Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0393754 (HSA)
 2,996 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MRL-Mp-lpr/lpr mice contain phenotypically abnormal populations of T cells, and exhibit an SLE-like autoimmune disease in which autoantibodies are a prominent feature. We analyzed the phenotype and T-cell receptor V beta expression pattern in CD4+ T cells of this mutant mouse strain to detect abnormalities that could explain the autoimmunity. The CD4+ T cells contain two distinct abnormal populations. One of these expresses B220 and HSA, and in these and other respects closely resembles the accumulating CD4-CD8- population. The other expresses a high level of CD44 (Pgp-1), and a high level of the 16A epitope of CD45, and so resembles post-activation T cells. Both of these cell types are exclusive to MRL-Mp-lpr/lpr. We also identified V beta 5- and V beta 11-positive CD4+ T cells, in both MRL-Mp-lpr/lpr and MRL-Mp-+/+ mice. We conclude that autoimmune T cells can be detected in these mice, but that they are not the cause of the accumulation of abnormal CD4+ and CD4-CD8- cells.
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PMID:Self-reactivity and the expression of memory markers vary independently in MRL-Mp+/+ and MRL-Mp-lpr/lpr mice. 134 99

We have examined fetal thymic development in the trisomy 16 (Ts16) mouse, which is considered to be a model for human trisomy 21, or Down Syndrome. The Ts16 thymus contains 10 to 20% of the number of lymphocytes found in a normal thymus at a comparable stage. Expression of thymocyte differentiation markers (Thy-1, CD5, CD8, CD4, CD3, and HSA) is severely affected in Ts16 fetuses aged 14-18 gestational days. When thymuses from 14-day Ts16 mice were cultured in vitro, these markers eventually reached levels of expression comparable to those seen in normal thymuses in culture. On the other hand, expression of CD44 appears to be unaffected in Ts16 thymuses in vivo, but declines in vitro relative to normal thymuses. Reconstitution of depleted thymic stroma with thymocytes showed evidence of defects in both developmental compartments.
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PMID:Defects in thymocyte differentiation and thymocyte-stromal interactions in the trisomy 16 mouse. 137 32

In the present report we describe a CD4+8- heat stable antigen-negative (HSA-) thymocyte subpopulation that expresses a distinguishably low density of alpha beta T-cell antigen receptors (TCRlo) from the majority of CD4+8- high-density TCR (TCRhi) mature-type thymocytes. This subpopulation appears relatively late in life. Analysis of MEL-14, Pgp-1 (CD44), ICAM-1 (CD54), and NK1.1 expression on this subpopulation revealed that the CD4+8- TCRlo population was a population having unique characteristics (MEL-14-, CD44+, ICAM-1+, and NK1.1+) compared to the CD4+8- TCRhi thymocytes, most of which are MEL-14+, CD44-, ICAM-1-, and NK1.1-. When TCR beta-chain variable region (V beta) usage was analyzed, this thymic population expressed predominantly products of V beta 7 and V beta 8.2 TCR gene families. Interestingly, cells with V beta 8.1 TCRs, which are reactive to Mls-1a antigens, were not eliminated from the CD4+8- HSA- TCRlo subpopulation but had been eliminated from the major CD4+8- HSA- TCRhi subpopulation in Mls-1a strains. A subset with a phenotype similar to the CD4+8- HSA- TCRlo thymocytes was also identified primarily in bone marrow, and this subset constituted approximately half of the CD4+ T cells in the bone marrow. The CD4+8- HSA- TCRlo cells showed extremely high proliferative responses to immobilized anti-TCR antibody but generated negligible responses to allogeneic H-2 antigens compared to the responses generated by the major CD4+8- HSA- CD3hi cells. However, the CD4+8- HSA- TCRlo cells in Mls-1b mice mounted vigorous proliferative responses to Mls-1a antigens but not in Mls-1a mice. The properties of this T-cell subset suggest that these cells belong to a lineage distinct from the major T-cell population.
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PMID:An NK1.1+ CD4+8- single-positive thymocyte subpopulation that expresses a highly skewed T-cell antigen receptor V beta family. 137 29

In a previous study, we raised a mAb (MTS 35) reacting with a plasma membrane Ag expressed on both cortical thymocytes and a subset of thymic medullary epithelial cells. In view of the shared expression of this molecule, we have defined it as thymic shared Ag-1 (TSA-1). Considering its selective reactivity with cortical, but not medullary thymocytes, the relevance of TSA-1 as a marker of immature T cells was investigated in detail in this study, using multicolor flow cytometric analysis. TSA-1 was found on all immature thymocyte subsets (CD3-4-8-, CD3-4+8-, CD3-4-8+, CD3-4+8+, CD3low4+8+). Conversely, CD3high4+8- and CD3high4-8+ thymocytes, early thymic migrants and peripheral T cells were TSA-1-. More refined gating and analysis of the transitional CD3intermediate/high4+8+ thymocytes, proposed candidates for negative selection, demonstrated that approximately one half were TSA-1-. In fact, there was a directly inverse relationship between TSA-1 and CD3 expression on thymocytes. In the periphery, TSA-1 was detected on B lymphocytes. TSA-1 is PI-linked and has a molecular mass of 17 kDa nonreduced, or 12 to 13 kDa reduced. Through cross-correlation analysis, this molecule was distinct from H-2K, PNA-R, CD5, CD11a/18, Thy-1, HSA, Ly6A/E, Ly6C, ThB, CD25, CD44. Hence TSA-1 appears to be a unique marker which exquisitely separates mature from immature thymocytes.
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PMID:Thymic shared antigen-1. A novel thymocyte marker discriminating immature from mature thymocyte subsets. 153 95

Immunization of mice for contact sensitivity induces two different antigen-specific Thy-1+ cell activities that are required to act in sequence for elicitation of contact sensitivity. In this study, 2,4-dinitro-1-fluorobenzene contact sensitivity responses in BALB/c and C3H/He mice demonstrated the importance of early-acting and antigen-specific contact sensitivity-initiating cells to recruit the classical, late-acting contact sensitivity effector T cells. Employing in vitro treatment of sensitized cells with monoclonal antibodies to cell surface determinants and then incubation in complement, prior to adoptive cell transfer, the contact sensitivity-initiating cells were shown to have a surface phenotype that is quite unusual for antigen-specific cells [Thy-1+, CD5+, CD3-, CD4-, CD8-, sIg-, B220+, major histocompatibility complex class II-, CD23+, IL-2R-, IL-3R+, Mel-14-, CD44+ (Pgp-1+), J11d+ (HSA+), MAC-1+, LFA-1+, and Fc gamma IIR+], and is quite different from the late-acting, contact sensitivity-effector T cells (Thy-1+, CD5+, CD3+, CD4+, CD8-, sIg-, B220-, major histocompatibility complex class II-, CD23-, IL-2R+, IL-3R-, and CD44- (Pgp-1-), J11d-(HSA-), MAC-1-, LFA-1+, Fc gamma IIR-). Contact sensitivity initiation was required for elicitation of late 24-h 2,4-dinitro-1-fluorobenzene contact sensitivity responses, in both BALB/c and C3H/He mice. Moreover, relatively high doses of some monoclonal antibodies [anti-B220 (CD45RA) and anti-CD23 (IgE Fc epsilon II receptor)] were necessary to completely eliminate all contact sensitivity-initiating cells that permitted expression of late contact sensitivity-effector T-cell activity. In contrast, high doses of monoclonal antibody specific for surface determinants of late-acting contact sensitivity effector T cells (anti-CD3 and anti-CD4), when used in high doses similar to anti-B220 and anti-CD23, had no effect on contact sensitivity-initiating cell activity. Our results indicate that two very different antigen-specific Thy-1+ cells are necessary to elicit 2,4-dinitro-1-fluorobenzene contact sensitivity in BALB/c and C3H/He mice.
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PMID:DNFB contact sensitivity (CS) in BALB/c and C3H/He mice: requirement for early-occurring, early-acting, antigen-specific, CS-initiating cells with an unusual phenotype (Thy-1+, CD5+, CD3-, CD4-, CD8-, sIg-, B220+, MHC class II-, CD23+, IL-2R-, IL-3R+, Mel-14-, Pgp-1+, J11d+, MAC-1+, LFA-1+, and Fc gamma RII+). 750 36

Fas is an apoptosis-related cell surface molecule whose defective transcription results in the lpr defect and autoimmunity. Recent analysis of Fas mRNA and protein expression in normal mice showed high expression in the thymus, on activated T cells, and on 5-10% of peripheral T cells. To investigate the role of Fas in the thymus, we analyzed its expression in fetal and adult thymocyte subsets. Fas was not expressed on fetal nor adult CD8-CD4- (double-negative, DN) T cell precursors. The earliest precursors that expressed low levels of FAS were the immediate precursors of DP thymocytes that bear the CD44-CD25-CD8loCD4loTCRlo phenotype. Other DN cells that expressed Fas appeared to be either non-T cells or mature alpha beta + DN thymocytes. The onset of Fas expression followed the onset of expression of CD8 and CD4 and Fas expression reached its peak in CD8+CD4+ double-positive (DP) thymocytes. Both single-positive (SP) subsets were largely Fas+ (CD8 SP < CD4 SP) but expressed lower levels of Fas than DP cells. However, a majority (> 60%) of the most mature HSA(lo) SP cells (2-5% of all SP thymocytes) were Fas- and the remainder of the HSA(lo) SP cells was Fas(lo). We observed two main differences between Fas expression on fetal versus adult thymocytes. First, up to 90% of fetal gamma delta + DN cells expressed high levels of Fas, in contrast to the very low expression (< 7% Fas+ cells) among adult gamma delta + thymocytes. Second, whereas virtually all adult DP cells were Fas+, up to 75% of fetal day 16 DP cells were Fas-.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The onset of Fas expression parallels the acquisition of CD8 and CD4 in fetal and adult alpha beta thymocytes. 751 29

The elicitation in immunized mice of delayed-type hypersensitivity (DTH) responses to nickel sulfate (NiSO4) was found to be mediated by the sequential activities of two different antigen-specific Thy-1+ cells. Early-acting (2-hr) NiSO4-specific, DTH-initiating cells were required for elicitation of subsequent 24-hr NiSO4-specific DTH and had an unusual phenotype for an antigen-specific cell (Thy-1+, CD5+, CD3-, CD4-, CD8- CD23+, CD45RA+ (B220+), IL-2R-, IL-3R+, sIg-, MHC Class II-, Mel-14-, CD44+ (Pgp-1+), J11d+ (HSA+), MAC-1+, LFA-1, and Fc gamma II-R+). In contrast, the late-acting, NiSO4-specific DTH-effector T cells were: Thy-1+, CD5+, CD3+, CD4+, CD8-, CD23-, B220-, IL-2R+, IL-3R-, sIg-, MHC Class II-, Mel-14+, CD44- (Pgp-1-), J11d- (HSA-), MAC-1-, LFA-1+, and Fc gamma II-R-. Our results led us to surmise that the early-acting DTH-initiating cells were necessary to locally recruit the late-acting effector T cells. Relatively high doses of anti-B220 (CD45RA) and anti-CD23 (IgE Fc epsilon RII receptor) monoclonal antibodies were necessary to completely eliminate all DTH-initiating cells, and therefore completely block subsequent expression of some late NiSO4-specific DTH activity that was due to the late-acting DTH effector T cells. In addition, we found that mast cells were important for expression of early-acting, DTH-initiating cell activity in this NiSO4-specific, DTH system. This was probably due to the absence of mast cells in mast cell-deficient WBB6F1-W/Wv mice. Our results indicated that two different antigen-specific Thy-1+ cells are necessary to elicit NiSO4-specific DTH in mice and that mast cells are necessary for expression of the early component that is due to early-acting, DTH-initiating cells.
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PMID:Elicitation of nickel sulfate (NiSO4)-specific delayed-type hypersensitivity requires early-occurring and early-acting, NiSO4-specific DTH-initiating cells with an unusual mixed phenotype for an antigen-specific cell. 769 35

Transgenic (TG) mice with TCR alpha and beta chain genes from a CD4-dependent auto-I-Ak reactive T cell clone were generated. H-2k TG mice had a large number of thymic and splenic CD4 T cells expressing the autoreactive TCR without manifestation of autoimmunity. The cells were not anergic, as they could respond to autologous antigen presenting cells and anti-TCR antibodies in vitro to proliferate and to produce interleukins. Various degrees of down-regulation of CD2 and CD44 was observed in TG mice, indicating the presence of a defective co-stimulatory process in TG T cells. These features indicate that the self tolerance in autoreactive TCR TG mice is due not to clonal deletion and anergy but to a novel mechanism where T cells cannot sufficiently respond to normally existing self ligand in vivo. That such an in vivo unresponsiveness of autoreactive T cells is dictated in the thymus during CD4 T cell differentiation atypical form of positive selection of autoreactive T cells was suggested by the abnormal surface expression of CD69 and HSA.
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PMID:A novel form of self tolerance dictated in the thymus of transgenic mice with autoreactive TCR alpha and beta chain genes. 801 99

Beta 7 is expressed on subsets of thymocytes, while T and B lymphocytes show heterogeneous expression of beta 7. Here, we examine the phenotype of the thymocyte and lymphocyte subsets which express alpha 4 beta 7 and alpha E beta 7 using mAb against alpha E, beta 7 and mAb DATK32 which recognizes a combinatiorial epitope on alpha 4 beta 7+ thymocytes have a mature phenotype: TcR+, CD11a(hi)CD44(hi)HSA(dull). Small subsets of double-negative CD4-CD8-, single-positive CD4+ and CD8+ thymocytes express beta 7, while double-positive CD4+CD8+ thymocytes are beta 7-. However, two integrins alpha E beta 7 and alpha 4 beta 7 recognized by anti-beta 7 are not expressed on an identical subpopulation of thymocytes, as alpha E beta 7+ alpha 4 beta 7-, alpha E beta 7 + alpha 4 beta 7+ and alpha E beta 7- alpha 4 beta 7+ thymocyte subsets are evident. Similarly, intraepithelial lymphocytes express high levels of alpha E beta 7 but little alpha 4 beta 7. In the spleen, Peyer's patches and lymph nodes, alpha 4 beta 7 is expressed at higher levels on most B lymphocytes than on the majority of T lymphocytes, while a small subset of T lymphocytes, which includes both CD4+ and CD8+ lymphocytes, express high levels of beta 7 in the form of alpha 4 beta 7 and alpha E beta 7, although, as observed with lymphocytes, not all alpha 4 beta 7 hi CD4+ lymphocytes expressed alpha 4 beta 7. The population of alpha 4 beta 7 hi CD4 lymphocytes are enriched in Peyer's patches and form subsets of the memory CD4+ lymphocyte population, which can be further subdivided on the basis of alpha E beta 7, L-selectin and alpha 4 expression. Therefore, memory CD4+ lymphocytes are highly heterogeneous in their expression of adhesion receptors, and presumably these subpopulations will exhibit very different trafficking properties.
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PMID:Distribution of alpha 4 beta 7 and alpha E beta 7 integrins on thymocytes, intestinal epithelial lymphocytes and peripheral lymphocytes. 862 86

Antigen recognition signals by the TCR are transduced through activation motifs present in the cytoplasmic region of CD3 chains. In vitro analysis has suggested that the CD3zeta chain mediates different signals from other CD3 chains. To analyze the in vivo function of CD3zeta-mediated signals for T cell development, mice expressing a mutant CD3zeta chain lacking all the activation motifs were generated by introducing the transgene into zeta-knockout mice. Mature CD4(+) single-positive (SP) thymocytes in these mice were greater in number than in zeta-deficient mice, and the promoted differentiation was indicated by the changes of CD69 and HSA phenotypes. We found that even in the absence of activation motifs in CD3zeta, these mature cells became functional, being able to induce Ca2+ mobilization and proliferation upon stimulation. On the other hand, CD4(-)CD8(-) double-negative (DN) thymocytes, most of which were arrested at the CD44(-)CD25(+) stage similarly to those in zeta-deficient mice, could not be promoted for differentiation into CD4(+)CD8(+) double-positive thymocytes in these mice in spite of the fact that the expression of the transgene in DN thymocytes was higher than that of zeta in wild-type mice. These results demonstrate the preferential dependence of the promotion of development and/or expansion of DN thymocytes rather than mature thymocytes upon the activation signals through the zeta chain and suggest differential requirements of TCR signaling for mature SP and immature DN thymocyte developments in vivo.
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PMID:Preferential requirement of CD3 zeta-mediated signals for development of immature rather than mature thymocytes. 875 51


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