Proliferation Of Human Blood Lymphocytes Research Articles

Cytotoxic Effects of Pistacia khinjuk Seed Extracts on Different Cell Lines and its Mitogenic Effects on Blood Lymphocyte In Vitro

Reports indicated that extract Pistacia khinjuk has anti-inflammatory, antipyretic, antibacterial, and antiviral, in treating of diarrhea and throat infections and has hepatoprotective effects against acetaminophen and carbon tetrachloride. This study was undertaken to investigate the possible cytotoxic effects of methanolic and aqueous seeds extract of P. khinjuk on different tumors (rhabdomyosarcoma [RD] and murine mammary adenocarcinoma [Ahmed-Mohammed-Nahi-2003 (AMN-3)]) and normal cell lines (murine fibroblast) and its mitogenic effects on blood lymphocytes. The cytotoxic effects of P. khinjuk seed extracts were evaluated on two tumor cell lines, RD and murine mammary adenocarcinoma (AMN-3) and one normal cell line, murine fibroblast (L20B). Moreover, the mitogenic effects of the plant extract were studied, on human blood lymphocytes. Both methanolic and aqueous seed extracts of P. khinjuk significantly induced tumor cell lines and the normal cell line proliferation, especially in highest concentrations. The results show that the extracts induced significant increases in human blood lymphocyte proliferation at 72 h. This activity of plant extracts recommends it as a good mitogenic agent in researches; in conclusion, seed extracts of P. khinjuk induced proliferation of all tested cell lines. High concentrations of both aqueous and methanolic seed extracts of P. khinjuk showed mitogenic effects.

Methoxylated Flavones from Salvia Mirzayanii Rech. f. and Esfand with Immunosuppressive Properties.

Aerial parts of Salvia Mirzayanii was extracted with methanol. Methanol extract was suspended in water and defatted with petroleum ether. The defatted part was then partitioned between ethyl acetate and water. The ethyl acetate partition was chromatographed on a silica gel column to afford several fractions. Lymphocyte proliferation inhibitory assay of the resulted fractions was compared in-vitro and the fraction with more immunosuppressive activity was subjected to more purification to yield three methoxylated flavones: 5,7-dihydroxy,6,4'- dimethoxyflavone(1), 5-hydroxy,6,7,3',4'-tetramethoxyflavone(2) and 5,3'-dihydroxy,6,7,4'- trimethoxyflavone (3). Compounds 2 and 3 potently suppressed the proliferation of human blood lymphocytes with IC50 values of 1.3 ± 0.04 μg/mL and 1.3 ± 0.21 μg/mL in comparison with prednisolone as one of the lymphocyte suppressor drugs (IC50=1.45 ± 0.6 μg/mL). In phagocyte chemiluminescence assay, compounds 1 and 3 in peripheral mononuclear cells (PMNCs) exerted suppressive moderate activity against ROS with IC50 of 55.3 ± 0.4 and 36.2 ± 0.7 μg/mL, respectively, while compound 2 showed weak activity with IC50 values more than 100 μg/mL. In conclusion, compounds 2 and 3 have a similar suppressive effect more than compound 1 on PHA-activated lymphocyte proliferation, which might be because of their C-3' oxidation pattern of ring B. It is indicated that the presence of 3'-OH or 3'-OMe in flavone ring B, caused more anti-proliferation activity than 3'-H. Oxidative burst assay showed more activity for compound 1 which is less methoxylated than others. It also showed more activity for compounds 3 than 2, which differ only in 3'-OH instead of 3'-OMe.

Setae from larvae of the northern processionary moth (Thaumetopoea pinivora, TP) stimulate proliferation of human blood lymphocytes in vitro.

Larvae of the Northern pine processionary moth (Thaumetopoea pinivora, TP) carry microscopic needles (setae), which by penetrating skin and mucous membranes, may cause inflammatory/immune derived symptoms in man. In the present study the stimulatory effects of setae on human blood lymphocytes in vitro was investigated. Blood mononuclear cells were separated from venous blood or buffy coat of ten healthy individuals, six previously exposed to setae and four with no known exposure. Lymphoproliferation was measured as uptake of 3H-thymidine. Setae were prepared from TP larvae. Setae and saline setae extracts stimulated proliferation of T-lymphocytes in the presence of monocytic cells. Stimulation was pronounced in cells from persons who had been exposed to setae, and weak in cells from non-exposed donors. Chitin also induced lymphocyte proliferation in most donors, but to a lesser extent and independently of donor's previous exposure to setae. In conclusion, setae contain molecules that in the presence of monocytes activate human T-lymphocytes to proliferation. The antigenic nature of stimulatory molecules was supported by the significantly stronger lymphocyte response in persons previously exposed to setae than in non-exposed donors. The nature of such molecules remains to be defined.

STAT5 signaling in expression of the α-subunit of interleukin-2 receptor in human blood lymphocytes

A comparative study of STAT3 and STAT5 activity (assessed by tyrosine phosphorylation level) and the expression of an α-subunit of the interleukin-2 receptor (examined by cytophotometric evaluation of CD25 cell number) during phytohemaglutinin (PHA)-induced proliferation of human blood lymphocytes (HBLs) has been carried out. It was found that the level of STAT3 phosphorylation was high both in resting and competent HBLs and remained unchanged in the presence of PHA or interleukin-2 (IL-2). In contrast to STAT3, phosphorylation of STAT5 was not seen either in resting or competent HBL. In the presence of PHA, STAT5 phosphorylation was observed no earlier than in 2–5 h; maximal phosphorylation was detected after 24 h. In competent HBLs, exogenous IL-2 induced high phosphorylation of STAT5 in 30 min that was retained for the next 24–48 h. Alterations in the level of tyrosine phosphorylation of STAT5 correlated with CD25 expression. WHI-P131, a JAK3 kinase inhibitor, prevents STAT5 activation, CD25 surface expression, and lymphocyte proliferation. It is concluded that JAK3/STAT5 signaling via an IL-2 receptor is necessary to support the long-term expression of a high-affinity αβγc-receptor of IL-2 and HBL optimal proliferation.

Suppression of mitogen-induced lymphocyte proliferation by syringomycin-E

Syringomycin E (SR-E) is low molecular weight bacterial lipodepsipeptide with antifungal properties. Owing to immunosuppressive activities of such compounds as cyclosporine, FK506 and rapamycin, we studied the effect of SR-E on proliferation of human blood lymphocytes in vitro. SR-E, by itself, had no effect but the mitogen-induced lymphocyte proliferation was significantly suppressed. The suppressive effect was more pronounced with pokeweed mitogen (PWM) as compared to phytohemagglutinin (PHA) or monoclonal antibody to CD3 (anti-CD3). Since these mitogens induce cellular immunity (T cell-dependent), SR-E may potentially be a novel immunosuppressive compound.

Suppression of mitogen-induced lymphocyte proliferation by syringomycin-E.

Syringomycin E (SR-E) is a low molecular weight bacterial lipodepsipeptide with antifungal properties. Owing to immunosuppressive activities of such compounds as cyclosporine, FK506 and rapamycin, we studied the effect of SR-E on proliferation of human blood lymphocytes in vitro. SR-E, by itself, had no effect but the mitogen-induced lymphocyte proliferation was significantly suppressed. The suppressive effect was more pronounced with pokeweed mitogen (PWM) as compared to phytohemagglutinin (PHA) or monoclonal antibody to CD3 (anti-CD3). Since these mitogens induce cellular immunity (T cell-dependent), SR-E may potentially be a novel immunosuppressive compound.

Methimazole inhibits peripheral lymphocyte proliferation by inducing S-quiescent phase arrest

The influence of methimazole (MTI) on the mitogenic proliferation of human blood lymphocytes was studied in vitro to evaluate the potential immunomodulatory activity of this antithyroid drug. The effects of the drug on the lymphocyte cell cycle were assessed by multiparametric flow cytometry. Although MTI induced an increase in the number of lymphocytes in the synthesis and G2M compartments, it failed to stimulate proliferation as the cells tended to accumulate in the quiescent S compartment. The effect was dose-dependent over a range from 0.1 to 100mM. These in vitro results indicate that MTI possesses immunosuppressive activity.

Suppression of human blood lymphocyte proliferation upon in vitro preincubation of cells with morphine

Suppression of human blood lymphocyte proliferation upon in vitro preincubation of cells with morphine

Immunoregulatory properties of pulmonary surfactant: effect of lung lining fluid on proliferation of human blood lymphocytes.

Human pulmonary surfactant has not been shown to have immunoregulatory properties. A study was designed to examine the effect of whole surfactant (lyophilised bronchoalveolar lavage fluid) and purified surfactant lipids obtained from normal lungs of three species (man, pig, rabbit) on the lymphoproliferative responses of human peripheral blood lymphocytes to mitogens and alloantigens. Whole surfactant and purified surfactant lipids suppressed the proliferative response to phytohaemagglutinin in a dose dependent manner. The purified lipid fraction appeared to cause more suppression than whole surfactant in all the species. There was significant suppression of the proliferative response to B cell mitogens, T cell mitogens (pokeweed mitogen and phytohaemagglutinin), and alloantigens as tested by allogeneic mixed lymphocyte cultures. These results suggest an immunoregulatory role for pulmonary surfactant, most likely due to the lipid fraction.

The IL-2 Receptor β Chain (p70): Role in Mediating Signals for LAK, NK, and Proliferative Activities

Interleukin-2 (IL-2) induces cytolytic activity and proliferation of human blood lymphocytes. Yet, prior to activation, these cells do not express IL-2 receptors recognized by monoclonal antibodies to the Tac antigen. A novel glycoprotein (IL-2R beta), identified on several lymphocytoid cell lines, has the ability to bind IL-2 alone and to associate with Tac antigen (IL-2R alpha) to form high-affinity IL-2 receptors. It is now reported that IL-2R beta is expressed on both circulating T lymphocytes and large granular lymphocytes in quantities approximately proportional to their responsiveness to IL-2. Studies of the responses of these cells to IL-2 suggest that IL-2R beta mediates the initial phase of induction of lymphokine activated killer (LAK), natural killer (NK), and proliferative activities. Subsequently, IL-2R alpha is induced and functional high-affinity IL-2 receptors are expressed.

Sensitivity to X-irradiation of peripheral blood lymphocytes from ageing donors.

The proliferation of human blood lymphocytes from ageing donors, responding to concanavalin A, showed greater sensitivity to inhibition by X-rays than similar cells from younger donors. This increased sensitivity was associated with deficiency in repair of X-ray-induced damage to nuclear material, as measured by density in sucrose gradients, and with increased incidence of chromosomal damage following exposure of freshly isolated lymphocytes. There was also an increased frequency of spontaneous chromosomal aberrations in ageing subjects whose lymphocytes were deficient in repair of DNA damage.

Permissive effect of substratum contact on DNA synthesis in concanavalin A-treated lymphocytes.

The effects of contact with a solid surface (in the form of adhesive microcarrier beads (Cytodex)) on the induction of proliferation of human blood lymphocytes after exposure to concanavalin A (Con A) were investigated. The duration of the lag phase preceding DNA synthesis was identical in the presence and absence of beads. The kinetic course of initiation of DNA synthesis was exponential but with different rate constants both in the presence and in the absence of beads during the first 4 days of the culture period. Cytodex exerted its effect by increasing the proportion of cells initiating DNA synthesis in response to Con A. To elucidate whether lymphocytes responded to Con A exposure in a dose-dependent manner, cells were seeded at different concentrations and exposed to Con A for different times. At 36 and 48 h after start of stimulation the proportion of cells synthesizing DNA increased with increasing cell number in the cultures. In contrast, the portion of cells synthesizing DNA was markedly decreased at high cell densities 60, 72 and 96 h after start of stimulation. In the presence of microcarrier beads, however, the proportion of cells synthesizing DNA was proportional to the cell number in the cultures also after 60, 72 and 96 h.

In vitro Cytodifferentiation of Human Blood Lymphocytes : 1. Differentiation of Thymus-Derived Lymphocytes

The proliferation of human blood lymphocytes after incubation with either antigen or nonspecific mitogens indicates a process of differentiation. This assumption is supported by several findings: The small lymphocytes profoundly change their cytological structure, as transformed cells following stimulation by PHA, Con. A, tuberculin and MLC had the ultrastructural characteristics of immunoblasts. Blastoid transformed cells with a highly developed vacuolar apparatus were observed in those cultures stimulated by PHA and ALS. This differentiation is paralleled by the development of some functions which characterize T-derived lymphocytes. It was demonstrated that the lymphocytes stimulated by these agents secrete mediators (i.e. a migration inhibition factor) and acquire killer properties. The steps of the cytotoxic process were studied using electron microscopy.