Thymic hormonal activity on human peripheral blood lymphocytes, in vitro. V. Effect on induction of lymphocytotoxicity

Thymic hormonal effect on lymphocytotoxicity induced in vitro and its target specificity were tested using peripheral blood mononuclear cells (PBMC) of healthy subjects. PBMC were treated by the thymic extract TP-1, a similarly prepared spleen extract (SE) or medium only (1 h, 37 degrees C) and then induced to express cytotoxic activity by exposure to allogeneic tumor cells in mixed cultures or by Con A stimulation. The cytotoxicity developed after several days in culture was assayed on 51Cr labelled tumor cells. TP-1 caused a significant mean enhancement of cytotoxicity induced and assayed on Raji lymphoma cells (mean % specific lysis, 31.5 +/- 2.9 without TP-1 and 53.7 +/- 3.6 with TP-1; n = 42; p less than 0.01). The scatter of individual responses to TP-1 was wide, however, and included also some cases of TP-1 induced suppression. Similar wide scatter of TP-1 effects with emphasis on TP-1 induced enhancement was observed with other tumor cell lines or with Con A as inducers. Usually, SE had no effect on induced cytotoxicity. Target selectivity (specificity) of induced cytotoxicity was tested by induction and assay on several tumor cell lines with crossing over, as well as by cold competition assay. When target selectivity was present, it was not masked by TP-1 induced enhancement. Moreover, in some cases, target selectivity became more pronounced after TP-1 treatment. However, TP-1 enhanced also Con A induced non-specific cytotoxicity. No effect of TP-1 on natural killer cell activity of fresh PBMC could be demonstrated. It is suggested that both selective cytotoxicity (T-cell dependent) and non-selective one maybe modulated directly by TP-1 and indirectly by TP-1 modified secondary interactions in culture. This profound regulatory effects could be demonstrated in the PBMC of immune-intact healthy adults.     

Fetuin. In vitro effect on sheep erythrocyte rosette formation with human T lymphocytes.

Peripheral blood lymphocytes from six healthy control subjects were incubated in vitro with fetuin and enumerated for sheep erythrocyte rosette forming T cells. Significant enhancement of rosette-forming T lymphocytes was observed in a dose-related manner. The physical presence of fetuin is not required for this effect. Incubation of lymphocytes with human AB serum has no significant effect on the rosette formation. This enhancing effect of fetuin appears to be secondary to alteration in T lymphocyte surface receptors for sheep erythrocytes.     

Effect of in vitro x-irradiation on human peripheral blood T and B lymphocytes.

The effect of in vitro irradiation with increasing in logarythmic progress X-ray doses on lymphocyte viability and on T and B lymphocyte populations was studied in normal adults, patients with myasthenia gravis and in patients undergoing long-term steroid therapy. Decrease in numbers of lymphocytes carrying T or B lymphocyte surface markers was higher than viable cell loss. The decrease showed no linear correlation with X-ray doses applied, which might reflect the existence of radioresistant T and B lymphocytes. A higher so called early radiosensitivity of B lymphocytes was demonstrated. In patients with myasthenia gravis early radioresistance of T lymphocytes was detected. In patients undergoing long-term steroid therapy, an increase in numbers of cells lacking markers of any of lymphocyte populations was found in parallel with a decrease in T lymphocyte number which, in these patients, showed a higher radiosensitivity.     

Spontaneous rosette formation by lymphocytes. Differential effect of cytochalasin B on thymocytes and thymus-related peripheral blood lymphocytes in the guinea-pig.

In the present investigation the differences in the capacity of thymocytes (Th) and thymus-related peripheral blood lymphocytes (TBL) of the guinea-pig to form spontaneous rosettes with rabbit erythrocytes (RRBC) were further evaluated. Cytochalasin B (CB) inhibited TBL rosette formation but was largely ineffective with respect to Th. This suggests that membrane modulation and microfilament function are requirements for the formation of TBL but not of Th rosettes. A certain critical RRBC receptor density on the lymphocyte may be necessary for a stable rosette. Our results suggest that different RRBC receptor densities on Th and TBL account for the differences in rosette forming capacity of these two cell types. In native Th, the receptor density may be high enough to warrant stable rosette formation. In TBL, however, active membrane movement and perhaps clustering of receptors may be necessary to achieve the local critical receptor density as prerequisite of a stable rosette.     

In vitro radiosensitivity of human T and B lymphocytes evaluated using lymphocyte transformation tests and rosette formation tests.

The influence of irradiation upon human lymphocytes was studied using lymphocyte transformation tests and formation of E and HEAC rosettes. Irradiation was given in vitro using doses between 0 and 50,000 rad. It was shown that blast transformation after stimulation with T-cell stimulating agents (as PHA, PWM, Con.A and PPD) was suppressed by irradiation. The effect of irradiation upon T lymphocytes was also shown in different kinds of MLC experiments. Both the effect of irradiation upon rosetts formation and the influence of irradiation upon already formed rosettes were analyzed. The ability of lymphocytes to form E rosettes was affected after irradiation with 500 rad: there were fewer E rosettes with 3 SRBCs, decrease in total number of E rosettes and more null cells, with no depression of the number of HEAC rosettes formed. Already formed E and HEAC rosettes were totally unaffected of irradiation, and this radioresistance was also observed for 18-hour-old rosettes. The ability to form spontaneous E rosettes was decreased after irradiation of the lymphocytes with 100 rad; increasing doses did not cause further depression, and already formed spontaneous E rosettes were radioresistant. The mechanisms involved in E-rosette formation thus seem to be radiosensitive.     

Inhibitory effect of sheep erythrocyte fragments on rosette formation of human T lymphocytes with sheep red blood cells.

The effect of sheep red blood cells (SRBC) fragments on rosette formation of human peripheral T lymphocytes with SRBC was evaluated on the active and total T-rosette tests. The rosetting capacity of active rosette-forming cells was selectively and nearly completely inhibited by the pretreatment of lymphocytes with SRBC fragments. The decrease in total rosettes by blocking with SRBC fragments was almost parallel to that of active rosettes. SRBC fragments had no inhibitory effect on the rosetting capacity of a lymphocyte population in which active rosette-forming cells were removed by gradient centrifugation. These results suggested that active rosette-forming cells in human T lymphocytes have the receptors of high affinity for SRBC and these receptors readily bind SRBC fragments, resulting in block of rosette formation.     

Enumeration and isolation of human T and B lymphocytes by rosette formation with antibody-coated erythrocytes.

Rosette techniques are presented for the enumeration and separation of both Ig+ T- and Ig- T+ human lymphocytes. In order to enumerate Ig+ cells, the direct immunocytoadhesion technique was employed using human erythrocytes (E) coated with purified anti-kappa or anti-lambda light chain antibodies. Specificity of these rosettes was shown with chronic lymphocytic leukaemias of either the kappa or lambda type. T+ cells were enumerated by a new indirect rosette technique in which the lymphocytes were initially treated with rabbit anti-human thymus cell antiserum followed by direct rosetting with human E coated with purified anti-rabbit light chain antibody. For normal individuals, 24-32% Ig+ T- cells and 65-71% Ig- T+ cells were found among the lymphocytes of peripheral blood as well as tonsils with these rosette methods. The Ficoll-Hypaque method was used to obtain purified Ig- T+ and Ig+ T- cells by removing rosetted Ig+ cells or T+ cells, respectively. The purity of the Ig- T+ cells was indicated by greater than 99% indirect rosetting of cells sensitized with anti-human thymus cell antibody (Ab) and by less than 1% direct rosetting with anti-kappa Ab-E+ anti-lambda Ab-E. The purity of the Ig+ T- cells obtained was indicated by 92-96% direct rosetting with anti-kappa Ab-E+anti-lambda Ab-E and by less than 1% indirect rosetting with anti-human thymus cell antibody. A small percentage of Ig- T- 'null' cells could not be identified by either reagent. Thus, essentially pure Ig- T+ and Ig+ T- cells were readily and efficiently isolated by 'negative selection' thereby lessening the possibility of functional changes that may develop by more extensive manipulation of lymphocytes.     

Content of T and B lymphocytes in healthy human peripheral blood

It was shown by the rosette-formation method that the number of T and B lymphocytes in human blood varies with the time of day and season of the year. The number of T cells reaches a maximum in the morning and the number of B cells in the evening. The relative percentage of B cells is higher in the fall than in winter.Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 872–874, July, 1976.     

5'-nucleotidase of B and T lymphocytes isolated from human peripheral blood.

The ecto-5'-nucleotidase activities of highly purified T and B lymphocytes from human peripheral blood have been investigated using biochemical and histochemical techniques. The enzyme activity of the purified B cells was about 3.5 times that of the T cells. Using a histochemical assay, 21--55% of the B cells stained positively for 5'-nucleotidase, but only 2--22% of the T cells were positive. These results are discussed in relation to the low 5'-nucleotidase activities found on peripheral blood lymphocytes from patients with chronic lymphatic leukaemia and some patients with primary hypogammaglobulinaemia.     

Simultaneous determination of T,B, and mixed rosette-forming lymphocytes in human peripheral blood

Preliminary treatment of erythrocytes in suspension with trypan blue did not affect their ability to take part in the spontaneous rosette formation test, but enabled them to be distinguished when mixed with other erythrocytes after staining with methyl green-pryronine in fixed preparations. The presence of a small subpopulation of lymphocytes binding both types of indicator particles was demonstrated by the use of a mixture of these, erythrocytes with erythrocytes sensitized by antibodies and complement.Department of Immunology and Laboratory of Immunomorphology, Research Center, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR Yu. M. Lopukhin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 6, pp. 714–716, June, 1977.     

T and B lymphocytes in peripheral blood in anesthesiologic personnel.

T and B lymphocytes were determined quantitatively in anesthesiologic personnel by the rosette technique. Percentages of T lymphocytes were diminished, while the lymphatic system of the peripheral blood showed signs of stimulation. The drop in percentages of T lymphocytes was greater in physicians compared with anesthesiologic nurses.     

人外周血T淋巴细胞胀亡现象的观察

目的观察人外周血T淋巴细胞的胀亡现象,探讨建立T细胞胀亡检测方法.方法密度梯度离心法及尼龙棉柱法分离健康成年人外周血T淋巴细胞,分空白组及地塞米松组,培养后观察细胞光镜、荧光镜及电镜形态学,并用流式细胞仪检测胀亡细胞比例变化.结果①人外周血T淋巴细胞经96小时体外培养,可自然出现典型细胞胀亡形态学改变.②经72小时培养,不同浓度地塞米松组(1×10-6、1×10-5、1×10-4、1×10-3 mol/L)T细胞的胀亡率分别为(3.49±0.42)%、(5.17±0.48)%、(8.44±0.72)%、17.93±1.50)%.③在1×10-5mol/L地塞米松作用下,不同培养时间(48、72、96、120小时)T淋巴细胞的胀亡率分别为(0.53±0.10)%、(6.36±0.80)%、(20.60±1.59)%、25.56±1.76)%.结论人外周血T淋巴细胞存在胀亡现象,地塞米松可诱导人外周血T淋巴细胞胀亡.     

Differentiation of human peripheral blood B lymphocytes.

Human B-lymphocyte differentiation was studied by measuring the capacity of such cells, isolated from peripheral blood, to synthesize and secrete Ig after pokeweed stimulation. Results show that a maximum incorporation of [3H]-thymidine took place 2 days before the appearance of detectable Ig-secreting cells. On the 7th day after pokeweed stimulation, when Ig synthesis and secretion are at a maximum, [3H]-thymidine uptake was low. Since inhibition of DNA synthesis 3 days after pokeweed stimulation completely prevents the generation of Ig-secreting plasma cells, initial DNA synthesis is apparently essential before Ig-secreting plasma cells can develop in response to pokeweed stimulation.     

Prednisone increases apoptosis in in vitro activated human peripheral blood T lymphocytes

Glucocorticoid hormones (GCH) regulate, through the apoptotic process, the negative selection of immature T cells in the thymus. Because apoptosis seems to occur also in the maintenance of peripheral tolerance, we have investigated whether GCH may induce apoptosis in human mature lymphocytes. Peripheral blood lymphocytes (PBL) or peripheral CD4⁺ and CD8⁺ T cell subsets were cultured in the presence of phytohaemaglutinin (PHA) or PHA and prednisone (PDN) at 10⁻³-10⁻¹²M concentrations for 72, 96 and 120h. Cell cycle and membrane antigen expression were evaluated by flow cytometry and DNA degradation was detected by agarose gel electrophoresis. PDN blocks PBL growth in the G₁ phase of cell cycle and inhibits both IL-2 receptor (IL-2R) expression and IL-2 secretion. Apoptosis is clearly increased by PDN in PHA-activated human PBL, and the apoptotic effect of PDN is stronger on CD8⁺ than on CD4⁺ T lymphocytes. All these effects are dose- and time-dependent. The addition of exogenous IL-2 did not rescue lymphocytes from PDN-increased apoptosis. These results show that PDN increases apoptosis in mature activated human peripheral blood lymphocytes, suggesting a possible role of GCH in the maintenance of immune tolerance at post-thymic level.     

Rosette formation by human T and B lymphocytes

Human peripheral lymphocytes, identified as T or B cells with a fluorescent anti-globulin serum, were studied in two varieties of rosette formation: (1) with sheep red corpuscles, a phenomenon shown by a large proportion of human lymphocytes and totally different from that observed in the mouse; and (2) with human red cells sensitized with incomplete anti-Rh. Lymphocytes forming sheep cell rosettes were never fluorescent; i.e. they were T cells. 73 % of lymphocytes forming sensitized-cell rosettes were fluorescent B cells. Horse anti-human lymphocyte serum inhibits the first but not the second variety of rosette formation.     

In vitro X-ray irradiation of human peripheral blood T lymphocytes enhances suppressor function

We studied the effect of in vitro X-ray irradiation on human peripheral blood T lymphocytes, with regard to their suppressor activity related to the concanavalin A (Con A)-induced suppressor system. To generate suppressor T lymphocytes, purified human T lymphocytes were incubated for 3 days in the first culture, with or without Con A. These lymphocytes were irradiated with various doses of X-ray before, mid or after the culture. After doing a second culture for 6 days, we measured the suppressive influence of these cells on T lymphocyte proliferation rates stimulated with allogeneic mononuclear cells, and B lymphocyte proliferation rates stimulated with pokeweed mitogen. Irradiation (1,000 rad) of cultures to which Con A had not been added induced much the same level of suppressor activity as seen in the cultures with Con A. The suppressor activity gradually increased with lapse of time from the irradiation to the suppressor cell assay. Suppressor T lymphocytes were resistant to X-ray irradiation and independent of DNA synthesis. On the other hand, irradiation-induced enhancement was minimal in cultures incubated with Con A, regardless of the irradiation time. As irradiation of human peripheral blood T lymphocytes was found to induce a suppressor function in vitro, clinical and experimental applications of irradiation in cases of a suppressed T lymphocyte function may be feasible.     

Comparison of phorbol myristate acetate and phytohaemagglutinin as stimulators of in vitro T lymphocyte colony formation of human peripheral blood lymphocytes. I. Surface markers of colony cells.

Human T lymphocyte colonies were grown in methylcellulose semi-solid cultures in the presence of phytohaemagglutinin (PHA) and/or phorbol myristate acetate (PMA). Surface marker analysis showed lower percentages of OKT3- and OKT4-positive cells in PMA-induced colonies than those in PHA-induced colonies. The percentage of OKIa1-positive cells in PMA-induced colonies was approximately twice that in PHA-induced colonies. The percentage of OKT9-positive cells in PMA-induced colonies was significantly lower than that in PHA-induced colonies. These data suggest that the subsets of PMA-induced colony cells express a more immature phenotype than that of PHA-induced colony cells and that, among PMA-induced colony cells, there are fewer T cells in the proliferative status at the time tested. When 3 X 10(5)/ml monocyte-depleted T cells, at which concentration of seeded cells neither PHA nor PMA could induce colony growth, were cultured in the presence of both PHA and PMA, T cell colony growth was observed. In T cell colonies induced by a combination of PHA and PMA, the percentages of OKT3-, OKT4- and OKT8-positive cells were different from those in colonies induced by either PHA or PMA alone. These results suggest that PMA acts not only as a substitute for monocytes and/or interleukin-1, but may directly affect lymphocyte proliferation induced by a combination of PHA and PMA.