Our Science – Gildersleeve Website

Jeffrey C. Gildersleeve, Ph.D.

Chemical Biology Laboratory Head, Chemical Biology Section Investigator Building 376, Room 109 National Cancer Institute Frederick, MD 21702-1201 Phone:   301-846-5699 Fax:   301-846-6033 E-Mail:   gildersleevej@ncifcrf.gov

Biography

Jeff Gildersleeve began his professional training in sunny southern California at the University of California at San Diego. He graduated in 1993 with a B.S. degree in biology and then moved to New Jersey to pursue a Ph.D. in organic chemistry at Princeton University. Under the guidance of Professor Dan Kahne, his graduate training focused on mechanistic organic chemistry, carbohydrate chemistry, and chemical biology. After completing his Ph.D., he headed back to southern California where he worked with Professor Peter Schultz at The Scripps Research Institute. His postdoctoral work focused on directed evolution of protein catalysts and the development of high-throughput screens for protein catalysts such as catalytic antibodies. In the summer of 2003, he completed one more 3000 mile shot across the heartland and began his current position as a tenure-track Principal Investigator in the Chemical Biology Laboratory (previously, the Laboratory of Medicinal Chemistry). His research focuses on the development of carbohydrate microarray technology and its application to cancer vaccine and biomarker research.

Research

- Development of carbohydrate microarray technology
- Application of carbohydrate microarrays to vaccine and biomarker research
- Synthesis of carbohydrate tumor antigens and glycans

Carbohydrate Microarray Technology
Carbohydrate-protein interactions play a critical role in a wide range of biological processes such as inflammation and metastasis, and carbohydrate-binding proteins such as lectins and antibodies can be used as diagnostic and therapeutic agents. Traditional methods for studying carbohydrate recognition are slow and/or require large amounts of material. As a result, it has been difficult to determine if a particular protein is a carbohydrate-binding protein, to identify carbohydrate ligands to modulate biological processes, and to develop carbohydrate-binding antibodies as research and diagnostic tools. Over the last few years, our group and others have been developing carbohydrate microarray technology for the high-throughput analysis of carbohydrate-macromolecule interactions. Carbohydrate microarrays, or glycan arrays, are analogous to DNA and protein arrays but contain many different carbohydrate structures spotted on a microscope slide in a spatially-defined arrangement. The miniaturized format permits analysis of many potential interactions while using only tiny amounts of precious materials. Since most carbohydrate-protein interactions require multivalent binding to achieve a high functional affinity, presentation on the array surface is a key design feature for carbohydrate microarrays. Other groups print monovalent glycans and then utilize the array surface as a multivalent scaffold. To construct our arrays, we attach carbohydrates to a carrier protein such as bovine serum albumin (BSA) and then print these neoglycoconjugates, along with natural glycoproteins, on epoxide-coated glass microscope slides using a robotic microarrayer. With this approach, the carrier protein serves both as a linker for immobilization and as a multivalent scaffold. The advantage of this approach is that the neoglycoproteins can be used as multivalent inhibitors, reagents, and immunogens without having to identify an alternative multivalent scaffold that mimics the array surface. In addition, this approach provides unique strategies for varying carbohydrate presentation. As of February 2009, our array has 190 array components.

One of the major challenges for development of a glycan array is obtaining a diverse set of carbohydrates for the array. Our group relies heavily on synthetic organic chemistry to acquire homogeneous, structurally-defined oligosaccharides for the array. In support of this, we also develop better synthetic methods for obtaining many oligosaccharides.

Application of Carbohydrate Microarray Technology to Cancer Research
Cancer cells undergo dramatic changes in carbohydrate expression during the onset and progression of disease. Many of these alterations are found on the cell surface or on secreted glycoproteins making them appealing molecular targets for the development of diagnostics and therapeutic agents. As a result, there are major efforts to develop carbohydrate binding monoclonal antibodies and/or lectins as research tools and diagnostic reagents. In addition, many cancer vaccines currently in clinical trials generate immune responses to glycans, glycoproteins, and or glycolipids. We are applying carbohydrate microarray technology in several areas:

1. Evaluation of antibody and lectin specificity
We have used the array to evaluate the specificity of over 60 different antibodies and lectins. These reagents have been used for many years to detect expression of carbohydrate antigens on cells, glycoproteins, and biopsy samples. We have found that many of the reagents thought to be specific for a single carbohydrate antigen can cross-react with other carbohydrate structures, suggesting that much of the information in the literature on carbohydrate expression is inaccurate.

2. Profiling serum antibodies
We are using the array to profile the repertoire of carbohydrate-binding antibodies in serum. Serum antibody profiles can be used to identify new biomarkers, discover new carbohydrate antigens, and evaluate responses to cancer vaccines.


Collaborations and Carbohydrate Microarray Screening
We are frequently asked to screen lectins, antibodies, and other entities on our array. Although we are not a screening core facility, we are happy to help out in many cases. Please contact Jeff Gildersleeve for more details.

This page was last updated on 12/1/2009.