Modulation of T cell development by an endogenous altered peptide ligand.

T cells potentially encounter numerous endogenous peptides during selection in the thymus and in the periphery. We examined the impact of an endogenous peptide on in vivo T cell development, using a TCR transgenic mouse model based on a hemoglobin-specific T cell clone. In these mice, the transgenic beta chains paired with endogenous alpha chains. This led to a serendipitous primary reactivity to Ser69 peptide, an altered peptide ligand of the Hbd (64-76) epitope of the parent clone. Two Ser69-reactive T cell populations were identified. A smaller population of the Ser69-reactive T cells responded both to Ser69 and Hbd (64-76). A majority reacted only to Ser69, and not to Hbd(64-76); in fact, Hbd(64-76) was a specific TCR antagonist for these Ser69-only-reactive T cells. Thus, in this unique experimental system, Ser69 became an agonist, and Hbd (64-76) was an antagonist. Endogenous presentation of the antagonist ligand in the thymus selectively eliminated the high-avidity cells, while sparing low-avidity cells in the Ser69-reactive T cell repertoire. These results highlight how specificity guides developing T cells through a network of ligands and indicate that the endogenous peptide pool has a profound effect on T cell development and repertoire.

Download Full-text

Mutation of the phospholipase C-γ1–binding site of LAT affects both positive and negative thymocyte selection

Journal of Experimental Medicine ◽

10.1084/jem.20041869 ◽

2005 ◽

Vol 201 (7) ◽

pp. 1125-1134 ◽

Cited By ~ 59

Author(s):

Connie L. Sommers ◽

Jan Lee ◽

Kevin L. Steiner ◽

Jordan M. Gurson ◽

Corinne L. DePersis ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Positive Selection ◽

Phospholipase C ◽

Negative Selection ◽

T Cell Development ◽

Adaptor Protein ◽

Cell Development ◽

Autoreactive T Cells ◽

The Impact

Linker for activation of T cells (LAT) is a scaffolding adaptor protein that is critical for T cell development and function. A mutation of LAT (Y136F) that disrupts phospholipase C-γ1 activation and subsequent calcium influx causes a partial block in T cell development and leads to a severe lymphoproliferative disease in homozygous knock-in mice. One possible contribution to the fatal disease of LAT Y136F knock-in mice could be from autoreactive T cells generated in these mice because of altered thymocyte selection. To examine the impact of the LAT Y136F mutation on thymocyte positive and negative selection, we bred this mutation onto the HY T cell receptor (TCR) transgenic, recombination activating gene-2 knockout background. Female mice with this genotype showed a severe defect in positive selection, whereas male mice exhibited a phenotype resembling positive selection (i.e., development and survival of CD8hi HY TCR-specific T cells) instead of negative selection. These results support the hypothesis that in non-TCR transgenic, LAT Y136F knock-in mice, altered thymocyte selection leads to the survival and proliferation of autoreactive T cells that would otherwise be negatively selected in the thymus.

Download Full-text

Altered thymocyte and T cell development in neonatal mice with hyperoxia-induced lung injury

Journal of Perinatal Medicine ◽

10.1515/jpm-2016-0234 ◽

2018 ◽

Vol 46 (4) ◽

pp. 441-449

Author(s):

Sowmya Angusamy ◽

Tamer Mansour ◽

Mohammed Abdulmageed ◽

Rachel Han ◽

Brian C. Schutte ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Lung Injury ◽

T Cell Development ◽

Adaptive Immune System ◽

Cell Development ◽

Thymocyte Development ◽

Double Positive ◽

Neonatal Mice ◽

Single Positive

Abstract Background: The adaptive immune system of neonates is relatively underdeveloped. The thymus is an essential organ for adaptive T cell development and might be affected during the natural course of oxygen induced lung injury. The effect of prolonged hyperoxia on the thymus, thymocyte and T cell development, and its proliferation has not been studied extensively. Methods: Neonatal mice were exposed to 85% oxygen (hyperoxia) or room air (normoxia) up to 28 days. Flow cytometry using surface markers were used to assay for thymocyte development and proliferation. Results: Mice exposed to prolonged hyperoxia had evidence of lung injury associated alveolar simplification, a significantly lower mean weight, smaller thymic size, lower mean thymocyte count and higher percentage of apoptotic thymocytes. T cells subpopulation in the thymus showed a significant reduction in the count and proliferation of double positive and double negative T cells. There was a significant reduction in the count and proliferation of single positive CD4+ and CD8+ T cells. Conclusions: Prolonged hyperoxia in neonatal mice adversely affected thymic size, thymocyte count and altered the distribution of T cells sub-populations. These results are consistent with the hypothesis that prolonged hyperoxia causes defective development of T cells in the thymus.

Download Full-text

Interleukin-7 Regulates Bim Proapoptotic Activity in Peripheral T-Cell Survival

Molecular and Cellular Biology ◽

10.1128/mcb.01006-09 ◽

2009 ◽

Vol 30 (3) ◽

pp. 590-600 ◽

Cited By ~ 23

Author(s):

Wen Qing Li ◽

Tad Guszczynski ◽

Julie A. Hixon ◽

Scott K. Durum

Keyword(s):

T Cells ◽

T Cell ◽

Cell Survival ◽

T Cell Development ◽

Cell Development ◽

Effector Memory ◽

Intracellular Location ◽

Interleukin 7 ◽

Peripheral T Cells ◽

T Cell Survival

ABSTRACT Interleukin-7 (IL-7) is critical for T-cell development and peripheral T-cell homeostasis. The survival of pro-T cells and mature T cells requires IL-7. The survival function of IL-7 is accomplished partly through induction of the antiapoptotic protein Bcl-2 and inhibition of proapoptotic proteins Bax and Bad. We show here that the proapoptotic protein Bim, a BH3-only protein belonging to the Bcl-2 family, also plays a role in peripheral T-cell survival. Deletion of Bim partially protected an IL-7-dependent T-cell line and peripheral T cells, especially cells with an effector memory phenotype, from IL-7 deprivation. However, T-cell development in the thymus was not restored in IL-7−/− Rag2−/− mice reconstituted with Bim−/− bone marrow. IL-7 withdrawal altered neither the intracellular location of Bim, which was constitutively mitochondrial, nor its association with Bcl-2; however, a reduction in its association with the prosurvival protein Mcl-1 was observed. IL-7 withdrawal did not increase Bim mRNA or protein expression but did induce changes in the isoelectric point of BimEL and its reactivity with an antiphosphoserine antibody. Our findings suggest that the maintenance of peripheral T cells by IL-7 occurs partly through inhibition of Bim activity at the posttranslational level.

Download Full-text

Conditional Knockout Mice Reveal Distinct Functions for the Global Transcriptional Coactivators CBP and p300 in T-Cell Development

Molecular and Cellular Biology ◽

10.1128/mcb.26.3.789-809.2006 ◽

2006 ◽

Vol 26 (3) ◽

pp. 789-809 ◽

Cited By ~ 136

Author(s):

Lawryn H. Kasper ◽

Tomofusa Fukuyama ◽

Michelle A. Biesen ◽

Fayçal Boussouar ◽

Caili Tong ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

T Cell ◽

T Cell Development ◽

Cell Development ◽

Conditional Knockout ◽

Specific Cell ◽

Creb Binding Protein ◽

Thymocyte Development ◽

Transcriptional Coactivators

ABSTRACT The global transcriptional coactivators CREB-binding protein (CBP) and the closely related p300 interact with over 312 proteins, making them among the most heavily connected hubs in the known mammalian protein-protein interactome. It is largely uncertain, however, if these interactions are important in specific cell lineages of adult animals, as homozygous null mutations in either CBP or p300 result in early embryonic lethality in mice. Here we describe a Cre/LoxP conditional p300 null allele (p300 flox ) that allows for the temporal and tissue-specific inactivation of p300. We used mice carrying p300 flox and a CBP conditional knockout allele (CBP flox ) in conjunction with an Lck-Cre transgene to delete CBP and p300 starting at the CD4− CD8− double-negative thymocyte stage of T-cell development. Loss of either p300 or CBP led to a decrease in CD4+ CD8+ double-positive thymocytes, but an increase in the percentage of CD8+ single-positive thymocytes seen in CBP mutant mice was not observed in p300 mutants. T cells completely lacking both CBP and p300 did not develop normally and were nonexistent or very rare in the periphery, however. T cells lacking CBP or p300 had reduced tumor necrosis factor alpha gene expression in response to phorbol ester and ionophore, while signal-responsive gene expression in CBP- or p300-deficient macrophages was largely intact. Thus, CBP and p300 each supply a surprising degree of redundant coactivation capacity in T cells and macrophages, although each gene has also unique properties in thymocyte development.

Download Full-text

Placing Ion Channels into a Signaling Network of T Cells: From Maturing Thymocytes to Healthy T Lymphocytes or Leukemic T Lymphoblasts

BioMed Research International ◽

10.1155/2015/750203 ◽

2015 ◽

Vol 2015 ◽

pp. 1-32 ◽

Cited By ~ 5

Author(s):

Oxana Dobrovinskaya ◽

Iván Delgado-Enciso ◽

Laura Johanna Quintero-Castro ◽

Carlos Best-Aguilera ◽

Rocío Monserrat Rojas-Sotelo ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Ion Channels ◽

Cell Cycle Progression ◽

T Cell Development ◽

Cell Development ◽

Signaling Network ◽

Self Renewal ◽

And Migration ◽

Regulation Of Cell Cycle

T leukemogenesis is a multistep process, where the genetic errors during T cell maturation cause the healthy progenitor to convert into the leukemic precursor that lost its ability to differentiate but possesses high potential for proliferation, self-renewal, and migration. A new misdirecting “leukemogenic” signaling network appears, composed by three types of participants which are encoded by (1) genes implicated in determined stages of T cell development but deregulated by translocations or mutations, (2) genes which normally do not participate in T cell development but are upregulated, and (3) nondifferentially expressed genes which become highly interconnected with genes expressed differentially. It appears that each of three groups may contain genes coding ion channels. In T cells, ion channels are implicated in regulation of cell cycle progression, differentiation, activation, migration, and cell death. In the present review we are going to reveal a relationship between different genetic defects, which drive the T cell neoplasias, with calcium signaling and ion channels. We suggest that changes in regulation of various ion channels in different types of the T leukemias may provide the intracellular ion microenvironment favorable to maintain self-renewal capacity, arrest differentiation, induce proliferation, and enhance motility.

Download Full-text

Abrogation of CD40–CD154 Signaling Impedes the Homeostasis of Thymic Resident Regulatory T Cells by Altering the Levels of IL-2, but Does Not Affect Regulatory T Cell Development

The Journal of Immunology ◽

10.4049/jimmunol.1200588 ◽

2012 ◽

Vol 189 (4) ◽

pp. 1717-1725 ◽

Cited By ~ 17

Author(s):

Steven M. Cuss ◽

E. Allison Green

Keyword(s):

T Cells ◽

T Cell ◽

Regulatory T Cells ◽

Regulatory T Cell ◽

T Cell Development ◽

Cell Development

Download Full-text

Insights into the ontogeny and activation of T cells

Clinical Chemistry ◽

10.1093/clinchem/40.11.2128 ◽

1994 ◽

Vol 40 (11) ◽

pp. 2128-2131 ◽

Cited By ~ 5

Author(s):

T W Mak

Keyword(s):

T Cells ◽

T Cell ◽

T Lymphocytes ◽

Cell Surface ◽

Immune Responses ◽

Tyrosine Phosphatase ◽

T Cell Development ◽

Cell Development ◽

Mutant Mice ◽

Target Cells

Abstract T lymphocytes recognize antigen peptides and major histocompatibility complex products through their T-cell antigen receptors (TcR), consisting of alpha and beta chains. The interaction between T cells and their target cells or antigen-presenting cells is also assisted by a series of other cell-surface polypeptides, most notably CD4 and CD8, which are selectively expressed on mature helper/inducer and killer/suppressor T cells, respectively. Upon engagement of their ligands, a series of signals is transduced intracytoplasmically via some of these molecules and their associated proteins. Perhaps the most important enzyme in this signal transduction process is the lymphocyte-specific tyrosine kinase lck. Another important component is the cell-surface tyrosine phosphatase CD45. This molecule is alternatively spliced and the different isoforms are expressed on the various hematopoietic and lymphopoietic cells. Signaling through the TcR-CD4 D8-lck-CD45 complex is thought to be insufficient to activate T lymphocytes. A costimulatory signal is believed to be essential, and many investigators have suggested that CD28, a ligand for B7/BB1, is such a signal. Immune responses are also controlled by a number of cytokines and soluble factors. Signaling through the tumor necrosis factor receptor p55 is required for clearance of intracellular pathogens. Transcriptional factors involved in controlling interferon production are also important in T-cell development and immune responses. In an attempt to gain a better understanding of the roles of these molecules in T-lymphocyte functions and ontogeny, we generated a series of mutant mice with disruptions in the genes coding for these molecules. We are analyzing the mutant mice to evaluate the importance of these genes in T-cell development.

Download Full-text

Inactivation of c-Cbl Reverses Neonatal Lethality and T Cell Developmental Arrest of SLP-76–deficient Mice

Journal of Experimental Medicine ◽

10.1084/jem.20040262 ◽

2004 ◽

Vol 200 (1) ◽

pp. 25-34 ◽

Cited By ~ 24

Author(s):

Y. Jeffrey Chiang ◽

Connie L. Sommers ◽

Martha S. Jordan ◽

Hua Gu ◽

Lawrence E. Samelson ◽

...

Keyword(s):

Signal Transduction ◽

T Cells ◽

T Cell ◽

T Cell Development ◽

Adaptor Protein ◽

Premature Death ◽

Cell Receptor ◽

Cell Development ◽

Neonatal Lethality ◽

Deficient Mice

c-Cbl is an adaptor protein that negatively regulates signal transduction events involved in thymic-positive selection. To further characterize the function of c-Cbl in T cell development, we analyzed the effect of c-Cbl inactivation in mice deficient in the scaffolding molecule SLP-76. SLP-76–deficient mice show a high frequency of neonatal lethality; and in surviving mice, T cell development is blocked at the DN3 stage. Inactivation of c-cbl completely reversed the neonatal lethality seen in SLP-76–deficient mice and partially reversed the T cell development arrest in these mice. SLP-76−/− Cbl−/− mice exhibited marked expansion of polarized T helper type (Th)1 and Th2 cell peripheral CD4+ T cells, lymphoid infiltrates of parenchymal organs, and premature death. This rescue of T cell development is T cell receptor dependent because it does not occur in recombination activating gene 2−/− SLP-76−/− Cbl−/− triple knockout mice. Analysis of the signal transduction properties of SLP-76−/− Cbl−/− T cells reveals a novel SLP-76– and linker for activation of T cells–independent pathway of extracellular signal–regulated kinase activation, which is normally down-regulated by c-Cbl.

Download Full-text