Research Overview

The Greenberg lab continues to focus on both basic immunology and cancer immunobiology, and on the development and assessment of adoptive therapies with antigen-specific T cells targeting human malignancies and chronic infections.

The team is expert in identifying and validating candidate tumor antigen targets. They have made seminal advances in methods that are now widely employed for the identification and cloning of antigen-specific T cell receptors (TCRs), including high affinity TCRs, and for the rapid expansion of selected T cells in vitro. The Greenberg team is testing various other genetic engineering and cell production methods in preclinical models and moving toward new treatments, using naturally isolated or genetically-engineered T cells to effectively target cancer.

Expanding efforts include preclinical work supporting clinical trials planned for patients with ovarian and pancreatic cancers. Clinical trials are already underway for patients with small cell lung cancer, malignant melanoma and acute leukemia. In melanoma, patient (autologous) T cell clones reactive with tumor proteins are being infused into patients. Cellular and molecular techniques are being used to monitor these cells following infusion, in order to define potential obstacles to immune elimination of advanced disease.

Murine splenocytes were transduced to express wildtype-affinity WT1-specific TCR (3D-wt) or one of two CD8-independent enhanced affinity variants of 3D-wt: 3D-NYH (intermediate affinity), and 3D-PYY (highest affinity)
Murine splenocytes were transduced to express wildtype-affinity WT1-specific TCR (3D-wt) or one of two CD8-independent enhanced affinity variants of 3D-wt: 3D-NYH (intermediate affinity), and 3D-PYY (highest affinity). While peripheral T cells expressing the highest affinity TCR displayed enhanced functional avidity, retrogenic T cells (subjected to thymic selection) expressing the same high affinity TCR exhibited a functional avidity that was substantially lower than T cells expressing the lower affinity TCRs. From Immunol Rev. 2014 Jan; 257(1): 145–164. IM Stromnes, TM Schmitt, AG Chapuis, SR Hingorani, and PD Greenberg.
Overview of TCR gene therapy
Overview of TCR gene therapy. PBMCs= Peripheral blood mononuclear cells From Schmitt TM, Ragnarsson GB, Greenberg PD. Hum Gene Ther 20(11):1240-8, 2009

Small Cell Lung Cancer Trials

The Greenberg group is part of an AACR-funded multicenter “Dream Team” that is performing a trial for patients with non-small cell lung cancer. This trial is testing autologous CD8+ T cells, derived from either naïve or central memory T cell precursors, transduced to express a high affinity WT1-specific TCR developed in the Greenberg lab. Patient specimens will be monitored for upregulation of the PD-1 protein on transferred T cells and its PD-L1ligand on tumors to determine if treatment with therapeutic antibodies that block these “immune checkpoint” molecules should be pursued in a follow-up trial.

Dr. Greenberg and his lab are also working to identify epitopes in WT1 and other antigens that are commonly found on AML cells and restricted to Class I MHC alleles beyond HLA-A2, so that TCRs can be isolated and high avidity CD8+ T cells generated to treat a much broader range of patients.

Other studies are aimed at defining the cell-intrinsic regulatory mechanism(s) associated with the establishment and maintenance of immune self-tolerance. Underlying mechanism(s) will be determined and strategies developed by which tolerance imprinting and epigenetic memory can be erased to achieve permanent T cell re-programming. New strategies are also being tested to therapeutically modulate activation of immune natural killer (NK) cells that might also be useful for treating cancers.