BD Biosciences seminar: Sialyl Lewis x (CD15s) identifies highly differentiated and most suppressive FoxP3high regulatory T cells in humans

Robert Balderas, Vice President of Market Development, BD Biosciences.

CD4+ regulatory T (Treg) cells expressing CD25 and the transcription factor FoxP3 are indispensable for immunological self-tolerance and homeostasis. FoxP3+CD25+CD4+ T cells in humans are, however, heterogeneous in function and differentiation status, including suppressive or non-suppressive cells as well as resting or activated Treg cells. Using a multiparallel CD marker screening technology, we have searched for cell surface markers specific for suppression-competent Treg cells by using a panel of currently available monoclonal antibodies reactive with human T cells. We found that CD15s (sialyl Lewis x) was highly specific for activated, terminally differentiated and most suppressive FoxP3high effector Treg (eTreg) cells and able to differentiate them in various clinical settings from non-suppressive FoxP3+ T cells secreting inflammatory cytokines. For example, CD15s+FoxP3+ eTreg cells were increased in sarcoidosis while it was non-suppressive CD15s-FoxP3+ T cells that were expanded in lupus flares. FoxP3+ cells induced from conventional CD4+ T cells by TCR stimulation hardly expressed CD15s. CD15s+CD4+ T cell depletion was sufficient to evoke and enhance in vitro immune responses against tumour or viral antigens. Collectively, we have identified CD15s as a biomarker instrumental in both phenotypic and functional analysis of FoxP3+CD4+ T cell subpopulations in health and disease. It allows specific targeting of eTreg cells, rather than whole FoxP3+CD4+ T cells, in controlling immune responses.
Robert Balderas has more than 35 years of leadership experience in both academia and the biotechnology industry. As a corporate scientist, site manager and marketing professional in the field of biotechnology, he has contributed to the growth of both Pharmingen and BD Biosciences.

Robert has championed multiple key successful product launches during his tenure at Pharmingen and BD Biosciences. His experience in academic medicine accompanied by his strategic approaches as the VP of Research and Development are reflected in increased efficiencies within the clinical and research product development programs, where he oversees the development of more than 4,000 reagents.

Robert Balderas worked at The Scripps Research Institute in the labs of Frank Dixon and Argyrios Theofilopoulos for 18 years, where he focused his research in the field of autoimmunity. Today, as VP of Market Development, Robert is focused on driving market adoption of new products and technologies into the life sciences community and is a core domain leader for the flow cytometry platform.

Robert has an MBA from the University of San Diego (UCSD). Additionally, Robert serves on the editorial board of Clinical Proteomics and has led two industrial/academic initiatives with Canadian Network for Visual Analytics (CANVAC) and the National Cancer Institute (NCI). He is a member of the UCSD Industrial Liaison Program, the Deans Council for the UCSD School of Biological Sciences, a board member of the Human Leukocyte Differentiation Antigens (HLDA), and leads our BD Biosciences Technology Leadership Development Program (TLDP) recruiting team. He has shared in the publishing of over 80 scientific journal articles.

Date & time

9.30–10.30am 19 October 2015


Seminar Room 1, The John Curtin School of Medical Research, 131 Garran Road, Acton


 Harpreet Vohra
 +61 2 6125 3694

Updated:  15 August 2018/Responsible Officer:  Director, JCSMR/Page Contact:  Web Manager