Pathways of T cell pathology in models of chronic intestinal inflammation.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
C Terhorst
Publications and source records attributed to C Terhorst.
NK cell-deficient mice develop a Th1-like response but fail to mount an efficient antigen-specific IgG2a antibody response.
NK cells have been shown to play a role in the modulation of B cell differentiation and Ab production. Using a novel murine model of NK cell deficiency, we analyzed the in vivo role of NK cells in the regulation of Ag-specific Ab production. After immunization with OVA or keyhole limpet hemocyanin in CFA, NK cell-deficient (NK-T+) mice developed an efficient Th1 response and produced significant levels of IFN-gamma but displayed markedly reduced or absent Ag-specific IgG2a production. There were no differences in the levels of Ag-specific IgG, IgG1, and IgG2b between NK-T+ and NK+T+ mice. Furthermore, NK cell-reconstituted, NK+T+ (tgepsilon26Y) mice produced significant amounts of Ag-specific IgG2a after immunization with OVA. These results indicate that NK cells are involved in the induction of Ag-specific IgG2a production in vivo. Moreover, they also demonstrate that the lack of Ag-specific IgG2a Ab production in NK-T+ mice is not associated with the impaired Th1 response and IFN-gamma production.
Animals↗
The CD3-gamma delta epsilon transducing module mediates CD38-induced protein-tyrosine kinase and mitogen-activated protein kinase activation in Jurkat T cells.
We have examined the ability of the CD3-gamma delta epsilon and CD3-zeta signaling modules of the T cell receptor (TCR) to couple CD38 to intracellular signaling pathways. The results demonstrated that in TCR+ T cells that express the whole set of CD3 subunits CD38 ligation led to complete tyrosine phosphorylation of both CD3-zeta and CD3-epsilon polypeptide chains. In contrast, in TCR+ cells with a defective CD3-zeta association CD38 engagement caused tyrosine phosphorylation of CD3-epsilon but not of CD3-zeta. Despite these differences, in both cell types CD38 ligation resulted in protein-tyrosine kinase and mitogen-activated protein kinase activation. However, in cells expressing chimerical CD25-zeta or CD25-epsilon receptors or in a TCR-beta- Jurkat T cell line, CD38 ligation did not result in tyrosine phosphorylation of the chimeric receptors, or CD3 subunits, or protein-tyrosine kinase or mitogen-activated protein kinase activation. In summary, these results support a model in which CD38 transduces activating signals inside the cell by means of CD3-epsilon and CD3-zeta tyrosine phosphorylation. Moreover, these data identify the CD3-gamma delta epsilon signaling module as a necessary and sufficient component of the TCR/CD3 complex involved in T cell activation through CD38.
ADP-ribosyl Cyclase↗
Mice lacking NK cells develop an efficient Th1 response and control cutaneous Leishmania major infection.
NK cells are believed to play a critical role in the development of immunity against Leishmania major. We recently found that transplantation of wild-type bone marrow cells into neonatal tgepsilon 26 mice, which are deficient in T and NK cells, resulted in normal T cell development, but no or poor NK cell development. Using this novel model we analyzed the role of NK cells in the development of Th1 response and control of cutaneous L. major infection. Mice selectively lacking NK cells (NK-T+) developed an efficient Th1-like response, produced significant amounts of IL-12 and IFN-gamma, and controlled cutaneous L. major infection. Administration of neutralizing IL-12 Abs to NK-T+ mice during L. major infection resulted in exacerbation of the disease. These results demonstrate that NK cells are not critical for development of protective immunity against L. major. Furthermore, they indicate that IL-12 can induce development of Th1 response independent of NK cells in NK-T+ mice following L.major infection.
Animals↗
High- and low-affinity single-peptide/MHC ligands have distinct effects on the development of mucosal CD8alphaalpha and CD8alphabeta T lymphocytes.
In this study, we compared the influence of two peptides on the selection of CD8alphaalpha and CD8alphabeta intraepithelial lymphocytes (IELs) of the intestine, which develop by a unique and partially thymus-independent process. Mice were used in which all T cells carried one transgenic T cell antigen receptor (TCR) (F5), and in which only well defined transgenic peptides were presented by H-2Db. The first peptide, for which the F5 TCR has a high affinity, derives from the influenza virus nucleoprotein (NP68). The second peptide, NP34, is an antagonistic variant of NP68 and is recognized by the F5 TCR with low affinity. To avoid presentation of endogenous peptides or production of T cells carrying alternative TCRs, F5 TCR transgenic mice were generated that were deficient for Tap-1 and Rag-1. In these mice, no CD3(+)CD8(+) cells were found in lymph nodes, spleen, or intestine. Introduction of transgenes encoding either NP34 or NP68 along with an endoplasmic reticulum signal sequence enabled Tap-1-independent expression of each peptide in these mice. Positive selection of F5TCR+CD8(+) thymocytes was not rescued by these transgenic peptides. However, the high-affinity NP68 peptide induced maturation of CD8alphaalpha IEL, whereas the low-affinity NP34 peptide stimulated development of both CD8alphabeta and CD8alphaalpha IEL, but in smaller numbers. When both peptides were present, CD8alphabeta T cells failed to develop and the number of CD8alphaalpha IELs was lower than in mice carrying the NP68 transgene alone. These data demonstrate that single ligands with a high or low affinity for TCR are capable of inducing or inhibiting the maturation of alternative subsets of IELs.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
T lymphocyte development in the absence of CD3 epsilon or CD3 gamma delta epsilon zeta.
CD3 gamma, delta, epsilon, and zeta proteins together with the pre-TCR alpha-chain (pT alpha) and a rearranged TCR beta-chain assemble to form the pre-TCR that controls the double negative (DN) to double positive (DP) stages of thymopoiesis. The CD3 proteins are expressed before pT alpha and TCR beta-chains in prothymocytes and are expressed intracellularly in precursor NK cells, suggesting that the CD3 complex may function independent of pT alpha and TCR beta. In this report, both the role of CD3 epsilon exclusively, and the role of CD3 proteins collectively, in thymocyte and NK cell development were examined. In a mouse strain termed E delta P, a neomycin cassette inserted within the CD3 epsilon promoter abolishes CD3 epsilon and delta expression and also abolishes CD3 gamma expression in all but a small minority (< or =1%) of prothymocytes. These prothymocytes became deficient in CD3 epsilon alone upon reconstitution of CD3 delta expression and were severely, but not completely, arrested at the DN stage, as small numbers of double positive thymocytes were detected. In de facto CD3 gamma delta epsilon zeta(null) mice generated by crossing the epsilon delta P mice with CD3 zeta-/- mice, thymopoiesis were arrested at the CD44-CD25+ DN stage as observed in RAG-/- mice, DJ and VDJ recombination at the TCR beta locus was functional, and normal numbers of NK cells were detected. Together, the findings demonstrate that during thymocyte development, the CD3 complex collectively is not essential until the critical CD44-CD25+ DN stage in which pre-TCR begins to function, whereas CD3 epsilon is critical for the assembly of pre-TCR. Moreover, CD3 proteins are dispensable for NK cell development.
Animals↗
Crystal structures of the XLP protein SAP reveal a class of SH2 domains with extended, phosphotyrosine-independent sequence recognition.
SAP, the product of the gene mutated in X-linked lymphoproliferative syndrome (XLP), consists of a single SH2 domain that has been shown to bind the cytoplasmic tail of the lymphocyte coreceptor SLAM. Here we describe structures that show that SAP binds phosphorylated and nonphosphorylated SLAM peptides in a similar mode, with the tyrosine or phosphotyrosine residue inserted into the phosphotyrosine-binding pocket. We find that specific interactions with residues N-terminal to the tyrosine, in addition to more characteristic C-terminal interactions, stabilize the complexes. A phosphopeptide library screen and analysis of mutations identified in XLP patients confirm that these extended interactions are required for SAP function. Further, we show that SAP and the similar protein EAT-2 recognize the sequence motif TIpYXX(V/I).
Amino Acid Sequence↗
Generation of antigen-specific cytotoxic T lymphocytes and regulation of cytokine production takes place in the absence of CD3zeta.
The TCR-associated protein CD3zeta plays a major role in regulating the state of responsiveness to peptide-MHC complexes on the surface of antigen-presenting cells. In this paper the requirement of CD3zeta in the generation of cytotoxic T cells was compared with its requirement in cytokine gene activation in two mutant mice: ZKO mice with a disrupted CD3zeta gene and ZTG mice in which a truncated CD3zeta segment was expressed as a transgene on the ZKO background. Upon infection of ZTG mice with lymphocytic choriomeningitis virus (LCMV), antigen-specific cytotoxic T lymphocyte (CTL) responses were detected, identical to responses in wild-type mice. In addition, antigen-specific CTL responses to allogeneic class I and class II MHC in ZTG animals were indistinguishable from those in wild-type animals. However, CTL responses to the same major antigens were not detectable in ZKO mice. We conclude that the signal transduction pathways leading to CTL development and cytokine production can be triggered through TCR in the absence of functional CD3zeta, provided the remainder of the TCR-CD3 complex is expressed at high levels on the cell surface. Surprisingly, IFN-gamma production in response to LCMV followed the same kinetics in ZKO, ZTG and wild-type mice. However, in vitro studies showed that cytokine production in general was abnormally regulated in T lymphocytes from ZKO mice, in contrast to ZTG T cells. Taken together, these studies support the hypothesis that development of CTL can take place in the absence of functional CD3zeta. However, CTL development requires stronger TCR-initiated signal transduction events than induction of cytokine genes.
Abatacept↗
A mouse carrying genetic defect in the choice between T and B lymphocytes.
Transgenic mice with human CD3epsilon gene have been shown to exhibit early arrest of T cell development in the thymus. The present study shows that, instead of T cells, B cells are generated in the thymus of a line, tg epsilon26, of the human CD3epsilon transgenic mice. The accumulation of mature B cells in the thymus was found only in tg epsilon26 mice, not in other human CD3epsilon transgenic mouse lines or other T cell-deficient mice, including CD3-epsilon knockout mice and TCR-beta/TCR-delta double knockout mice. Hanging drop-mediated transfer into 2-deoxyguanosine-treated thymus lobes showed that lymphoid progenitor cells rather than thymus stromal cells were responsible for abnormal B cell development in tg epsilon26 thymus, and that tg epsilon26 fetal liver cells were destined to become B cells in normal thymus even in the presence of normal progenitor cells undergoing T cell development. These results indicate that lymphoid progenitor cells in tg epsilon26 mice are genetically defective in thymic choice between T cells and B cells, generating B cells even in normal thymus environment. Interestingly, tg epsilon26 thymocytes expressed GATA-3 and TCF-1, but not LEF-1 and PEBP-2alpha, among T cell-specific transcription factors that are involved in early T cell development, indicating that GATA-3 and TCF-1 expressed during thymocyte development do not necessarily determine the cell fate into T cell lineage. Thus, tg epsilon26 mice provide a novel mouse model in that lineage choice between T and B lymphocytes is genetically defective.
Animals↗
Essential and partially overlapping role of CD3gamma and CD3delta for development of alphabeta and gammadelta T lymphocytes.
CD3gamma and CD3delta are two highly related components of the T cell receptor (TCR)-CD3 complex which is essential for the assembly and signal transduction of the T cell receptor on mature T cells. In gene knockout mice deficient in either CD3delta or CD3gamma, early thymic development mediated by pre-TCR was either undisturbed or severely blocked, respectively, and small numbers of TCR-alphabeta+ T cells were detected in the periphery of both mice. gammadelta T cell development was either normal in CD3delta-/- mice or partially blocked in CD3gamma-/- mice. To examine the collective role of CD3gamma and CD3delta in the assembly and function of pre-TCR and in the development of gammadelta T cells, we generated a mouse strain with a disruption in both CD3gamma and CD3delta genes (CD3gammadelta-/-). In contrast to mice deficient in either CD3gamma or CD3delta chains, early thymic development mediated by pre-TCR is completely blocked, and TCR-alphabeta+ or TCR-gammadelta+ T cells were absent in the CD3gammadelta-/- mice. Taken together, these studies demonstrated that CD3gamma and CD3delta play an essential, yet partially overlapping, role in the development of both alphabeta and gammadelta T cell lineages.
Animals↗
The X-linked lymphoproliferative-disease gene product SAP regulates signals induced through the co-receptor SLAM.
In addition to triggering the activation of B- or T-cell antigen receptors, the binding of a ligand to its receptor at the cell surface can sometimes determine the physiological outcome of interactions between antigen-presenting cells, T and B lymphocytes. The protein SLAM (also known as CDw150), which is present on the surface of B and T cells, forms such a receptor-ligand pair as it is a self-ligand. We now show that a T-cell-specific, SLAM-associated protein (SAP), which contains an SH2 domain and a short tall, acts as an inhibitor by blocking recruitment of the SH2-domain-containing signal-transduction molecule SHP-2 to a docking site in the SLAM cytoplasmic region. The gene encoding SAP maps to the same area of the X chromosome as the locus for X-linked lymphoproliferative disease (XLP) and we found mutations in the SAP gene in three XLP patients. Absence of the inhibitor SAP in XLP patients affects T/B-cell interactions induced by SLAM, leading to an inability to control B-cell proliferation caused by Epstein-Barr virus infections.
Amino Acid Sequence↗
T cell-mediated pathology in two models of experimental colitis depends predominantly on the interleukin 12/Signal transducer and activator of transcription (Stat)-4 pathway, but is not conditional on interferon gamma expression by T cells.
The requirements for interleukin (IL)-12/signal transducer and activator of transcription (Stat)-4 signaling and induction of T cell-specific interferon (IFN)-gamma expression in the development of T helper cell (Th)1-type pathology were examined in two different models of experimental colitis. In each model, abnormal reconstitution of the T cell compartment in immunodeficient mice by adoptive cell transfer leads to a wasting syndrome and inflammation of the colon, induced by IFN-gamma and tumor necrosis factor (TNF)-alpha-producing T cells. We show here that treatment with anti-IL-12 antibodies in one of the models, or reconstitution with T cells from Stat-4-deficient (Stat-4(null)) mice in both models resulted in a milder disease in the majority of recipient animals, compared with those that were left untreated or that had been reconstituted with wt cells. Protected mice in each group also harbored lower frequencies of IFN-gamma-producing T cells than did diseased mice, suggesting that effects on wasting and colitis resulted from the attenuation of IFN-gamma expression by T cells. To test whether the development of pathogenic T cells in the two colitis models was directly dependent on T cell-specific IFN-gamma expression, IFN-gammanull donors were used for T cell reconstitution in each system. Surprisingly, large numbers of IFN-gammanull-reconstituted mice developed wasting and colitis, which in many cases was of comparable severity to that seen in animals reconstituted with wt cells. Furthermore, T cells from these animals expressed TNF-alpha, demonstrating that they had retained the ability to produce another proinflammatory cytokine. Taken together, these results demonstrate that in some forms of chronic experimental colitis the development of pathogenic T cells is influenced predominantly, though not exclusively, by IL-12 via the actions of Stat-4 proteins. Furthermore, our data suggest that in the models of colitis studied here the effects of IL-12/Stat-4 or other Th1 promoting pathways are not limited to the induction of IFN-gamma gene expression in T lymphocytes.
Animals↗
Monoallelic expression of the interleukin-2 locus.
The lymphokine interleukin-2 (IL-2) is responsible for autocrine cell cycle progression and regulation of immune responses. Uncontrolled secretion of IL-2 results in adverse reactions ranging from anergy, to aberrant T cell activation, to autoimmunity. With the use of fluorescent in situ hybridization and single-cell polymerase chain reaction in cells with different IL-2 alleles, IL-2 expression in mature thymocytes and T cells was found to be tightly controlled by monoallelic expression. Because IL-2 is encoded at a nonimprinted autosomal locus, this result represents an unusual regulatory mode for controlling the precise expression of a single gene.
Alleles↗
Both the lymphotoxin and tumor necrosis factor pathways are involved in experimental murine models of colitis.
BACKGROUND & AIMS: Membrane lymphotoxin (LT) alpha/beta, a member of the tumor necrosis factor (TNF) family of immune regulatory molecules, is involved both in the development of secondary lymphoid tissues and the maintenance of organized lymphoid tissues in the adult. Defects observed in the mucosal immune system in animals with a genetically disrupted LTalpha/beta pathway coupled with the expression of LTalpha/beta in activated T cells motivated an examination of the importance of this pathway in experimental colitis. METHODS: Soluble LTbeta receptor (LTbetaR) immunoglobulin fusion protein was used to inhibit the LTalpha/beta/light axis in two independent rodent models of colitis: CD45RBhi CD4(+)-reconstituted SCID mice and bone marrow-transplanted tg26 mice (BM --> tg26). RESULTS: Treatment with LTbetaR immunoglobulin attenuated the development of both the clinical and histological manifestations of the disease in these two murine models of colitis. Given the success of TNF inhibitors in the treatment of human Crohn's disease, the effects of LTbetaR immunoglobulin have been compared with antibody to TNF in the BM --> tg26 model, and both treatments were equally efficacious. CONCLUSIONS: The LT pathway plays a role in the development of colitis as important as that of the TNF system and, therefore, represents a potential novel intervention point for the treatment of inflammatory bowel disease.
Animals↗
Consequences of Fas-ligand and perforin expression by colon T cells in a mouse model of inflammatory bowel disease.
BACKGROUND & AIMS: We describe a type of colitis that develops after transplantation of nonallogeneic wt bone marrow cells into T cell- and natural killer cell-deficient Tg26 mice (BM-->Tg26). In these animals, severe wasting and inflammation of the colon correlates with the expansion of mucosal T lymphocytes that displays cytotoxic activity. The aims of this study were to determine the relative contribution of perforin and Fas ligand (Fas-L) expression to the cytotoxic action of these T cells and to examine the influence of each pathway in this model of colitis. METHODS: Colonic T cells were tested for their ability to mediate Fas- and perforin-dependent killing in redirected cytotoxicity assays. Bone marrow cells from donor mice lacking either Fas-L (gld mice) or perforin (PFPnull mice) or both molecules were used to reconstitute Tg26 mice. RESULTS: Colon cytotoxic T lymphocyte displayed both Fas- and perforin-dependent killing. Deficiency in perforin, but not Fas-L, resulted in reduced incidence of wasting and, to a lesser extent, severe colitis in BM-->Tg26 animals. CONCLUSIONS: Colon T cells from BM-->Tg26 mice express both perforin and Fas-L. Although neither pathway is critical in the development of colitis, perforin does have a measurable influence on disease in the BM-->Tg26 colitis model.
Animals↗
pANCA represents a cross-reactivity to enteric bacterial antigens.
pANCA (perinuclear antineutrophil cytoplasmic antibodies) occur at a high frequency in patients with ulcerative colitis. The purpose of this study was to investigate the frequency of pANCA in different mouse models of colitis and to determine whether there is any cross-reactivity of pANCA with bacterial antigens. Sera from 146 colitic mice and controls and from 30 patients with ulcerative colitis were tested for the presence of pANCA by indirect immunofluorescence with or without prior absorption with homogenized murine cecal bacteria. pANCA was found in 24 of 36 IL10(-/-) mice. In contrast to the human pANCA, both nuclear and perinuclear staining was found. Absorption of either human or mouse pANCA-positive sera with enteric bacterial antigens greatly reduced or abolished the specific perinuclear staining of pANCA. We conclude that pANCA occurs not only in humans but also in IL19(-/-) mice with colitis and likely represents a cross-reactivity with enteric bacterial antigens.
Animals↗
Activation-induced apoptosis of mature T cells is dependent upon the level of surface TCR but not on the presence of the CD3 zeta ITAM.
Activation-induced cell death (AICD) occurs primarily in recently activated T cells after a second TCR triggering. Since a threshold in the activation status may be critical for AICD, it is likely that the CD3 ITAM, docking sites for tyrosine kinases, regulate AICD. A 'threshold model' for AICD was tested by using two targeted mutant mouse strains lacking either the zeta chain (CD3zeta-/-) or the ITAM of the zeta chain (CD3zeta-/-:Tgzetadelta67-150). Although the T cells from the CD3zeta-/- mice express extremely low levels of surface TCR, a subpopulation (approximately 18%) of activated T cells could be induced to express TCR/FcepsilonRI gamma by using a powerful polyclonal activation protocol. These activated TCR/FcRI gamma T cells were capable of undergoing AICD, but its induction required 10 times as much anti-CD3epsilon mAb as that required for AICD of wild-type T cells. Thus, the intensity of AICD correlated with the level of CD3 expression and was less efficient with activated, CD3zeta(-/-)-derived T cells. By contrast, AICD of T cells from the CD3zeta-/-:Tgzetadelta67-150 mice could be induced with low doses of anti-CD3epsilon mAb and the extent of AICD was comparable to T cells from wild-type mice. The AICD induced in T cells from CD3-/-, CD3zeta-/-:Tgzetadelta67-150 and normal controls was specifically inhibited by Fas-Ig fusion proteins. Our data support the 'threshold model' of AICD by demonstrating that AICD is controlled by the strength of T cell activation.
Animals↗
Expression of a CD3 epsilon transgene in CD3 epsilon(null) mice does not restore CD3 gamma and delta expression but efficiently rescues T cell development from a subpopulation of prothymocytes.
The TCR-associated CD3 complex consists of four subunits, i.e. CD3 gamma, delta, epsilon and zeta, which are expressed very early in T cell development prior to the expression of the TCR and the pre-TCR alpha chain. It is unclear whether the expression of each CD3 protein is independent of, or is influenced by, other CD3 subunits. To study whether CD3 epsilon regulates expression of CD3 gamma and delta genes, we generated a strain of CD3 epsilon-deficient mice termed CD3 epsilon(delta P/delta P) (epsilon(delta P)), in which the promoter of CD3E was disrupted, and subsequently reconstituted these mice with a CD3 epsilon transgene. In the epsilon(delta P) mice, T cell development is arrested at the double-negative stage and targeting the CD3 epsilon gene caused severe inhibition of CD3 gamma and delta gene expression. Introduction of the CD3 epsilon transgene did not restore CD3 gamma and delta expression. However, a very small fraction of prothymocytes that expressed CD3 gamma and delta was rescued upon reconstitution of the CD3 epsilon transgene. Remarkably, this rescue led to a very efficient differentiation and maturation of thymocytes, resulting in a significant T cell population in the periphery. These results demonstrate that CD3 epsilon does not regulate expression of CD3 gamma and delta genes, and underscore the capacity of each prothymocyte to give rise to a large number of mature peripheral T cells.
Animals↗