Tμ Cells Research Articles

Functional activities of enriched Fc receptor bearing T lymphocytes in Hodgkin's disease.

Our earlier studies have demonstrated that the peripheral blood mononuclear cells (PBMNC) of patients with Hodgkin's disease (HD) have reduced percentage of T mu cells and increased percentage of T gamma cells, while the splenic MNC showed the reversed proportions. In this paper, the functional abilities of subsets with these phenotypes have been investigated. T gamma and T mu cells were enriched from theophylline-sensitive and -resistant populations of lymphocytes obtained from PBMNC and splenic MNC of untreated HD patients and normal healthy donors. The effect of addition of these enriched populations on PHA and mixed leukocyte culture (MLC) responses of corresponding autologous MNC has been studied. The results showed that both PHA and MLC responses of normal as well as of HD lymphocytes could be suppressed by T gamma cells, while T mu cells failed to show an appreciable helper activity. The T gamma population in HD, therefore, appears to maintain suppressor function, thereby influencing the peripheral blood T cell responses.

Studies on the lymphocytic subpopulations in acute non-lymphocytic leukemia.

The amount of T, B, Tγ as well as Tμ cells and the activity of antibody-dependent cellular cytotoxicity (ADCC) in the peripheral blood were studied in 40 cases of acute non-lymphocytic leukemia. The results demonstrated that the T cells decreased and the Tγ cells increased significantly in the acute stage, and both of them were of normal value again in complete remission; while the B cells and Tμ cells decreased in number and the ADCC activity also decreased before and after treatment as compared with the condition in normal individuals. The possible mechanism of these variations is discussed.

T Cell Subset and Steroid Sensitivity in Idiopathic Nephrotic Syndrome in Children

AbstractThe relationship between T cell subset of peripheral blood lymphocytes and steroid sensitivity was studied in children with idiopathic nephrotic syndrome (INS). The subjects were 28 INS children, aged 2 to 16 years. T cells bearing receptors for IgG (Tγ) were identified by double rosette assay with sheep erythrocytes and IgG‐sensitized ox erythrocytes. T cells bearing receptors for IgM (Tμ) were identified by IgM‐sensitized ox erythrocytes rosette assay in purified T cells after incubating overnight.In steroid sensitive INS children, decreased numbers of Tγ cells and increased numbers of Tμ cells in onset or relapse were found and they were normalized with corticosteroid administration. Tγ cells of steroid nonsensitive INS children remained decreased even after steroid therapy.Tγ cells have been suggested to be, at least in part, suppressor T cells. Alteration of peripheral blood Tμ cells in this observation therefore may suggest the abnormality of suppressor T cells in INS children.

Dynamics of T-suppressor and T-helper lymphocytes and haemolytic plaque-forming cells during normal pregnancy in the sow

Tγ and Tμ lymphocytes and haemolytic plaque-forming cells (PFC) were quantitatively determined in peripheral blood and uterine draining lymph nodes (DLN) from 36 nonpregnant and 45 pregnant sows. A considerable increase in the number of Tγ cells occurred both in the blood and the DLN during pregnancy ( P < 0.001). This increase was higher at the beginning of pregnancy (20th–40th day) and lower at the end (80th–110th day). No significant quantitative changes were found in Tμ cells. During pregnancy there was a marked drop in the number of cells in the peripheral blood manifesting direct erythrocytolytic activity (DECA), as well as of haemolysin-producing cells.

Human T-cell subset changes during culture

When human peripheral blood lymphocytes (PBL) are cultured with either concanavalin A (Con A)-treated or control autologous T lymphocytes, the mitogenic responses of the PBL co-cultured with Con A-treated cells are much lower. We have investigated the cell surface receptor changes during culture of T cells with and without mitogen in an attempt to explain this differential regulatory phenomenon. We present data here which show that human T cells cultured in complete medium alone gain helper cells with time. Con A-treated T cells are known to lose helper cells during culture. Erythrocyte rosette-purified T cells were cultured with or without Con A for 84 h and the numbers of cells with receptors for the Fc regions of either IgM (Tμ) or IgG (Tγ) were enumerated daily. Tμ cells have been associated with helper activity while Tγ cells have predominantly suppressor activity. Treatment with 10 μg/ml of Con A decreased Tμ by approximately 50%. Untreated cells, however, showed significant increases in Tμ (44 ± 30.5% in twelve individuals). The great variance in Tμ increases is due to the fact that individuals having higher initial Tμ values showed smaller increases. These changes probably represent the gain or loss of receptors because total cell numbers did not change. There was no significant change in the number of Tγ cells in either control or Con A-treated cultures during the same 84 h period.

Investigation of T gamma cells and T mu cells in peripheral blood of children with different types of viral hepatitis.

Peripheral erythrocyte rosette-forming cells (ERFC), Tγ cell and Tμ cell counts were studied in 141 children with different types of viral hepatitis and in 65 healthy children as control. The results showed variations not only in total number of ERFC, but also in Tγ cells and Tμ cells in different types of viral hepatitis. It was also found that determination of Tγ cell percentage may be of value in diagnosing the condition of the diseases, and determination of Tγ cell and Tγ/Tμ ratio may be of value in estimating the prognosis. The possible mechanism of variations in ERFC, Tγ cells and Tμ cells is discussed.

T‐cell functional abnormality in B‐chronic lymphocytic leukaemia: evidence of a defect of the T‐helper subset

Summary. The helper and suppressor capacity of T, Tμ (T nonγ) and Tγ cells was assessed in a group of patients with B‐cell chronic lymphocytic leukaemia (B‐CLL) in a pokeweed mitogen (PWM) stimulated system. The enriched T‐cells (E‐rosette positive) from all B‐CLL cases showed a reduced capacity to induce the differentiation of normal B‐lymphocytes compared with normal T‐cells (P&lt;0·005). After enrichment of the Tμ cells, the helper/inducer capacity was still significantly depressed compared with the same fraction from normal controls (P&lt;0·01). On the other hand, enriched Tγ cells from B‐CLL were effective in suppressing the differentiation of normal B‐lymphocytes to a similar degree as normal Tγ cells. These findings are indicative of a deficient T‐cell helper function in B‐CLL, which appears to be unrelated to the clinical stage of the disease. The fractionation experiments suggest that this functional impairment is not only due to the abnormal T‐cell subset distribution seen in the majority of cases, but point to a possible intrinsic defect within the Tμ cell population.

Modulating Effects of Enzymes on Tγ and Tµ Cells in Patients with Atopic Dermatitis

Ten patients with moderate to severe atopic dermatitis had increased levels of IgE in the blood and a reduced level of T cells with Fc receptors for IgG (T gamma). After pronase and trypsin digestion of Fc receptors, cultured T cells regenerated the Fc receptors, but preserved the difference between patients and controls. Neuraminidase treatment increased the T gamma-cell level in both patients and controls. Serum from patients with atopic dermatitis could not reduce the T gamma-cell expression in the controls. With regard to Fc receptors, no qualitative difference was observed between patients and controls, but a genuine quantitative difference accounts for the observed reduction of T gamma cells in blood.

Low percentage of Tμ cells in amyotrophic lateral sclerosis

The percentage of Tμ cells in amyotrophic lateral sclerosis patients is markedly reduced. The Tγ population appears normal.

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Peripheral blood and regional lymph node mononuclear cells from 43 untreated patients with breast cancer were analyzed for the proportions of total T-cells and T-cells with receptors for the Fc portion of IgM (T mu), IgG (T gamma), or IgA (T alpha). Proportions of total T-cells and T mu cells both in peripheral blood and lymph nodes from breast cancer patients were comparable to those from health controls. The proportion of T gamma cells, however, was significantly (P less than 0.01) increased in the peripheral blood and lymph nodes from breast cancer patients as compared to that from controls. The proportion of T alpha in the peripheral blood was comparable; however, when compared to the number of T alpha cells in control lymph nodes, T alpha cells were increased (P less than 0.025) in the regional lymph nodes from patients with breast cancer. When data on the proportions of T-cells and T-cell subsets were analyzed according to the presence or absence of metastatic disease in the regional lymph nodes, the proportion of T gamma cells was significantly (P less than 0.025) higher in the peripheral blood from patients with metastatic disease than in patients with nonmetastatic disease. This study demonstrates an abnormality of T-cell subsets in the peripheral blood and the regional lymph nodes from patients with breast cancer. The significance of these observations is discussed.

Characterization of canine T-lymphocyte subpopulations: The detection of Tμ and Tγ lymphocytes with homologous and heterologous immunoglobulins and the requirements for Fc receptor expression

Erythrocyte antibody (EA) rosette techniques employing sheep red blood cells sensitized with canine (homologous) and rabbit (heterologous) IgM and IgG antibodies were used to determine the number of cells with Fc receptors for IgM (Tμ) and IgG (Tγ) among T lymphocytes isolated from peripheral blood and lymph nodes of dogs. The percentages of Tμ and Tγ lymphocytes detected were found to be independent of the species origin of sensitizing antibody. Among peripheral blood T lymphocytes there were 53.0 ± 2.7% Tμ cells and 18.4 ± 3.6% Tγ cells. T lymphocytes obtained from lymph nodes were 62.1 ± 5.4% Tγ and 15.7 ± 2.6% Tγ. The number of Tμ cells detected increased from 20.0% when freshly isolated to 49.1 ± 4.1% after in vitro culture for 2–16 hr. The expression of the Fc-μ receptor in culture was inhibited by cycloheximide, demonstrating a requirement for active protein synthesis. In contrast, the number of Tγ lymphocytes detected did not vary between freshly isolated cells and those which had been cultured for 16 hr. Expression of the Fc-γ receptor during this time period was not inhibited by cycloheximide.

In-vitro-induced human T cells cytotoxic against herpes-simplex-virus-infected targets: Modulation by theophylline of the induction and effector stages

We have shown in previous studies that the cytotoxic effector cells in in-vitro-induced cytotoxicity against herpes-simplex-virus-infected targets are principally Tγ cells and that they derive from theophylline-resistant Tμ cells. In the present work, we studied the effect of theophylline on the induction and expression of cytotoxic activity in T-cell subsets. When T cells were prefractionated before the induction phase, the theophylline-resistant (THr) subset, as determined by E-rosetting, was unaffected by the presence of theophylline during sensitization, whereas Tμ and unfractionated T cells were inhibited. On the other hand, when theophylline was present during the cytotoxicity assay, all T-cell subsets similarly affected. Studies of kinetics revealed that a short preincubation with the drug had an enhancing rather than an inhibitory effect on both the proportions of Tγ and Thr and on their cytotoxic activity at 3 days.

Regulation of Human Blood Erythroid Burst-Forming Unit (BFU-E) Proliferation by T-Lymphocyte Subpopulations Defined by Fc Receptors and Monoclonal Antibodies

To determine whether normal T-cell subpopulations influence human blood BFU-E proliferation variably, sheep erythrocyte rosettable cells (unseparated T cells) were fractionated into subpopulations based on their differential binding to IgM (Tμ cells) or IgG-coated ox erythrocytes (Tγ cells). For comparative purposes, T cells, Tγ cells, and T cells depleted of Tγ cells (T-non-γ cells) were further characterized by their reaction with the OK panel of monoclonal antibodies (OKT3, OKT4, OKT8, OKM1). Quantities of 2.0 × 105 Tμ, Tγ, or T-non-γ cells were mixed with 2.0 × 106 autologous BFU-E-enriched null cells in a methyl-cellulose culture system with 2.0 IU erythropoietin. Tμ cells or T-non-γ cells consistently increased BFU-E numbers above that observed with either unseparated T cells or Tγ cells (p

Detection of guinea pig Tμ and Tγ cells by a double rosette assay

By a rosette assay with ox red blood cells (ORBC) sensitised with rabbit IgM and IgG antibodies (EAμ and EAγ), receptors for IgM (Fcμ-R) and IgG (Fcγ-R) on the surface of guinea pig lymphocytes in the different lymphoid organs were demonstrated. A double rosette assay with rabbit erythrocytes (RRBC) and EAμ or EAγ for detection of T cells with Fcμ-R (Tμ) or Fcγ-R (Tγ) was also developed. Fcμ-R was detected on 40.1%, 48.7%, 35.0% and less than 1% of peripheral blood, lymph node, spleen and thymus cells respectively. By a double rosette assay with RRBC and EAμ, approximately 30% of peripheral blood, lymph node and spleen T cells were identified as Tμ cells. Tγ cells as revealed by a double rosette of RRBC and EAγ were found to be 3% and 5% respectively of peripheral blood and lymph node T cells, whereas much higher numbers of T cells in the spleen (32.7) were identified as Tγ cells. This double rosette assay of Tμ and Tγ cells in the peripheral blood of guinea pigs which had received prednisolone showed that the proportion of Tμ cells decreased early after drug administration and that Tγ cells increased in number. Thus the methods provide a useful means of detecting Tμ and Tγ cells in guinea pig. This assay system for Tμ and Tγ cells in guinea pigs should be useful for studies of their variation or functional significance in the immune response.

Monocyte-produced prostaglandin induces Fcγ receptor expression on human T cells

Incubation of human T cells for 18 hr with prostaglandin E 2 (PGE 2 3 × 10 −6 M) causes a slight but significant increase in the percentage of Tγ cells and a reduction in Tμ cells. When PGE was added to “non-Tγ” cells, the increase in the percentage of Tγ cells was more marked (from 1.5% Tγ without PGE to 11% Tγ with PGE 2, P < 0.001). Supernates from cultures of human monocytes also caused an increase in Tγ cells (10% Tγ without supernate to 18% with supernate, P < 0.01), and this increase was blocked if the monocytes were cultured with indomethacin, a prostaglandin synthetase inhibitor (9% Tγ cells). Thus, monocytes may regulate Fcγ receptors on T cells via PGE 2 production.

Effect of therapy on T cell subpopulations in patients with chronic lymphocytic leukemia

We have previously demonstrated functional and quantitative imbalances in two human thymic (T) cell subpopulations. Tγ and Tμ, in chronic lymphocytic leukemia (CLL) patients. Serial evaluations of the numbers of Tγ and Tμ subsets in CLL were performed in order to delineate more completely the patterns of T cell abnormalities. Two groups of CLL patients were studied: (1) previously untreated (n = 3) and (II) stable CLL on chemotherapy (n = 12). In Group I, two of three patients had significantly increased percentages of Tγ cells (mean ± S.E.M. = 57 ± 5 vs 18 ± 2 for controls). There was defective in vitro appearance of Tμ cells in both groups. In Group II, repeated studies of T cell subsets revealed persistently elevated Tγ cells despite various modes of oral chemotherapy. In three CLL patients who required splenectomy a dramatic decrease in the percentages of Tγ, cells was noted post-splenectomy (51 ± 3 to 15 ± 3). In all cases the spleen was diffusely involved with CLL. These findings indicate: (1) abnormalities of T cell subsets are present early in CLL. (2) chemotherapy does not affect the levels of Tγ cells in stable patients and (3) removal of infiltrated CLL spleens results in a dramatic decrease in the proportion of Tγ cells. This latter finding plus the increase in Tγ cells in progressive disease post-splenectomy suggest Tγ cells may be an important determinant of the course of CLL.

Imbalances in T-cell subpopulations in myasthenia gravis

Distributions of peripheral blood lymphocyte subpopulations and T-cell subsets were studied in 38 patients with myasthenia gravis (MG) and 23 healthy controls. T cells were detected by rosette formation with sheep red blood cells and B cells with erythrocyte-antibody-complement (EAC) complexes. Tμ cells were identified by rosette formation of T cells with Ox RBC-IgM complexes, and Tγ cells with Ox RBC-IgG complexes. The means of total lymphocyte count and active T cell percentage were marginally significantly lower in MG patients than in normal controls (0.05 < P < 0.1). The mean percentage of Tμ cells was higher in MG patients than in controls (50.2 ± 11.8% vs. 38.5 ± 15.3%, P < 0.01), whereas that of Tγ cells in the former was lower than that in the latter (20.4 ± 7.1% vs. 27.6 ± 6.2%, P < 0.001). Thus, the loss of regulatory suppressor T cells and the increase of helper T cells in the patients are in favour of regarding MG as an autoimmune disease. The fact that the percentage of Tγ cells was significantly decreased in MG patients after autologus serum incubation, and that no such a phenomenon was seen in normal controls, may suggest a possible role of serum factors in the pathogenesis of MG.

A TH 2− helper T-cell subset and the Tμ cell population: A comparison

The correspondence between the Fc markers and the TH 2 − markers on T cells was studied utilizing an autoantibody to a TH 2 − T-cell subset. This antibody was obtained from a patient with acquired agammaglobulinemia. Lymphocytotoxicity studies and analysis by fluorescence-activated cell sorting show that Tμ cells are enriched in the TH 2 − helper T cell subset defined by the autoantibody.

Detection of Fc-receptor-bearing human lymphocytes. The majority of Tμ cells carry HLA-DR antigens

The Fc receptors of peripheral blood mononuclear cells were studied. The cells detected with anti-Rh Ripley-coated erythrocytes (EA Hu) were the same as those detected with rabbit IgG-coated ox erythrocytes (EA Ra), since depletion of EA-RFC with one system caused an almost complete removal of EA-RFC as detected with both systems. For the isolation of Fc-receptor-bearing T lymphocytes (Tγ and Tμ cells) untreated, AET-treated, and neuraminidase-treated sheep red blood cells were equally good. The effect of anti-HLA-DR antibodies and anti- β 2 microglobulin (anti- β 2m) antibodies on EA-rosette formation was also studied. Anti-HLA-DR antibodies completely inhibited EA IgM-rosette formation of T lymphocytes, whereas no inhibition of EA IgG-rosette formation was observed in any mononuclear cell population. Anti- β 2m antibodies completely inhibited both EA IgM- as well as EA IgG-rosette formation. Less than 5% of freshly isolated T lymphocytes formed EA IgM rosettes and were HLA-DR positive. In contrast approximately 50% of T lymphocytes formed EA IgM rosettes and were HLA-DR positive after overnight incubation. More than 90% of the Tμ cells were HLA-DR positive. Thus, overnight cultivation of T lymphocytes induce expression of HLA-DR antigens along with the Fcμ receptors. This is first report of HLA-DR antigens detected on the majority of nonstimulated human T cells.

Separation of human bone marrow cell populations by density gradient electrophoresis: Differential mobilities of myeloid (CFU-C), monocytoid, and lymphoid cells

Human bone marrow cells from normal donors (purified by centrifugation on Ficoll-Hypaque density cushion) were separated by density gradient electrophoresis, on the basis of their surface charge. The separated cell fractions were analyzed by morphology, surface markers, and functional tests. Morphological examination revealed that immature cells of myeloid and erythroid lineage were significantly enriched in the high-mobility fractions, whereas mature cells in general, e.g., small lymphocytes, monocytes and granulocytes (few) were highly enriched in the low-mobility fractions. Ripley rosette-forming cells, as well as complement receptor and Fc (IgG)-receptor-bearing lymphocytes were relatively enriched in the high-mobility fractions, although they were present in small proportions and in the rest of the fractions. E-rosette-forming cells were enriched in the intermediate- and low-mobility fractions. T cells with Fc receptors for IgM (Tμ cells), determined by a double-rosetting technique, were found to be enriched in the intermediate-mobility fractions. In contrast T cells with Fc receptors for IgG (Tγ cells) were significantly enriched in the low-mobility fractions. Cells in the intermediate-mobility fractions (Tμ enriched) responded by proliferation to mitogens and to allogeneic cells in mixed lymphocyte culture. Cells in the very high or very low (Tγ enriched) mobility fractions responded poorly. Colony-forming units in vitro (CFU-C), determined using either the human leukocyte feeder or the placental CSA culture systems, were found to be significantly enriched in the high-mobility fractions. Low-mobility fractions were devoid of CFU-C. These studies demonstrate that density gradient electrophoresis can be successfully applied for the separation of human bone marrow cells of different lineage and studies of their functional properties.