Regulatory CD4+CD25+ T cells play a critical role within the immune system through their ability to mediate self-tolerance. They are involved in a variety of disease settings including human autoimmune disease, transplant rejection, and graft-versus-host disease, and can enable cancer cells to evade the host immune response.

“We have produced reagents that are more specific than those used previously to label regulatory T cells and have demonstrated their utility in the study of human samples.”

FOXP3 is the best single marker of regulatory T cells and we were the first group to describe the production and characterization of specific monoclonal antibodies against the human FOXP3 protein, enabling this population to be studied at the single cell level. The involvement of regulatory T cells within so many diverse systems, along with our willingness to share reagents with members of the scientific community, are two key reasons why our paper is being highly cited.

Our paper describes the production of FOXP3 antibodies by Dr. Giovanna Roncador’s Monoclonal Antibody Unit at the CNIO in Madrid and our characterization of these reagents. In collaboration with Professor Fiona Powrie’s and Professor Enzo Cerundolo’s groups at Oxford, we further demonstrated their utility as key reagents for labeling and immunophenotyping human regulatory T cells, using a number of different experimental techniques, particularly the assessment of their frequency within the human CD4+ T-cell population using flow cytometry. These reagents are valuable tools to investigate FOXP3 function and are applicable for routine clinical use.

A population of regulatory T cells, expressing the FOXP3 marker, is important for controlling autoimmunity and the ability of the immune system to eliminate tumor cells. We have produced reagents that are more specific than those used previously to label regulatory T cells and have demonstrated their utility in the study of human samples.

I became interested in FOXP3 primarily through the study of the related FOXP1 transcription factor. One problem, as this is a competitive field, was the need to characterize our reagents as quickly as possible. We achieved this through collaboration and were greatly assisted by specific funding from the Leukemia Research Fund to develop our reagents.

As cancer is a major cause of mortality, there are social implications arising from our research. Follow-up studies have demonstrated the clinical relevance of regulatory T cell numbers as a prognostic marker predicting survival for cancer patients and also identified this population as a target for therapeutic intervention.