Immunology Graduate Group
Jim Riley, Ph.D.
Department of Pathology and Lab Medicine
Address: 556 BRB II/III
Office Phone: 215-573-6792
Lab Phone: 215-746-5505
Email: rileyj@mail.med.upenn.edu
Education:
Ph.D., Emory University
B.S., Vanderbilt University
Research Interests
Signal transduction initiated by members of the CD28 family;
Expansion and characterization of HIV specific T cells
Research Summary
Research in the Riley laboratory focuses costimulatory pathways that control human T cell activation and differentiation. One major project focuses on signal transduction pathways initiated by members of the CD28 family (CD28, ICOS, CTLA-4, PD-1 and BTLA). These receptors, despite their structural similarity, play distinct roles in modulating the immune system. No recognizable enzymatic activity has been associated with any of their cytoplasmic tails but rather these receptors are thought to recruit unique set of signal transducing molecules, which choreograph their distinct effects on T cell activation. Our approach has been to create chimeric receptors, consisting of the murine CD28 extracellular domain coupled to the cytoplasmic tails of each of the CD28 family members, introduce these constructs into primary human T cells by lentiviral transduction and perform structure function studies to determine which domains within the CD28 family members cytoplasmic tails are responsible for transducing particular signals by selectively triggering the introduced construct with mCD28 specific Ab. Currently, we are taking advantage of this high efficiency of this lentiviral transduction system to introduce siRNA cassettes that target downstream effector molecules in order how absence of these molecules alters how members of the CD28 affect T cell activation. We have also been successful using DNA microarrays as an end point of signal transduction assays. The technique of gene expression profiling by DNA microarray hybridization represents an alternative approach for studying the circuitry of signaling pathways. This technique allows systematic measurement of the expression of many thousands of discrete sequences in a single assay {Lockhart, Dong, et al. 1996 495 /id} . . Thus, one signaling pathway can be compared to another by measuring differences in both the amplitude and absolute number of gene regulations triggered . . Additionally, insights into how signaling pathways integrate can be gained by measurement of gene expression changes induced by simultaneous triggering of two pathways. Understanding how these pathways alter a T cell's response to antigen stimulation on a global basis may lead to the development of novel therapeutics for HIV and cancer.
The second major project strives to develop artificial antigen presenting cells (APCs). We have created a library of lentiviral vectors encoding costimulatory molecules, HLA alleles, cytokines and chemokines that we used to transduce a MHC deficient cell line, K562. To date, we have engineered cells to express up to eight genes, providing the platform by which to dissect the signals required to optimally activate and expand human T cell subsets.
Recent Publications
Thomas AK., Maus MV., Shalaby WS., June CH., Riley JL.: A cell-based artificial antigen-presenting cell coated with anti-CD3 and CD28 antibodies enables rapid expansion and long-term growth of CD4 T lymphocytes. Clinical Immunology 105(3): 259-72, Dec 2002.
Riley, JL., Mao, M., Kobayashi, S., Biery, M., Burchard, J., Cavet, G., Gregson, B., June, CH., and Linsley, PS. Modulation of TCR Induced Transcriptional Profiles by Ligation of CD28, ICOS and CTLA-4 Receptors. Proceedings of the National Academy of Sciences of the United States of America . 99(18) 11790-11795, Sep 2002.
Parry RV., Rumbley CA., Vandenberghe LH., June CH., Riley JL.: CD28 and inducible costimulatory protein Src homology 2 binding domains show distinct regulation of phosphatidylinositol 3-kinase, Bcl-xL, and IL-2 expression in primary human CD4 T lymphocytes. Journal of Immunology 171(1): 166-74, Jul 1 2003.
Chemnitz, JM., Parry, RV., Nichols, KE., June, CH., Riley, JL.: SHP-1 and SHP-2 Associate with PD-1's Immunoreceptor Tyrosine-Based Switch Motif upon Primary Human T cell Stimulation, but only Receptor Ligation Prevents T cell Activation. Journal of Immunology in press.
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