Mitogen-stimulated Lymphocyte Proliferation Research Articles

Prenatal blood metals, per- and polyfluoroalkyl substances and antigen- or mitogen-stimulated cord blood lymphocyte proliferation and cytokine secretion

Prenatal blood metals, per- and polyfluoroalkyl substances and antigen- or mitogen-stimulated cord blood lymphocyte proliferation and cytokine secretion

Prenatal blood metals, per- and polyfluoroalkyl substances and antigen- or mitogen-stimulated cord blood lymphocyte proliferation and cytokine secretion

BackgroundEvidence suggests that prenatal per- and polyfluoroalkyl substances (PFAS) and metals, two classes of chemicals found ubiquitously in human populations, influence immune system development and response. ObjectiveWe evaluated whether first trimester blood PFAS and metals were associated with antigen- or mitogen-stimulated cord blood lymphocyte proliferation and cytokine secretion. MethodsWe measured six PFAS, as well as six nonessential and four essential metals, in first trimester blood from participants in the longitudinal pre-birth Project Viva cohort, recruited between 1999 and 2000 in eastern Massachusetts. We measured antigen- or mitogen-stimulated cord blood mononuclear cell proliferation responses (n = 269–314) and cytokine secretion (n = 217–302). We used covariate-adjusted least absolute shrinkage and selection operator (LASSO) for variable selection and multivariable regression to estimate associations with the immune markers. ResultsEach ng/mL of MeFOSAA was associated with a 3.6% (1.4, 5.8) higher lymphocyte proliferation response after stimulation with egg antigen, as well as 0.8 (0.7, 1.0) reduced odds of having IFN-γ detected in response to dust mite. Each ng/g increment of cesium was associated with 27.8% (−45.1, −4.9) lower IL-10 levels in response to dust mite. Each ng/g increment of mercury was associated with 12.0% (1.3, 23.8) higher IL-13 levels in response to mitogen PHA. Each ng/g increment of selenium and zinc was associated with 0.2% (0.01, 0.4) and 0.01% (0.002, 0.02) higher TNF-α in response to mitogen PHA, respectively. ConclusionsPrenatal metals and PFAS influence cord blood lymphocyte proliferation and cytokine secretion in ways that may increase risk for atopic disease in childhood.

Long-Term Trypsin Treatment Promotes Stem Cell Potency of Canine Adipose-Derived Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) isolated from adipose tissue (adipose-derived stem cells [ADSCs]) are considered one of the most promising cell types for applications in regenerative medicine. However, the regenerative potency of ADSCs may vary because of heterogeneity. Long-term trypsin treatment (LTT) is known to significantly concentrate multilineage-differentiating stress-enduring (Muse) cells from human MSCs. In this study, we aimed to generate cells with high stem cell potency from canine ADSCs using LTT. After 16 h of treatment with trypsin, surviving ADSCs (LTT-tolerant cells) had significantly enhanced expression of stage-specific embryonic antigen (SSEA)-1, a mouse embryonic stem cell marker, and fucosyltransferase 9, one of several fucosyltransferases for SSEA-1 biosynthesis. However, LTT-tolerant cells did not enhance the expression of SSEA-3, a known human Muse cell marker. LTT-tolerant cells, however, showed significantly higher self-renewal capacity in the colony-forming unit fibroblast assay than ADSCs. In addition, the LTT-tolerant cells formed cell clusters similar to embryoid bodies and expressed undifferentiated markers. Moreover, these cells differentiated into cells of all three germ layers and showed significantly higher levels of α 2-6 sialic acid (Sia)-specific lectins, known as differentiation potential markers of human MSCs, than ADSCs. LTT-tolerant cells had a normal karyotype and had low telomerase activity, showing little carcinogenetic potency. LTT-tolerant cells also showed significantly increased activity of transmigration in the presence of chemoattractants and had increased expression of migration-related genes compared with ADSCs. In addition, LTT-tolerant cells had stronger suppressive activity against mitogen-stimulated lymphocyte proliferation than ADSCs. Overall, these results indicated that the LTT-tolerant cells in canine ADSCs have similar properties as human Muse cells (although one of the undifferentiated markers is different) and are expected to be a promising tool for regenerative therapy in dogs.

Hemozoin-induced activation of human monocytes toward M2-like phenotype is partially reversed by antimalarial drugs-chloroquine and artemisinin.

Plasmodium falciparum malaria is the most severe form of malaria with several complications. The malaria pigment‐hemozoin (Hz) is associated with severe anemia, cytokine dysfunction, and immunosuppression, thus making it an interesting target for developing new strategies for antimalarial therapy. Monocytes (MO) in circulation actively ingest Hz released by Plasmodium parasites and secrete pro‐ and anti‐inflammatory cytokines. M1 and M2 types represent the two major forms of MO/macrophages (MQ) with distinct phenotypes and opposing functions. Imbalance in the polarization of these types is reported in many infectious diseases. Though the association of Hz with immunosuppression is well documented, its role in activation of MO in context of M1/M2 phenotypes remains to be addressed. We report here that natural Hz drives human MO toward M2‐like phenotype as evidenced by the expression of M2 signature markers. Hz‐fed MO showed elevated transcript and secreted level of IL‐10, CCL17, CCL1, expression of mannose‐binding lectin receptor (CD206), and arginase activity. Hz attenuated HLA‐DR expression, nitric oxide, and reactive oxygen species production, which are the features of M1 phenotype. Our data also implicate the involvement of p38 MAPK, PI3K/AKT, and NF‐κB signaling pathways in skewing of Hz‐fed MO toward M2‐like type and suppression of mitogen‐stimulated lymphocyte proliferation. Importantly, antimalarial drugs—chloroquine and artemisinin—partially reversed activation of Hz‐induced MO toward M2‐like phenotype. Considering the limitations in the current therapeutic options for malaria, we propose that these drugs may be re‐examined for their potential as immunomodulators and candidates for adjunctive treatment in malaria.

Copper nanoparticles induce early fibrotic changes in the liver via TGF-β/Smad signaling and cause immunosuppressive effects in rats

Copper nanoparticles (Cu NPs) have various uses, including as additives in polymers/plastics, lubricants for metallic coating, and biomedical applications. We investigated the role of transforming growth factor (TGF)-β1 signaling in hepatic damage caused by Cu NPs and explored the effects of a 28-day repeated oral administration to Cu NPs on the immune response. The exposure to Cu NPs caused a dose-dependent increase in Cu levels in the liver and spleen. Cu NPs caused hepatic damage and markedly increased oxidative stress in liver tissues. Cu NPs induced activation of TGF-β1/Smad signaling by induction of vascular endothelial growth factor and matrix metalloproteinase-9. Exposure to Cu NPs also induced activation of Smad-independent pathways, phosphorylation of mitogen-activated protein kinases (MAPKs) and Akt/FoxO3. Consistent with the activation of TGF-β1/Smad-dependent and -independent pathways, Cu NPs markedly increased the deposition and induction of extracellular matrix components, α-smooth muscle actin, and collagens in liver tissues. In addition, repeated exposure to Cu NPs suppressed the proliferation of mitogenically stimulated T- or B-lymphocytes and decreased CD3+ (particularly, CD3+CD4+CD8−) and CD45+ population, followed by decreased levels of immunoglobulins and Th1/Th2 type cytokines. Collectively, Cu NPs caused hepatic damage and induced pro-fibrotic changes, which were closely related to the activation of oxidative stress-mediated TGF-β1/Smad-dependent and -independent pathways (MAPKs and Akt/FoxO3). We confirmed the immunosuppressive effect of Cu NPs via the inhibition of mitogen-stimulated spleen-derived lymphocyte proliferation and suppression of B- or T-lymphocyte-mediated immune responses.

Sea Buckthorn Pomace Supplementation in the Diet of Growing Pigs—Effects on Fatty Acid Metabolism, HPA Activity and Immune Status

There is evidence that sea buckthorn, as a source of n-3 polyunsaturated fatty acids (n-3 PUFA), possesses health-enhancing properties and may modulate neuroendocrine and immune functions. In the present study, we investigated the effect of sea buckthorn pomace (SBP) supplementation in the diet of growing German Landrace pigs on fatty acids in the blood and hypothalamus, peripheral immune parameters and mRNA expression of corticotropin-releasing hormone (CRH), mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) in the hypothalamus and spleen. Pigs were fed diets supplemented with 12% of dried SBP or 0% SBP (control group) over an intervention period of eight weeks. The fatty acid profiles in blood plasma were significantly affected by SBP supplementation only for C18:2n-6 and n-6/n-3 PUFA ratio compared with the control group. SBP supplementation did not significantly affect the fatty acid concentrations in the hypothalamus. Furthermore, there were no significant differences in mRNA expression of CRH, MR and GR in the hypothalamus or of GR mRNA expression in the spleen. Concerning the immune status, the plasma IgG levels tended to be higher in SBP pigs, whereas the leukocyte distribution, mitogen-stimulated lymphocyte proliferation, and serum IgM levels remained unchanged. In conclusion, the SBP supplementation of the diet only caused moderate effects on fatty acid metabolism, but no significant effects on hypothalamic–pituitary–adrenal (HPA) activity and immunity in growing pigs. It seems that a beneficial effect of dietary n-3 PUFA on health and welfare is more likely to be expected during stressful situations.

Immunomodulatory effects of umbilical cord-derived mesenchymal stem cells.

Umbilical cord blood (UCB) is of great interest as a source of stem cells for use in cellular therapies. The immunomodulatory effect of mesenchymal stem cells (MSCs) originating from bone marrow, adipose tissue and amniotic membrane has previously been reported. In this study, MSCs were isolated from UCB with the aim of evaluating their immunomodulatory effects on proliferation of PB lymphocytes by two different techniques; namely, 5-bromo-2-deoxyuridine ELISA and a carboxy fluorescein diacetate succinimidyl ester flow cytometric technique. MSCs were isolated from UCB, propagated until Passage four, and then characterized for cell surface markers by flow cytometry and ability to differentiate towards osteocytes and adipocytes. Immunosuppressive effects on PB lymphocytes were examined by co-culturing mitomycin C-treated UCB MSCs with mitogen-stimulated lymphocytes for 72 hr. Thereafter, proliferation of lymphocytes was detected by CFSE flow cytometry and colorimetric ELISA. The titers of cytokines in cell culture supernatant were also assayed to clarify possible mechanisms of immunomodulation. UCB MSCs suppressed mitogen-stimulated lymphocyte proliferation, which occurs via both cell-cell contact and cytokine secretion. Titers of transforming growth factor beta and IL 10 increased, whereas that of IFN-γ decreased in the supernatants of co-cultures. Thus, UCB MSCs suppress the proliferation of mitogen-stimulated lymphocytes. However further in vivo studies are required to fully evaluate the immunomodulatory effects of UCB MSCs.

Immunotoxic effects of an industrial waste incineration site on groundwater in rainbow trout (Oncorhynchus mykiss)

The discharge of organic waste from the petrochemical industry into the Mercier lagoons caused major groundwater contamination. The objective of this study was to determine the immunotoxic potential of three groundwater wells at increasing distance from the incinerator dumping site (1.17, 2.74 and 5.40 km). Rainbow Trout were exposed to increasing concentrations of water from three groundwater wells for 14 days. Immunocompetence was characterized by phagocytosis, mitogen-stimulated proliferation of lymphocytes, cell cycle analysis and apoptosis. A significant increase in innate (phagocytosis) and specific immune response (B lymphocyte proliferation) was observed in trout exposed to water collected from the well at 2.74 km. However, phagocytosis activity was suppressed in groups at 1.17 and 5.40 km. The proportion of lymphocytes in S phase was significantly increased in groups at 2.74 and 5.40 km, while lymphocytes in G0/G1 phase were decreased in all three exposure groups. Additionally, dexamethasone (DEX)-induced apoptosis of lymphocytes was significantly reduced in the group at 2.74 km, which suggests decreased lymphocyte turnover. Furthermore, the ratio of DEX-induced apoptosis/apoptosis was lower in the groups at 2.74 and 5.40 km. In summary, our experiments have shown that exposure to the mixture of organic compounds present in Mercier groundwater modulates phagocytosis and cell proliferation, disrupts the cell cycle and reduces the ratio of DEX-induced apoptosis/apoptosis. It is concluded that groundwater collected in the vicinity of an incinerator containment field could impact immunocompetence in fish.

Vascular endothelial growth factor-A enhances indoleamine 2,3-dioxygenase expression by dendritic cells and subsequently impacts lymphocyte proliferation

Dendritic cells (DCs) are antigen (Ag)-presenting cells that activate and stimulate effective immune responses by T cells, but can also act as negative regulators of these responses and thus play important roles in immune regulation. Pro-angiogenic vascular endothelial growth factor (VEGF) has been shown to cause defective DC differentiation and maturation. Previous studies have demonstrated that the addition of VEGF to DC cultures renders these cells weak stimulators of Ag-specific T cells due to the inhibitory effects mediated by VEGF receptor 1 (VEGFR1) and/or VEGFR2 signalling. As the enzyme indoleamine 2,3-dioxygenase (IDO) is recognised as an important negative regulator of immune responses, this study aimed to investigate whether VEGF affects the expression of IDO by DCs and whether VEGF-matured DCs acquire a suppressor phenotype. Our results are the first to demonstrate that VEGF increases the expression and activity of IDO in DCs, which has a suppressive effect on Ag-specific and mitogen-stimulated lymphocyte proliferation. These mechanisms have broad implications for the study of immunological responses and tolerance under conditions as diverse as cancer, graft rejection and autoimmunity.

IMMUNOMODULATORY ACTIVITY OF THE WATER EXTRACT OF Thymus vulgaris, Thymus daenensis, AND Zataria multiflora ON DENDRITIC CELLS AND T CELLS RESPONSES

Thymus vulgaris (thyme), Thymus daenensis, and Zataria multiflora are medicinal plants being used widely for infections and inflammatory diseases in folk medicine. In this study, the effects of the water extract of these plants on the activation of dendritic cells (DCs) and T cells was investigated. Both T. vulgaris and Z. multiflora decreased the proliferation of mitogen-stimulated lymphocytes, whereas T. daenensis induced cell proliferation in a dose-dependent manner (p < 0.001). All the three plants increased the CD40 expression on DCs (p < 0.04). The extent of allogenic T cell proliferation in the presence of T. vulgaris and Z. multiflora extracts was significantly decreased (p < 0.02). The effect of the extracts on secretion of IFN-γ and IL-4 cytokines showed that none of the extracts influenced the pattern of cytokine production by T helper (Th) cells toward a Thl or Th2 profile. In conclusion, all the extracts had the ability to activate DCs. Whereas Z. multiflora and T. vulgaris extracts showed immunoihibitory effects on allogenic T cell proliferation, the main effect of T. daenensis was on mitogenic T cell response. These data may partly explain the mechanisms underlying the beneficial immunomodulatory effects of these extracts in infections and immune-related diseases.

Higher Sensitivity of Peripheral Blood Lymphocytes to Endogenous Glucocorticoid in Renal Transplant Recipients Treated With Tacrolimus, as Compared to Those Treated With Cyclosporine.

Lymphocyte sensitivity to endogenous glucocorticoid cortisol could be a biological marker for safe reduction and withdrawal of steroids in renal transplant recipients. We compared peripheral lymphocyte sensitivity with cortisol between transplant recipients treated with tacrolimus (Tac) and those treated with cyclosporine. The suppressive efficacies of cortisol against T-cell mitogen-stimulated proliferation of peripheral lymphocytes were investigated in 44 renal transplant patients, who either had reduced or been withdrawn from steroid treatment. Twenty of the 44 patients were treated with Tac, and the other 24 patients were treated with cyclosporine A (CyA). The lymphocyte sensitivity to cortisol was compared between these two patient groups. The cortisol IC50 values in the Tac and CyA groups were 0.09 ± 0.12 and 14.2 ± 12.7 ng/ml, respectively. Lymphocyte sensitivity to cortisol in the Tac-treated group was significantly higher than that in the CyA-treated group (p = 0.0283). On the other hand, incidences of steroid withdrawal syndrome and increases in serum creatinine concentration were not significantly different between the Tac and CyA groups. Lymphocyte sensitivity to cortisol was higher in the Tac-treated patients than that in the CyA-treated ones. Since the cortisol sensitivity of peripheral lymphocytes is suggested to be a predictive marker for safe steroid withdrawal, Tac administration shows promise in aiding successful withdrawal of steroid treatment in long-term renal transplant recipients.

Adipogenic differentiation alters the immunoregulatory property of mesenchymal stem cells through BAFF secretion

Although it has been widely demonstrated that mesenchymal stem cells (MSCs) exert potent immunosuppressive effect, there is little information as to whether adipogenic-differentiated MSCs (adi-MSCs) share the same property. Here, adi-MSCs enhanced alloantigen or mitogen-stimulated lymphocyte proliferation, whereas undifferentiated MSCs (ud-MSCs) inhibited the proliferation. Transwell experiment showed that the stimulatory effect of adi-MSCs was cell–cell contact-independent, and required soluble factors. Furthermore, the supernatant of cultured adi-MSCs could effectively costimulate T and B-lymphocyte proliferation and activation in the presence of anti-CD3 and anti-mu chain treatment, respectively. Production of cytokines interferon-gamma and tumor necrosis factor-alpha by T cells, and Ig secretion by B cells also were increased by the supernatant of cultured adi-MSCs. Mechanism conducted showed that the mRNA and protein expression of costimulatory molecule B-cell activating factor (BAFF) was upregulated, and soluble BAFF was secreted in MSCs after adipogenic differentiation. By blocking the BAFF molecule with specific monoclonal antibody in the culture, T and B-lymphocyte proliferation and activation was stimulated by adi-MSCs or the supernatants were greatly reduced. In conclusion, adipogenic differentiation may alter the immunoregulatory property of MSCs, leading to stimulation of lymphocytes response. The BAFF molecule secreted by the adi-MSCs was responsible for this event.

In vitro Effects of L-Ascorbic Acid and Acrylamide on Lymphocyte Proliferation in Young and Aged Mice

This study examined the effects of Acrylamide (ACR) and L-ascorbic acid (AsA) on the proliferation of splenocytes and the mitogen-stimulated lymphocyte proliferation in young (8 weeks) and aged (82 weeks) C57BL/6 male mice in vitro. AsA increased splenocyte proliferation in both groups; however, this effect was higher in old mice, while the proliferation of lymphocyte was decreased except for treatment at 1 ㎍/㎖ low concentration in both mice. In addition, ACR treatment resulted in decreased LPS-induced B lymphocyte proliferation and ConA-induced T lymphocyte proliferation in both groups. However, AsA increased LPS/ConA-induced lymphocyte proliferation in young groups and had no effects in old mice except at 0.5 ㎍/㎖. Thus, the present data indicate that there is no difference effect of ACR and AsA on lymphocyte proliferation, whereas the effect of AsA on mitogen-induced cell proliferation was reduced in old mice. Overall, our results suggest that various immunomodulators have differing effects of lymphocytic proliferation on young versus aged mice.

Alteration of lymphocyte opioid receptors in methadone maintenance subjects

Methadone maintenance therapy is the most widely used treatment in patients with heroin addiction. Multiple studies have suggested that both current and former heroin addicts entering a methadone maintenance treatment program have altered immune function. Our previous study indicated that heroin addicts have depressed mitogen-stimulated lymphocyte proliferation and a decrease in the modulation of lymphocyte surface markers. This immunosuppression may be mediated via the direct interaction of opiates with lymphocyte opioid receptors. In order to test this hypothesis, the levels of opioid receptors on immune cells obtained from heroin users were determined using saturation binding, and it was found that former heroin addicts on methadone maintenance treatment had a significantly reduced maximum number ( B max) of [ 3H]naloxone binding. The B max values were 51.3 ± 7.6 fmol/mg protein for the non-addicted group and 25.3 ± 3.1 fmol/mg protein for the methadone maintenance group. Opioid receptor gene expression on the immune cell was determined using a semi-quantitative reverse-transcription polymerase chain reaction technique with specific pairs of primers to amplify mu- and delta-opioid receptor mRNAs. Both types of mRNAs were significantly decreased in lymphocytes obtained from the former heroin addicts on methadone maintenance subjects. Similarly, in an in vitro study, 100 μM methadone significantly down-regulated both mu- and delta-opioid receptor mRNA expressions in cultured lymphocytes obtained from naïve subjects. This effect was prevented by including 100 μM naloxone or pretreating with 50 ng/ml pertussis toxin. The data presented indicate that chronic opiate exposure was associated with down-regulation of G-protein-coupled opioid receptor gene expression in human lymphocytes.

An in vitro study of liposomal curcumin: Stability, toxicity and biological activity in human lymphocytes and Epstein-Barr virus-transformed human B-cells

Curcumin is a multi-functional and pharmacologically safe natural agent. Used as a food additive for centuries, it also has anti-inflammatory, anti-virus and anti-tumor properties. We previously found that it is a potent inhibitor of cyclosporin A (CsA)-resistant T-cell co-stimulation pathway. It inhibits mitogen-stimulated lymphocyte proliferation, NFκB activation and IL-2 signaling. In spite of its safety and efficacy, the in vivo bioavailability of curcumin is poor, and this may be a major obstacle to its utility as a therapeutic agent. Liposomes are known to be excellent carriers for drug delivery. In this in vitro study, we report the effects of different liposome formulations on curcumin stability in phosphate buffered saline (PBS), human blood, plasma and culture medium RPMI-1640 + 10% FBS (pH 7.4, 37 °C). Liposomal curcumin had higher stability than free curcumin in PBS. Liposomal and free curcumin had similar stability in human blood, plasma and RPMI-1640 + 10% FBS. We looked at the toxicity of non-drug-containing liposomes on 3H-thymidine incorporation by concanavalin A (Con A)-stimulated human lymphocytes, splenocytes and Epstein-Barr virus (EBV)-transformed human B-cell lymphoblastoid cell line (LCL). We found that dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylglycerol (DMPG) were toxic to the tested cells. However, addition of cholesterol to the lipids at DMPC:DMPG:cholesterol = 7:1:8 (molar ratio) almost completely eliminated the lipid toxicity to these cells. Liposomal curcumin had similar or even stronger inhibitory effects on Con A-stimulated human lymphocyte, splenocyte and LCL proliferation. We conclude that liposomal curcumin may be useful for intravenous administration to improve the bioavailability and efficacy, facilitating in vivo studies that could ultimately lead to clinical application of curcumin.

Blood metal levels and metal-influenced immune functions of harbour seals in captivity

Immunological blood parameters and the effects of environmental pollutants on the immune system are important to assess the health status of seals. Animals living permanently in seal centres are useful for development and validation of diagnostic tools for free-ranging animals. In this study, parameters of cellular immunity as well as metal concentrations in blood and metal influence on cell proliferation of seven seals from a seal centre were investigated repeatedly using multi-element analysis and a lymphocyte proliferation assay. The metal concentrations, except for tin and chromium, were in general comparable to those of free-ranging animals of the North Sea. The unstimulated and mitogen-stimulated lymphocyte proliferation showed strong intra- and inter-individual variability, which reflected variability in activation of the immune status. Furthermore, both immunosuppressive and stimulative influences of metals on lymphocytes were found. Summarising, the methods used in this investigation provided useful information on these animals, and their application to free-ranging animals can be recommended.

Effects of flaxseed lignan on mitogen stimulated lymphocyte proliferation

Effects of flaxseed lignan on mitogen stimulated lymphocyte proliferation

Controlled study of enteral arginine supplementation in burned children: impact on immunologic and metabolic status

Objective We compared the effects of an arginine-supplemented diet with those of an isocaloric isonitrogenous diet on immune and metabolic response of children with burns. Methods This was a double-blind, randomized, placebo-controlled trial in a burn treatment center of a pediatric hospital in Santiago, Chile. All children (1–5 y of age) admitted within 48 h of a moderate to deep burn injury covering 10% to 40% of total body surface area were evaluated. Twenty-eight children met the criteria and were randomly assigned to receive an arginine-supplemented diet (AG; n = 14) or an isocaloric isonitrogenous diet (CG; control, n = 14) for 14 d. Samples were collected at admission (baseline) and on days 7 and 14 for lymphoproliferative response to mitogens, plasma interleukins (interleukin-1, interleukin-6, tumor necrosis factor-α), plasma arginine and ornithine levels, serum C-reactive protein, prealbumin, albumin, glucose, and total urinary nitrogen. Results The AG enhanced lymphoproliferative responses (analysis of variance, P < 0.05), which were 72% of normal at baseline in both groups; by day 7 responses increased to 144% in the AG group and decreased to 56% in the CG group; both groups returned to normal by day 14. Baseline interleukin-6 was significantly increased in all children. There were no differences in plasma concentrations of interleukin-1, interleukin-6, tumor necrosis factor-α, C-reactive protein, prealbumin, albumin, or glucose between the AG and CG groups. On day 7 plasma ornithine levels increased significantly in the AG versus CG group ( P < 0.05); arginine levels showed no change. Conclusions An exclusively AG improves mitogen-stimulated lymphocyte proliferation in burned children. The benefits of arginine for the immune system do not appear to be related to a metabolic response. The biological significance of this finding remains to be determined.

Associations of cord blood fatty acids with lymphocyte proliferation, IL-13, and IFN-γ

N-3 and n-6 polyunsaturated fatty acids (PUFAs) have been hypothesized to have opposing influences on neonatal immune responses that might influence the risk of allergy or asthma. However, both n-3 eicosapentaenoic acid (EPA) and n-6 arachidonic acid (AA) are required for normal fetal development. We evaluated whether cord blood fatty acid levels were related to neonatal immune responses and whether n-3 and n-6 PUFA responses differed. We examined the relation of cord blood plasma n-3 and n-6 PUFAs (n = 192) to antigen- and mitogen-stimulated cord blood lymphocyte proliferation (n = 191) and cytokine (IL-13 and IFN-gamma; n = 167) secretion in a US birth cohort. Higher levels of n-6 linoleic acid were correlated with higher IL-13 levels in response to Bla g 2 (cockroach, P = .009) and Der f 1 (dust mite, P = .02). Higher n-3 EPA and n-6 AA levels were each correlated with reduced lymphocyte proliferation and IFN-gamma levels in response to Bla g 2 and Der f 1 stimulation. Controlling for potential confounders, EPA and AA had similar independent effects on reduced allergen-stimulated IFN-gamma levels. If neonates had either EPA or AA levels in the highest quartile, their Der f 1 IFN-gamma levels were 90% lower (P = .0001) than those with both EPA and AA levels in the lowest 3 quartiles. Reduced AA/EPA ratio was associated with reduced allergen-stimulated IFN-gamma level. Increased levels of fetal n-3 EPA and n-6 AA might have similar effects on attenuation of cord blood lymphocyte proliferation and IFN-gamma secretion. The implications of these findings for allergy or asthma development are not yet known.

A Phase I Multiple‐Dose Escalation Study Characterizing Pharmacokinetics and Safety of ABT‐578 in Healthy Subjects

ABT-578, a sirolimus analog, is being developed for administration from drug-eluting stents to prevent postimplantation neointimal hyperplasia. The purpose of this study was to evaluate the safety, tolerability, and pharmacokinetics of multiple doses of ABT-578. Healthy subjects randomly received placebo or ABT-578 (200, 400, or 800 microg) as daily intravenous infusions for 14 days. ABT-578 blood pharmacokinetics and urine excretion on days 1 and 14 were determined. The effect of ABT-578 on mitogen-stimulated lymphocyte proliferation was assessed. ABT-578 pharmacokinetics was described by a 3-compartment open model. The mean CL, V(ss), and t(1/2) ranges were 4.0 to 4.6 L/h, 92.5 to 118.0 L, and 24.7 to 31.0 hours, respectively. ABT-578 pharmacokinetics was dose and time invariant. Approximately 0.1% of ABT-578 was excreted in the urine. ABT-578 was well tolerated, and no systemic changes were observed in the mitogen-stimulated lymphocyte proliferation. ABT-578 was shown to be safe over a wide range of systemic exposures.