Activation Of Peripheral Mononuclear Cells Research Articles

Soluble interleukin 2 receptors abrogate IL-2 induced activation of peripheral mononuclear cells

Soluble interleukin 2 receptors (sIL-2R) exert a potential role in immunoregulation. We investigated the in vitro effects of sIL-2R on several interleukin 2 (IL-2)-dependent cellular events. Cytotoxicity of human rIL-2-stimulated PBMC against K562 and Daudi was correlated inversely to the concentration of sIL-2R in the culture medium during rIL-2 stimulation. sIL-2R concentrations higher than 4.0 pM produced a significant loss of cytotoxicity ( P < 0.01). The effect of different sIL-2R concentrations added to cultured human PBMC on secondary sIL-2R production was tested by ELISA. Secondary sIL-2R production was abrogated by high initial sIL-2R dosages whereas low initial dosages were followed by a continuing production of secondary sIL-2R after five days of culture. Proliferation of the IL-2-dependent mouse cell line CTLL-2-was suppressed by sIL-2R added to the culture medium in a dose-dependent way. The neutralizing capacity of sIL-2R strongly depended on the initial number of CTLL set in per proliferation assay. In contrast, variation of rIL-2-concentration had no significant effect on reduction of proliferation by sIL-2R. Furthermore, preincubation of sIL-2R with rIL-2 did not enhance growth suppression. These last findings indicate that there is at least no functional interaction between sIL-2R and free IL-2, whereas an interaction of sIL-2R with the membrane-bound receptor for IL-2 seems possible.

Haemopoietic chimaerism: a complication in heterozygote detection tests for inherited defects in cattle

Several observations are documented which illustrate that haemopoietic chimaerism is a potential source of error when using assays of cellular components of blood to determine genotype for inherited defects in cattle. Acidic alpha-glucosidase activity in peripheral mononuclear cells of a twin Brahman bull that had sired calves affected with generalized glycogenosis was similar to that in cells from homozygous normal animals. Activity in fibroblasts from this bull was similar to that in heterozygotes. alpha-mannosidase activity in fibroblasts of a twin Murray Grey bull with low activity in peripheral granulocytes but high activity in plasma was similar to that in animals homozygous normal for alpha-mannosidosis. Normal argininosuccinate synthetase nucleotide sequence was detected in leucocytes from two calves affected with citrullinemia and mutant sequence detected in leucocytes from their homozygous normal co-twins.

Lymphocyte subset distribution and natural killer cell activity in men with idiopathic hypogonadotropic hypogonadism

Sex-related differences in immune responsiveness are mediated at least in part by sex steroid hormones. Lymphocyte subset distribution in peripheral blood and natural killer cell function both have been reported to be under hormonal control. In order to gain more insight into sex steroid hormone action on the immune system, we have measured the lymphocyte subset distribution and natural killer cell activity in 18 men with idiopathic hypogonadotropic hypogonadism before treatment, and after hormonal treatment had normalized plasma testosterone levels. In untreated patients, the mean plasma testosterone concentrations were significantly lower than those in the treated men (3.0 +/- 0.5 nmol/l vs 16 +/- 1.7 nmol/l, p less than 0.001). The percentage of peripheral CD3+ lymphocytes, CD8+ cells, the CD4+/CD8+ ratio, and the natural killer cell activity of peripheral mononuclear cells measured in a 51Cr release assay against target K 562 cells did not differ between patients with idiopathic hypogonadotropic hypogonadism and healthy adults, and most importantly, did not change during hormonal treatment which normalized plasma testosterone levels in the patients. In contrast, the percentage of peripheral CD4+ cells was significantly higher in untreated patients compared with normal adult subjects or patients with idiopathic hypogonadotropic hypogonadism after hormonal treatment that resulted in normal plasma testosterone levels (53 +/- 2 vs 47 +/ 2, p less than 0.05). It should be noted that the percentage of peripheral CD16+ cells was significantly lower in untreated men with low plasma testosterone levels than in normal controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of Pregnancy on Dipeptidyl Peptidase IV Activity (CD 26 Leukocyte Differentiation Antigen) of Circulating Lymphocytes

Dipeptidyl peptidase IV (CD 26 leukocyte differentiation antigen) is an enzymic surface marker of a human T lymphocyte subpopulation which has been shown to be associated with their capacity to produce large amounts of interleukin 2 and proliferate strongly in response to mitogenic stimulation. The peptidase activity on the surface of purified human peripheral mononuclear cells was determined spectrophotometrically with the substrate glycyl-L-proline-4-nitroanilide. The peripheral mononuclear cells of pregnant women exhibited depressed mean dipeptidyl peptidase IV activity when compared with the activity of peripheral mononuclear cells from non-pregnant or male individuals. The gestational age (7 to 20 weeks) of the pregnant collective had no effects on peptidase levels. Women taking oral contraceptives had a slightly lower mean activity than the non-pregnant group not using contraceptives. Thus, reduced dipeptidyl peptidase IV activity of peripheral mononuclear cells might reflect impairement of cellular immunity during pregnancy.

Die Rolle der Interferone beim Neuroblastom - Teil 2: Immunmodulatorische Effekte

The role of Interferon-gamma (IFN-gamma) in the immunotherapy of neuroblastoma was investigated. In vitro experiments showed that IFN-gamma augments the cytotoxicity of Natural Killer (NK) cells and of interleukin 2 (IL-2)-activated NK (LAK) cells against neuroblastoma target cells. Incubation of the neuroblastoma cells with IFN-gamma resulted in an increased susceptibility of these target cells to NK and LAK cells. Additionally, the IFN-gamma-treated neuroblastoma cells showed an increased susceptibility to the antibody-dependent cellular cytotoxicity (ADCC). In patients who have been treated with continuous infusions of IL-2, IL-2-induced secretion of IFN-gamma was detected by measuring the elevation of the 2-5 A synthetase activity in peripheral mononuclear cells or the 2-5 A oligoadenylates in the serum, although IFN-gamma itself was not detectable. From these results we conclude that IFN-gamma may play an important role in the immunotherapy of neuroblastoma in combination with IL-2 and/or with monoclonal antibodies.

Induced Proteins in Human Peripheral Mononuclear Cells Over a Range of Clinically Tolerable Doses of Interferon-γ

This study assessed biologic response modification at three different dose levels (0.15, 1.5, and 15 mg/m2) of interferon-gamma (IFN-gamma) administered by intravenous bolus three times weekly. A final total of 24 patients were evaluable. Dose-limiting toxicity occurred at the highest dose level (15 mg/m2) and included fatigue, leukopenia, and hepatotoxicity. Evaluation of biologic response modification included assessment of 2',5'-oligoadenylate (2-5A) synthetase activity in peripheral mononuclear cells, measurement of serum beta 2-microglobulin and expression of beta 2-microglobulin on monocytes, measurement of monocyte HLA Class II expression (HLA-DR, HLA-DQ), and measurement of hydrogen peroxide generation by monocytes 24 h after the first and fourth IFN-gamma treatments. Significant increases (p less than 0.05) from baseline were seen at 24 h with all parameters except H2O2 generation. Except for enhancement of HLA-DR, even the lowest dose (0.15 mg/m2) augmented synthesis of 2-5A synthetase and HLA proteins. A dose-response effect was noted for changes in serum and monocyte beta 2-microglobulin levels but not for 2-5A synthetase levels or HLA Class II antigen expression on monocytes. After 4 doses administered over 9 days, most parameters remained increased when compared to pretreatment, but were not further enhanced when compared with levels attained after the first dose. The results of this study document the efficacy of IFN-gamma for biological activation over a wide dose range and are consistent with the postulate that immunoregulatory effects of biological therapeutics can be obtained in man at doses substantially less than those that are maximally tolerated. Further documentation of biologic response parameters by IFN-gamma at low doses will be necessary to determine the importance of biologic activation in relation to antitumor activity.

In vitro interferon producing activity of peripheral mononuclear cells in patients with chronic liver disease.

Interferon-gamma (IFN-gamma) was induced from a human peripheral mononuclear fraction by incubation with a streptococcal preparation stabilized with penicillin G (OK432). This IFN-gamma-producing activity was significantly reduced in patients with chronic hepatitis and hepatocellular carcinoma. In patients with liver cirrhosis it was also reduced but not significantly. Serum hepatitis B virus DNA and skin tests for the purified protein derivative of tuberculin, phytohemagglutinin-P and a polysaccharide fraction prepared from streptococcus pyogenes Su strain were determined to have no significant relation to this IFN-gamma-producing activity. Although the addition of interleukin 2 (IL-2) to the culture medium enhanced the IFN-gamma-producing activity, there was no difference in this enhancement between normal control and chronic hepatitis. Therefore reduction of the IFN-gamma-producing activity observed in chronic hepatitis seems to be caused by a decreased number of IFN-gamma-producing activity cells or hypofunction of these cells or both. Since HBeAg became negative in patients whose IFN-gamma-producing activity was increased by the administration of the immunopotentiator OK432 or IFN-beta, the IFN-producing system in the patients with B type hepatitis may contribute to the elimination of HBV. Adenine arabinoside suppressed IFN-gamma-producing activity both in vivo and in vitro.

New observations regarding killing of fibroblasts infected with herpes simplex virus: cooperation between elutable factor and peripheral mononuclear cells.

With a standard chromium release assay, natural killing (NK) activity of peripheral mononuclear cells (PMCs) from 28 individuals was compared based on the ability of sera to support antibody-dependent cell-mediated cytotoxicity (ADCC) for cells infected with herpes simplex virus (HSV). PMCs from all 20 individuals whose sera produced ADCC were capable of killing HSV-infected cells compared with none of the PMCs from the eight individuals whose sera did not produce ADCC (mean specific release, 33.2% vs. 6.8%). Results could not be explained by contaminating serum in the assay or by ineffective NK by the PMCs from the eight negative subjects because many of them killed the k562 myeloid cell line as effectively as PMCs from other individuals. In addition, NK could be eliminated by preincubation of effector cells at 37 C, and the capacity to kill by PMCs could be reconstituted by incubation in serum. Killing was more a function of source of serum rather than source of cells.

Roles of HTLV-I p19 and natural antibody to HTLV-I in host immune responses.

Since the discovery of human T cell leukemia/lymphoma virus type I (HTLV-I) [5], the immune status of HTLV-I- infected hosts, including patients with adult T cell leukemia (ATL), has not yet been sufficiently investigated [2–4]. As the first step in this kind of study, we have studied the nonspecific activity of peripheral mononuclear cells (PMNC) from ATL patients and seropositive HTLV-I carriers and therole of HTLV-I p19 antigen and HTLV-I-producing cell surface antigens in the host immune responses to HTLV-I.KeywordsNatural Killer ActivityComplement SourceDucing CellNonspecific Immune ActivitySeronegative Healthy DonorThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Acting mechanisms of lentinan in human—II. Enhancement of non-specific cell-mediated cytotoxicity as an interferon inducer

The immunopotentiator “Lentinan” augmented the cell-mediated cytotoxicity in humans. (a) The activation of killer T cells by the mixed lymphocyte culture was accelerated only when responder cells were mixed with both a suboptimum number of stimulator cells and Lentinan. (b) The interferon level in the peripheral blood circulation of cancer patients was elevated in 12 h following Lentinan administration, and natural killer activity of peripheral mononuclear cells was enhanced in 48 h. These data indicate that Lentinan favorably affects the host defence mechanisms of man.

Similar disturbances in B cell activity and regulatory T cell function in Henoch-Schönlein purpura and systemic lupus erythematosus.

The immunoglobulin synthesizing activities of peripheral mononuclear cells (MNC) from five patients with Henoch-Schonlein purpura (HSP) and eight patients with active systemic lupus erythematosus (SLE) were compared. Cumulative amounts of IgM, IgG, and IgA synthesized and secreted by unstimulated and PWM-stimulated patient cells over a 12-day period were determied in a solid-phase radioimmunoassay. In unstimulated control cultures mean rates of IgM, IgG, and IgA synthesis were less than 250 ng/ml. The synthetic activities of patient MNC were markedly increased. In HSP cultures IgA was the major immunoglobulin class produced (2810 x/divide 1.33 ng/ml) followed by IgG (1754 x/divide 1.32 ng/ml) and IgM (404 x/divide 1.16 ng/ml). In SLE cultures IgA and IgG syntheses were equally elevated (4427 x/divide 1.20 and 4438 x/divide 1.49 ng/ml, respectively) whereas IgM synthesis averaged 967 x/divide 1.66 ng/ml. PWM stimulation of pateient MNC caused a sharp decline in the synthesis of all three immunoglobulin classes. After T cell depletion B cell-enriched fractions from HSP and SLE patients maintained high levels of IgA and IgG synthesis that were inhibited by PWM and by normal allogeneic but not autologous T cells. In PWM-stimulted co-cultures, patient T cells nonspecifically suppressed the synthetic activities of autologous and control Bmore » cells. in contrast patient B cells achieved normal levels of immunoglobulin synthesis when cultured with control T cells plus PWM. In longitudinal studies patient B and T cell disturbances persisted despite clinical improvement.« less

Inactivation of S-adenosylhomocysteine hydrolase during adenine arabinoside therapy.

To assess for possible inhibition of cellular transmethylation during adenine arabinoside (ara-A) therapy, S-adenosylhomocysteine hydrolase activity was analyzed in 10 patients with chronic hepatitis B virus infection. In six patients receiving ara-A, enzyme activity was suppressed to 0-2% of control erythrocyte enzyme activity. This decrease in enzyme activity was evident within 4 h of starting the drug infusion and continued for 7 d after cessation of therapy. S-adenosylhomocysteine hydrolase activity of peripheral mononuclear cells was also measured in two patients receiving ara-A. Suppression to as low as 3.5% of pretreatment levels was found; however, marked fluctuations with partial return of enzyme activity during therapy was also observed in mononuclear cells. Inhibition of an enzyme involved in transmethylation reactions was observed in patients during ara-A therapy. This could contribute to the side effects and antiviral properties of ara-A.