Philip R. Streeter, Ph.D.

Dept. of Medicine
Center for Hematologic Malignancies

Biography

Dr. Philip Streeter received his B.S. from the University of California-Davis in 1977. He attended graduate school at Kansas State University, receiving an M.S. in Laboratory Medicine in 1980 and a Ph.D. in Microbiology, with a focus on tumor immunobiology in 1985. After completing his Ph.D., Dr. Streeter studies as a Postdoctoral Fellow in the Department of Pathology at Stanford University.

In 1989 Dr. Streeter joined the biotechnology company SyStemix Inc., Palo Alto, CA., as a scientist. He moved to St. Louis, MO. in 1992 to work at Searle/Monsanto, now Pfizer, where he led research efforts in the engineering of hematopoietic cytokines, the development of tumor vaccines, and development of selective inhibitors of autoimmune disease.

Dr. Streeter joined Oregon Health & Science University as an Assistant Professor in the Department of Medicine in 2000. He is a member of the OHSU Center for Hematologic Malignancies and the Oregon Stem Cell Center. In 2003 he became Laboratory Director of the OHSU Hematopoietic Cell Processing Laboratory, and he is currently Director of the Flow Cytometry and Monoclonal Antibody Core Laboratories in the Oregon Stem Cell Center.

Research Overview

The long-term goal of my research is to further enable the engineering of diverse tissues. As a model system for this goal, I have focused on the hematopoietic compartment, working in the areas of hematopoietic stem cell mobilization and engraftment, anti-tumor immune responses associated with allogeneic hematopoietic stem cell transplantation, and the adverse immune consequences associated with these transplants.

A variety of barriers limit the application or use of hematopoietic stem cells in the setting of transplantation. These include the inability to isolate sufficient numbers of stem cells and disease-treatment associated damage to stem cells or other cells required for stem cell survival. These limitations can prevent engraftment or the long-term survival of stem cells following transplantation, with this outcome leading to hematopoietic failure in transplant recipients. Thus, to make hematopoietic stem cell transplant therapy more readily available to potential recipients, we have used animal models to investigated strategies to augment hematopoietic stem cell isolation, to protect hematopoietic cells from the lethal effects of radiotherapy, and to provide transplant recipients with supporting cells intended to augment survival of hematopoietic stem cells.

Graft versus host disease (GVHD) occurs as an adverse consequence in recipients of allogeneic stem cell transplants. This disease is mediated by T cells from the stem cell donor reacting against the cells of the host. We are currently elucidating the roles of novel regulatory T cells involved in the disease, and are developing prophylactic and therapeutic strategies designed to selectively eliminate disease-promoting cells and thus control GVHD progression.

Allogeneic hematopoietic stem cell transplants are frequently curative in patients with hematologic malignancies. However, the curative potential of these transplants requires that donor T cells target and eliminate malignant cells. We are currently developing cell-based vaccines using dendritic-like cells for use in patients with leukemia. We anticipate that these vaccines will selectively amplify tumor specific immune responses and thereby augment the curative potential of allogeneic stem cell transplants.

Selected References

Streeter PR, Zhang X, Tittle TV, Schon CN, Weinberg AD, and Maziarz RT. CD25 expression distinguishes functionally distinct alloreactive CD4 CD134 (OX40) T-cell subsets in acute graft-versus-host disease. Biol Blood Marrow Transplant 10: 298-309 2004.

Streeter PR, Dudley LZ, and Fleming WH. Activation of the G-CSF and Flt-3 receptors protects hematopoietic stem cells from lethal irradiation. Exp Hematol 31: 1119-25 2003.

Fleming WH, Mulcahy JM, McKearn JP, and Streeter PR. Progenipoietin-1: a multifunctional agonist of the granulocyte colony-stimulating factor receptor and fetal liver tyrosine kinase-3 is a potent mobilizer of hematopoietic stem cells. Exp Hematol 29: 943-51 2001.

Ishioka GY, Fikes J, Qin M, Gianfrani C, Chesnut RW, Kahn LE, Streeter PR, Woulfe SL, Sette A. Dendritic cells generated in vivo by a chimeric hematopoietic growth factor, progenipoietin-4, demonstrate potent immunological function. Vaccine 19:3710-9 2001.

Streeter PR, Minster NI, Kahn LE, Hood WF, Vickery LE, Thurman TL, Monahan JB, Welply JK, McKearn JP, Woulfe SL. Progenipoietins: biological characterization of a family of dual agonists of fetal liver tyrosine kinase-3 and the granulocyte colony-stimulating factor receptor. Exp Hematol 29: 41-50 2001.

A more complete listing of publications by Dr. Streeter is available from the National Library of Medicine. PubMed