T suppressor cell growth factor and anti-CD3 antibodies stimulate reciprocal subsets of T lymphocytes

Because of the central role of IL-2 in clonal expansion of T cells, we have postulated that lymphocyte subpopulations with opposing regulatory functions might be independently regulated by differential requirements for expression of cell-surface IL-2-R. Purified CD4+ and CD8+ cells proliferated in an IL-2-dependent manner to crosslinked anti-T cell receptor antibodies (anti-CD3-Seph). Similarly, both CD4+ and CD8+ cells became IL-2 responsive after incubation in T suppressor cell growth factor (TsGF), a newly described approximately 8,000 Mr product of activated CD4+ cells. In support of our hypothesis, however, we observed that subpopulations of CD4+ and CD8+ cells, possessing distinct cell-surface antigens, showed differential responses to these stimuli. Those cells of suppressor-inducer or suppressor-effector phenotype failed to proliferate when cultured in anti-CD3-Seph plus IL-2, but did proliferate in an IL-2-dependent manner to TsGF. Furthermore, the suppressor-effector population was unresponsive to TsGF plus IL-2 when cocultured in anti-CD3-Seph, suggesting that functionally induced Ts may be refractory to growth stimuli. Conversely, cells with helper-inducer or cytolytic phenotype proliferated when incubated in anti-CD3-Seph and IL-2, while remaining essentially unresponsive to TsGF and IL-2. The results could not be explained by differences in the level of CD3 expression by the T cell subsets. Thus, cells within the helper and suppressor lineages appear to have distinct and reciprocal patterns for the induction of IL-2 responsiveness.     

Immunoregulatory subsets of the T helper and T suppressor cell populations in homosexual men with chronic unexplained lymphadenopathy

Unexplained, generalized lymphadenopathy in homosexual men, which can be a prodrome to the acquired immunodeficiency syndrome, is associated with impaired cell-mediated immunity, a low ratio of T helper-inducer to T suppressor-cytotoxic cells (defined by the T4 and T8 monoclonal antibodies), and hypergammaglobulinemia. We performed double-marker studies on T cells by using a panel of monoclonal antibodies (Ia, T17, TQ1, and Leu-8), which reportedly detect activation or functional subsets of the T4 and T8 T cell populations. The T4:TQ1- or T4:Leu-8- subset, which is the major helper subset for B cell responses, is normally represented in lymphadenopathy patients. A depression in the reciprocal subset, T4:TQ1+ or T4:Leu-8+, accounts for the T4 T cell defect. Similarly, the TQ1 and Leu-8 markers delineate the abnormality of T8 T cells: the T8:TQ1- or T8:Leu-8- subset is elevated, whereas the T8:TQ1+ or T8:Leu-8+ subset is normally represented. We found no evidence of excessive activation of T4 T cells by using the T17 or Ia monoclonal antibodies. We did find an overall increase in Ia-positive T cells; however, this was due to increased T8:Ia+ cells. In functional studies, immunoglobulin production induced by pokeweed was subnormal. Most lymphadenopathy patients had normal T helper cell function when combined with normal B cells. The dampened pokeweed responses could be partially explained by depression of the T4:TQ1+ (or T4:Leu-8+) subset (which has minor help-associated function) and/or greater than expected suppression. However, subnormal pokeweed responses could not be totally explained by immunoregulatory T cell abnormalities because we also found an intrinsic defect in the B cell responses of lymphadenopathy patients.     

Effect of oral colchicine on T cell subsets, monocytes and concanavalin A-induced suppressor cell function in asthmatic patients

Asthmatic patients have a deficiency of concanavalin A-(Con A) induced suppressor cell function. We tested whether oral colchicine 0.5 mg twice daily for 7 days could correct this immunoregulatory abnormality. Peripheral blood mononuclear cells were incubated with Con A and then suppression of proliferation was measured by coculture of these cells with healthy volunteers' mononuclear cells and phytohaemagglutinin. Sixteen asthmatic patients had significantly (P less than 0.002) decreased Con A-induced suppressor cell function (17.0 +/- 17.2%, mean +/- s.d.) as compared to 13 healthy volunteers (37.9 +/- 14.9%). Oral colchicine significantly (P less than 0.05) increased, though only partially corrected, these 16 asthmatic patients' Con A-induced suppressor cell function (28.1 +/- 14.3%). Asthmatic patients had an increased number of monocytes (691 +/- 289 vs 388 +/- 271/mm3 for normals, P less than 0.01) and a normal number of lymphocytes, Leu 4+ total T cells, Leu 3+ helper/inducer T cells, and Leu 2+ suppressor/cytotoxic T cells as well as a normal Leu 3/Leu 2 ratio. Oral colchicine significantly (P less than 0.005) decreased the number of monocytes (451 +/- 255/mm3) without significantly affecting the number of lymphocytes, Leu 4+, Leu 3+, or Leu 2+ T cells, or the Leu 3/Leu 2 ratio. These results are consistent with the hypothesis that the deficiency of Con A-induced suppressor cell function in asthmatic patients may be due, in part, to an increased number and/or abnormal activity of monocytes. If so, then oral colchicine may have partially corrected the deficiency of Con A-induced suppressor cell function by decreasing the number and/or modulating the activity of monocytes.     

细胞因子信号转导抑制因子（SOCS）与免疫调节

细胞因子信号转导抑制因子（suppressor of cytokine signaling,SOCS）是一类可由多种细胞因子诱导产生,又能通过多种途径对细胞因子的信号转导进行负向调节的蛋白质分子。众多研究发现SOCS蛋白家族是一个非常重要的可以负向调节 JAK／STAT信号通路的分子家族。本文将着重阐述介绍SOCS家族在炎症和自身免疫性疾病中的作用。     

CFU-GM and T cell subsets in young red cell collections

Young red cells (YRBCs) prepared using cell separators contain large numbers of white cells. The absolute numbers and percentages of different lymphocyte subsets and progenitor cells in YRBC collections were assessed before and after filtration through two white cell filters. It was found that the filters do not take up or selectively allow through any one lymphocyte subset and that the absolute number of T cells and progenitor cells in YRBC collections after filtration is less than that in normal donor blood.     

Null cell immunoregulation in SLE

Fresh normal T cells do not lyse MDA-157 target cells. Normal null cells, cultured for 4 days with MDA-157 stimulators, and then mixed overnight with fresh normal T cells, induce cytotoxicity on MDA-157 targets and suppressor activity in the T-cell acceptor population. With the same normal acceptor T cells, MDA-157 activated null cells from 13/18 patients with Systemic Lupus Erythematosus (SLE), unlike activated cells from a disease control population, induce little or no T-cell cytotoxicity or suppression. These results provide further evidence for abnormal null cell function in SLE.     

Distribution of T cell subsets in human lymph nodes

A series of T cell-specific monoclonal antibodies was used to determine the location of T lymphocyte subpopulations in frozen sections of human lymph nodes by means of an immunoperoxidase technique. The majority of cells in the paracortical regions were reactive with anti-T1 and anti-T3 antibodies, which define all mature peripheral T cells. In contrast, the majority of cells within primary follicles were unreactive with anti-T1 and anti-T3 antibodies, but were reactive with anti-Ia and anti-IgM antibodies. In addition, a substantial number of T1+, T3+ cells were found in the germinal centers of secondary follicles on the capsular side. The vast majority of T1+, T3+ cells in the paracortex and the follicles were reactive with anti-T4 antibody, which defines inducer/helper T cells. Only a minority of cells in these areas were reactive with anti-T5 and anti-T8 antibodies, which define cytotoxic/suppressor cells. No lymphocytes were stained with anti-T6 antibody, which reacts with a majority of thymocytes but not with peripheral T cells. Scattered cells in the paracortex showed staining for Ia antigen in an irregular dendritic pattern. The findings demonstrate that the major T cell population found within human lymph node bears the mature T1+, T3+, T4+ phenotype characteristic of inducer T cells. Moreover, the location of this population indicates that they play a role in the induction of B cell differentiation in vivo.     

The selective expansion of functional T cell subsets

Adoptive cellular immunotherapy is considered a potential treatment for a wide range of diseases, including cancer, infectious diseases, and autoimmune disorders. We have developed a method using a conditioned medium, XLCM, that selectively expands several different T cell subsets with a view to their use in cell therapy. Primary FBS-free suspension cultures of human peripheral blood low-density mononuclear cells treated with XLCM reproducibly expand over 100,000-fold within a period of 4 weeks. CD4+ T cells and CD8+ T cells expand sequentially in the unfractionated cultures, and relatively pure populations of CD4+ and CD8+ T cells may be expanded from populations first enriched in the respective T cell subset. CD4+ T cells cultured in XLCM produce cytokines consistent with the expansion of Th1, Th2, and Th0 subsets, whereas CD8+ T cells cultured in XLCM are cytolytically competent. An interesting feature of T cells cultured in XLCM is the persistence of 5%-10% CD4+CD8+ double-positive T cells in spite of substantial single-positive T cell expansion, suggesting that these cells also proliferate in XLCM. In addition to subsets of TCRalphabeta+ T cells, TCRgammadelta+ T cells are also significantly expanded by XLCM. These results demonstrate that XLCM efficiently expands several functional T cell subsets and provides a means of obtaining selected populations suitable for use in cellular immunotherapy.     

Glycolysis determines dichotomous regulation of T cell subsets in hypoxia

Hypoxia occurs in many pathological conditions, including chronic inflammation and tumors, and is considered to be an inhibitor of T cell function. However, robust T cell responses occur at many hypoxic inflammatory sites, suggesting that functions of some subsets are stimulated under low oxygen conditions. Here, we investigated how hypoxic conditions influence human T cell functions and found that, in contrast to naive and central memory T cells (T_N and T_CM), hypoxia enhances the proliferation, viability, and cytotoxic action of effector memory T cells (T_EM). Enhanced TEM expansion in hypoxia corresponded to high hypoxia-inducible factor 1α (HIF1α) expression and glycolytic activity compared with that observed in T_N and T_CM. We determined that the glycolytic enzyme GAPDH negatively regulates HIF1A expression by binding to adenylate-uridylate–rich elements in the 3′-UTR region of HIF1A mRNA in glycolytically inactive T_N and T_CM. Conversely, active glycolysis with decreased GAPDH availability in T_EM resulted in elevated HIF1α expression. Furthermore, GAPDH overexpression reduced HIF1α expression and impaired proliferation and survival of T cells in hypoxia, indicating that high glycolytic metabolism drives increases in HIF1α to enhance T_EM function during hypoxia. This work demonstrates that glycolytic metabolism regulates the translation of HIF1A to determine T cell responses to hypoxia and implicates GAPDH as a potential mechanism for controlling T cell function in peripheral tissue.     

Longitudinal analysis reveals age-related changes in the T cell receptor repertoire of human T cell subsets

A diverse T cell receptor (TCR) repertoire is essential for protection against a variety of pathogens, and TCR repertoire size is believed to decline with age. However, the precise size of human TCR repertoires, in both total and subsets of T cells, as well as their changes with age, are not fully characterized. We conducted a longitudinal analysis of the human blood TCRα and TCRβ repertoire of CD4⁺ and CD8⁺ T cell subsets using a unique molecular identifier–based (UMI-based) RNA-seq method. Thorough analysis of 1.9 × 10⁸ T cells yielded the lower estimate of TCR repertoire richness in an adult at 3.8 × 10⁸. Alterations of the TCR repertoire with age were observed in all 4 subsets of T cells. The greatest reduction was observed in naive CD8⁺ T cells, while the greatest clonal expansion was in memory CD8⁺ T cells, and the highest increased retention of TCR sequences was in memory CD8⁺ T cells. Our results demonstrated that age-related TCR repertoire attrition is subset specific and more profound for CD8⁺ than CD4⁺ T cells, suggesting that aging has a more profound effect on cytotoxic as opposed to helper T cell functions. This may explain the increased susceptibility of older adults to novel infections.     

Subcellular targets of cisplatin cytotoxicity: An integrated view

Cisplatin is a chemotherapeutic drug widely used against a variety of cancers. Its clinical utility is severely limited by its toxicity, which mainly affects, but is not limited to, the inner ear and renal tubules. Cisplatin toxicity is determined by target tissue and cell accumulation, subcellular handling and trafficking through diverse subcellular structures, and interaction with macromolecules. Cisplatin accumulates and stresses different organelles from which delay signaling is activated, including mitochondria, lysosomes, the endoplasmic reticulum, the nucleus, the cell membrane and cytoskeleton, and can also be found in the cytosol. This article critically summarizes the available information in order to establish the connection among its known subcellular effects in a hierarchical and integrative framework. Cisplatin causes different types of cell death in a concentration-dependent manner. Knowledge of the events and signaling leading to the different phenotypes is also intertwined within the model, within the scope of the potential utility of this information in the improvement of the pharmacotoxicological profile of this drug. Perspectives for the key aspects that need to be addressed by future investigation are also outlined.     

Murine CD4+ T cell subsets defined

We have used two monoclonal anti-murine T cell autoantibodies (SM3G11 and SM6C10) and multi-color immunofluorescence staining to resolve splenic CD4+ cells into four populations. Two of these populations (Fr. I and Fr. III, 35% and 10% of CD4+ cells) show mutually exclusive expression of these determinants and exhibit distinct functions. Fr. III secretes IL-4, but not IL-2 when activated by Con A, and includes memory T cells responsible for secondary antibody formation. In contrast, Fr. I secretes IL-2 but not IL-4 in response to Con A, and does not contribute to the secondary antibody response. Furthermore, these two fractions exhibit differential accessory cell dependence. Whereas Fr. III responds with B cells (and also non-B cells) as accessory cells in Con A-induced activation, Fr. I requires non-B cells. However, we found that many CD4+ cells (Fr. II, 40% of CD4+ cells) express both determinants and are not distinguishable with regard to lymphokine secretion, accessory cell effect, and memory T cell activity. Curiously, the fraction expressing neither determinant (Fr. IV, 10% of CD4+ cells) is unresponsive to experimental conditions used here. We discuss the possible relationships between these T cell subsets and the implications of differential expression of these determinants.     

The biology of ageing arteries. An integrated view

It is suggested that damaged arterial smooth muscle cells (SMC) and altered structural proteins are interpreted as foreign and degraded by the complement system and by macrophages. At the same time growth factors are liberated, stimulating hyperplasia of SMC. In atheromata this proliferation may be monoclonal. The long-lived proteins in the ground substance are glucosylated by Amadori reactions leading to virtually stable compounds and to polymerization. This process is enhanced by high blood sugar and possibly by vitamin B6 deficiency. The proteoglycans adsorb lipoproteins which are transported to macrophages during the reconstruction of the wall. The combined result of all these changes is a thickened and stiff intima with decreased nutritional flow to the cells and decreased transmissibility of macrophages and other cells. In addition to antihyperlipemic treatment, arteriosclerosis prevention should include antihypertensive treatment preferably with calcium blocking or beta blocking agents or both and antidiabetic treatment, but also nutritional measures including the supply of Mg, Vitamins E and B6 and possibly nitrites.     

CD8 and β2-microglobulin-free MHC class I molecules in T cell immunoregulationMHC class I molecules in T cell immunoregulation

Summary Intracellular assembly of MHC class I heavy chains with β₂-microglobulin occurs prior to the expression of the antigen-presenting complex on the cell surface. The association of β₂-microglobulin with newly synthesized class I heavy chains is thought to be a strict prerequisite for their transport to the cell surface. However, MHC class I molecules not associated with β₂-microglobulin (β₂-microglobulin-free class I heavy chains) have been detected on the surface of activated lymphoid cells. These molecules have different conformations. Therefore, their interactions with other membrane proteins and biological functions may be different from those assigned to β₂-microglobulin-associated MHC class I molecules. The two forms of MHC class I molecules on the surface of activated cells can self-associated and also form complexes with distinct proteins. Upon interaction with the appropriate ligands these molecular complexes transduce signals regulating cell activation. The ligand for β₂-microglobulin-free class I heavy chains appears to be soluble CD8. A model is presented describing a novel mechanism of immunoregulation mediated by both soluble and membrane-bound forms of CD8 and β₂-microglobulin-free class I heavy chains.     

2例异体手移植术后受者T细胞亚群与CD3^＋HLA—DR^＋细胞水平的动态观察

目的 研究异体复合组织移植－手移植术后病人外周血T淋巴细胞亚群及CD3^ HLA-DR^ T细水平的动态变化。方法 用流式细胞术测定了2例异体手移植术后不同时间外周血CD3^ 、CD3^ 、CD4^ 、CD3^ 、CD8^ 、CD3^ HLA-DR^ (活化T细胞）细胞百分率，及CD4／CD8比值，以病人 术前一周结果作对照。结果 使用免疫抑制剂后，于术后第1日CD3^ 、CD3^ 、CD4^ 、CD3^ 、CD8^ 、CD3^ HLA-DR^ 细胞水平，CD4／CD8比值都开始降低，以3－5日为最低水平。术后8日，上术指标逐渐回升，至15日后基本趋于平稳，但CD3^ 、CD3^ 、CD4^ 及CD4／CD8比值仍明显低于术前，而CD3^ 、CD8^ 、CD3^ HLA-DR^ 细胞水平则高于术前。结论 异体复合组织－手移植术后病人外周血T淋巴细胞亚群及CD^3 HLA-DR^ 细胞水平的变化与单一组织器官移植（肾移植）术后稳定期的变化一致，也与病人术后的稳定病情相吻合。     

Generation of antigen receptor-specific suppressor T cell clones in man

We have shown previously that CD8+ T cells proliferate upon exposure to autologous, antigen primed CD4+ T cells, and suppress the response of fresh T cells to the priming antigen but not irrelevant antigens. The stimulus and target of suppression in this system appears to be the antigen receptor on the surface of CD4+ cells, rather than the nominal antigen. In the current study, alloantigen primed CD4+ inducer cells and IL-2-containing medium were used to generate clones of suppressor cells from several individuals. The clones inhibited the response of fresh autologous T cells only to the original allogeneic stimulator cell and to stimulator cells that shared HLA-DR antigens with the priming cell. The clones were also genetically restricted, since they inhibited the response of HLA-A,B-compatible but not HLA-A,B-incompatible individuals. The availability of a method for reproducibly generating antigen receptor-specific suppressor T cell clones in vitro should make it possible to clarify the mechanism, whereby such cells are activated and exert their suppressive effect.     

T cell growth factor abrogates concanavalin A-induced suppressor cell function

Concanavalin A (Con-A)-induced suppressor T cells were found to respond to T cell growth factor (TCGF) by proliferation. TCGF abrogated the suppressor activity exerted by these cells on phytohemagglutinin (PHA)- and alloantigen- induced lymphocyte proliferation and on pokeweed mitogen (PWM)-driven immunoglobulin secretion. The Con-A-activated suppressor T cells absorbed the TCGF activity, preincubation of these active suppressor cells with TCGF abolished their suppressor activity and addition of increasing numbers of Con-A-activated T cells reverted the abrogator,/ effect of TCGF. Altogether, these findings suggest that Con-A-induced suppressor T cells exert their function by decreasing the available levels of TCGF. Cyclosporin-A (CYA), which is known to inhibit the expression of receptors for TCGF on T cells, also inhibited the suppressor activity as determined in both indicator systems, namely PHA- or alloantigen-induced DNA synthesis and PWM-induced immunoglobulin synthesis. CYA made Con-A-treated T cells unresponsive to TCGF and unable to absorb the growth factor, supporting the notion that CYA inhibits the expression of TCGF receptors on T cells, a mechanism by which this drug seems to abrogate Con-A-induced suppressor T cell function.