anti-tumour immune response and depends on the expression of adhesion molecules such as CD11b and chemokine receptors. CD11b is expressed on granulocytes, macrophages, dendritic cells, NK cells, and a small subset of activated B and T cells. We have identified two populations of CD11b expressing T cells enriched in the blood of colorectal cancer patients compared to non-tumour bowel and peripheral blood. We propose that expression of CD11b is expressed on newly activated tumour specific T cells and is involved in T cell migration into the tumour microenvironment.

 

Using mass cytometry, we have shown an enrichment of CD11b+ CD8+ and CD11b+ CD4+ T cells in the blood of CRC patients compared to patient-matched tumour and non-tumour bowel (n=27 SAM analysis) and a higher percentage of CD11b+ T cells in the blood of CRC patients compared with healthy donors (n= 6). We have used an in vitro T cell based assay to identify tumour specific responses of CD11b+ T cells. In addition, we have developed an in vitro transwell migration system to study the migratory properties of CD11b+ expression on T cells and the effect it has on migration into the tumour microenvironment. 

 

These data will provide insights as to whether CD11b expressing T cells are tumour specific and whether expression of CD11b is essential for T cell migration into the tumour microenvironment.