Microbial ligand-independent regulation of lymphopoiesis by NOD1.

Aberrant differentiation of progenitor cells in the hematopoietic system is known to severely impact host immune responsiveness. Here we demonstrate that NOD1, a cytosolic innate sensor of bacterial peptidoglycan, also functions in murine hematopoietic cells as a major regulator of both the generation and differentiation of lymphoid progenitors as well as peripheral T lymphocyte homeostasis. We further show that NOD1 mediates these functions by facilitating STAT5 signaling downstream of hematopoietic cytokines.

Increased Activity of a NK-Specific CAR-NK Framework Targeting CD3 and CD5 for T-Cell Leukemias.

NK effector cells expressing a CAR construct may be used to target T-lineage markers. In this work, we compared the activity of a NK-specific CAR-NK and a CAR-T framework when expressed on NK effector cells to target CD3 and CD5 in T-cell malignancies. Our results show that CD3-CAR-T is more active than CD5-CAR-T to eliminate malignant T cells in vitro, however, CD3-CAR-T were less efficient to eliminate tumor cells in vivo, while CD5-CAR-T had antitumor activity in a diffuse xenograft model.

PD-1 Inhibitory Receptor Downregulates Asparaginyl Endopeptidase and Maintains Foxp3 Transcription Factor Stability in Induced Regulatory T Cells.

CD4 T cell differentiation into multiple T helper (Th) cell lineages is critical for optimal adaptive immune responses. This report identifies an intrinsic mechanism by which programmed death-1 receptor (PD-1) signaling imparted regulatory phenotype to Foxp3 Th1 cells (denoted as TbetiTreg cells) and inducible regulatory T (iTreg) cells. TbetiTreg cells prevented inflammation in murine models of experimental colitis and experimental graft versus host disease (GvHD).

Generation of Tumor Antigen-Specific iPSC-Derived Thymic Emigrants Using a 3D Thymic Culture System.

Induced pluripotent stem cell (iPSC)-derived T cells may provide future therapies for cancer patients, but those generated by current methods, such as the OP9/DLL1 system, have shown abnormalities that pose major barriers for clinical translation. Our data indicate that these iPSC-derived CD8 single-positive T cells are more like CD4CD8 double-positive T cells than mature naive T cells because they display phenotypic markers of developmental arrest and an innate-like phenotype after stimulation. We developed a 3D thymic culture system to avoid these aberrant developmental fates, generating a homogeneous subset of CD8αβ antigen-specific T cells, designated iPSC-derived thymic emigrants (iTEs).

In vivo kinetics and nonradioactive imaging of rapidly proliferating cells in graft-versus-host disease.

Hematopoietic stem cell transplantation (HSCT) offers a cure for cancers that are refractory to chemotherapy and radiation. Most HSCT recipients develop chronic graft-versus-host disease (cGVHD), a systemic alloimmune attack on host organs. Diagnosis is based on clinical signs and symptoms, as biopsies are risky.

Distinct IL-7 signaling in recent thymic emigrants versus mature naïve T cells controls T-cell homeostasis.

IL-7 is essential for T-cell survival but its availability is limited in vivo. Consequently, all peripheral T cells, including recent thymic emigrants (RTEs) are constantly competing for IL-7 to survive. RTEs are required to replenish TCR diversity and rejuvenate the peripheral T-cell pool.

Analysis of Cell Proliferation and Homeostasis Using EdU Labeling.

Determination of cellular proliferation and population turnover is an important tool for research on lymphoid cell function. Historically this has been done using radiolabeled nucleotides or nucleoside analogs, such as BrdU (5-bromo-2-deoxyuridine), that are incorporated into nascent DNA during S-phase. Recently, a new procedure was developed to label nascent DNA using EdU (5-Ethynyl-2-deoxyuridine).

Bone Marrow and Fetal Liver Radiation Chimeras.

Radiation chimeras are prepared by subjecting recipient mice to sublethal or lethal dose of irradiation and injecting them with hematopoietic stem cells (HSC) from untreated donor mice. HSC can be obtained from bone marrow or fetal liver. This technique is a powerful tool when coupled with gene targeting strategies to investigate function of HSCs, thymocyte development, and T cell function.

High levels of IL-7 cause dysregulation of thymocyte development.

IL-7 signaling is required for thymocyte development and its loss has a severe deleterious effect on thymus function. Thymocyte-stromal cell interactions and other mechanisms tightly regulate IL-7 expression. We show that disruption of that regulation by over-expression of IL-7 inhibits T-cell development and promotes extensive B-cell lymphopoiesis in the thymus.

Quantitative analysis of T cell receptor diversity in clinical samples of human peripheral blood.

The analysis of T cell receptor diversity provides a clinically relevant and sensitive marker of repertoire loss, gain, or skewing. Spectratyping is a broadly utilized technique to measure global TCR diversity by the analysis of the lengths of CDR3 fragments in each Vβ family. However the common use of large numbers of T cells to obtain a global view of TCR Vβ CDR3 diversity has restricted spectratyping analyses when limited T-cell numbers are available in clinical setting, such as following transplant regimens.

Tbata modulates thymic stromal cell proliferation and thymus function.

Niche availability provided by stromal cells is critical to thymus function. Thymi with diminished function contain fewer stromal cells, whereas thymi with robust function contain proliferating stromal cell populations. Here, we show that the thymus, brain, and testes-associated gene (Tbata; also known as SPATIAL) regulates thymic epithelial cell (TEC) proliferation and thymus size.

Rapamycin generates anti-apoptotic human Th1/Tc1 cells via autophagy for induction of xenogeneic GVHD.

Murine T cells exposed to rapamycin maintain flexibility towards Th1/Tc1 differentiation, thereby indicating that rapamycin promotion of regulatory T cells (Tregs) is conditional. The degree to which rapamycin might inhibit human Th1/Tc1 differentiation has not been evaluated. In the presence of rapamycin, T cell costimulation and polarization with IL-12 or IFN-α permitted human CD4+ and CD8+ T cell differentiation towards a Th1/Tc1 phenotype; activation of STAT1 and STAT4 pathways essential for Th1/Tc1 polarity was preserved during mTOR blockade but instead abrogated by PI3 kinase inhibition.

Aging, immunity and cancer.

Immunosenescence, the progressive decline in immune function that develops with age, results from cumulative alterations in critical B- and T-cell subpopulations. Decreases in circulating memory B cells and in germinal center formation are evident in the elderly, possibly due to diminished follicular dendritic-cell function. T-cell dysfunction is associated with reduced thymic generation of naïve T cells, virus-induced expansion of terminal effectors and increased levels of memory cells producing type I and II cytokines.