Influence of iodide excess and interferon-gamma on human primary thyroid cell proliferation, thyroglobulin secretion, and intracellular adhesion molecule-1 and human leukocyte antigen-DR expression.

BACKGROUND: The effect of iodide on thyroid cell proliferation and function in vivo or in cultured thyroid cells has been previously reported and is still controversial. The aim of this study was to clarify these conflicting results by examining if prolonged high iodide exposition with or without interferon (IFN)-gamma has an effect on human primary thyroid cell proliferation, thyroglobulin (Tg) production, and intercellular adhesion molecule-1 (ICAM-1) and human leukocyte antigen (HLA)-DR expression. METHODS: Primary human thyroid cells were used. Cells were cultured in Coon's modified Ham's F-12 medium supplemented with 5% fetal calf serum in monolayer conditions to induce proliferation and were aggregated for molecular expression and Tg production analysis. HLA-DR and ICAM-1 expression were measured by flow cytometry and Tg by immunometric assay. RESULTS: Potassium iodide (KI) was more potent in arresting primary human thyroid cell proliferation as compared to sodium iodide and the effect was mediated by its action at G0/G1 and G2/M phases of the cell cycle. There were no signs of apoptosis or necrosis. An excess of KI alone did not change the expression of HLA-DR and Tg production, but gradually increased ICAM-1. Low-dose IFN-gamma and excess KI in combination transiently inhibited HLA-DR expression, while ICAM-1 was expressed at a higher level than with IFN-gamma alone. Tg production was moderately increased with low-dose IFN-gamma. However, a combination of high-dose KI with low-dose IFN-gamma significantly decreased Tg secretion, compared with IFN-gamma alone. CONCLUSIONS: Augmented ICAM-1 in the presence of iodide excess and low-dose IFN-gamma could induce secretion of proinflammatory cytokines and lymphocytic infiltration in the thyroid gland. Decreased Tg production in the presence of KI excess and IFN-gamma could explain the development of hypothyroidism after adding iodide in a diet of subjects that already have lymphocytic infiltration and/or mild inflammation in the thyroid gland.

Glutamine-enriched enteral nutrition increases HLA-DR expression on monocytes of trauma patients.

The aim of this study was to investigate the effect of glutamine-(Gln)-enriched enteral nutrition (EN) on human leukocyte antigen (HLA)-DR and FcgammaR1/CD64 expression on monocytes and plasma glutamine concentrations in multi-trauma patients. HLA-DR expression on monocytes is crucial in the presentation of foreign antigen to the immune system and is severely reduced in trauma patients. In vitro monocyte HLA-DR and FcgammaRI/CD64 expression is dependent on glutamine availability. To study the effect of glutamine supplemented enteral nutrition on HLA-DR and FcgammaRI/CD64 expression on CD14(+) monocytes, 55 multi-trauma patients were studied in a randomized, double-blinded, controlled trial. Trauma patients received either a Gln-enriched EN (glutamine group, n = 28) or an isocaloric, isonitrogenous control EN (control group, n = 27) and were compared with a group of age-matched healthy volunteers (healthy volunteers, n = 53). On d 1, 5, 9 and 14 after trauma, expressions of HLA-DR and FcgammaRI/CD64 were determined on CD14(+) monocytes using FACS analysis. Plasma glutamine levels were measured using HPLC. Plasma glutamine was lower in both trauma patient groups compared with healthy volunteers and from d 3 to d 5; glutamine was higher in the glutamine group than in the control group. On d 1, HLA-DR expression was much lower in both trauma patient groups than in healthy volunteers. HLA-DR expression was greater on d 5, 9 and 14 in the glutamine group than in the control group. FcgammaRI/CD64 expression on monocytes of trauma patients was not different than the expression of healthy volunteers. This study showed that glutamine-enriched enteral nutrition was associated with a higher HLA-DR expression on CD14(+) monocytes of trauma patients. No difference in monocyte FcgammaRI/CD64 expression was detected between patients that received the two enteral diets and between trauma patients and the healthy volunteers. Increased HLA-DR expression may improve cellular immune function and may be involved in the beneficial effect of glutamine on the occurrence of infections in trauma patients.

The proinflammatory CD14+CD16+DR++ monocytes are a major source of TNF.

In human blood two monocyte populations can be distinguished, i.e., the CD14(++)CD16(-)DR(+) classical monocytes and the CD14(+)CD16(+)DR(++) proinflammatory monocytes that account for only 10% of all monocytes. We have studied TNF production in these two types of cells using three-color immunofluorescence and flow cytometry on whole peripheral blood samples stimulated with either LPS or with the bacterial lipopeptide S-(2,3-bis(palmitoyloxy)-(2-RS)-propyl)-N-palmitoyl-(R)-Cys-(S)-Ser-(S)-Lys(4)-OH,trihydrochloride (Pam3Cys). After stimulation with LPS the median fluorescence intensity for TNF protein was 3-fold higher in the proinflammatory monocytes when compared with the classical monocytes. After stimulation with Pam3Cys they almost exclusively responded showing 10-fold-higher levels of median fluorescence intensity for TNF protein. The median fluorescence intensity for Toll-like receptor 2 cell surface protein was found 2-fold higher on CD14(+)CD16(+)DR(++) monocytes, which may explain, in part, the higher Pam3Cys-induced TNF production by these cells. When analyzing secretion of TNF protein into the supernatant in PBMCs after depletion of CD16(+) monocytes we found a reduction of LPS-induced TNF by 28% but Pam3Cys-induced TNF was reduced by 64%. This indicates that the minor population of CD14(+)CD16(+) monocytes are major producers of TNF in human blood.

Stimulation of the maturation of dendritic cells in vitro by a fermented mistletoe extract.

BACKGROUND: Dendritic cells (DC) play a key role during the initiation of specific immune responses. In cancer patients, however, an alteration of their function was observed. In our investigation we analysed the influence of a fermented mistletoe extract often used for adjuvant treatment of cancer patients on the generation and maturation of DC. MATERIALS AND METHODS: Monocytes from healthy individuals were incubated with a fermented mistletoe extract in the presence or absence of GM-CSF/IL-4. Surface marker expression was measured by flow cytometry. RESULTS: While there was no relevant effect on the generation of DC in the absence or presence of GM-CSF/IL-4 in 5-day cultures, the mistletoe extract significantly stimulated the maturation of pre-generated immature DC, as evidenced by a heightened expression of CD83. Like the positive control TNF-alpha, the mistletoe extract significantly activated CD80 and CD86 as well as HLA class I and II molecules on these cells. CONCLUSION: Our data clearly demonstrate an influence of the mistletoe extract on the maturation of DC, but it remains to be elucidated whether the function of DC is also activated and, especially, whether this effect can be observed in tumour patients as well.

Histone deacetylase activity represses gamma interferon-inducible HLA-DR gene expression following the establishment of a DNase I-hypersensitive chromatin conformation.

Expression of the retinoblastoma tumor suppressor protein (Rb) is required for gamma interferon (IFN-gamma)-inducible major histocompatibility complex class II gene expression and transcriptionally productive HLA-DRA promoter occupancy in several human tumor cell lines. Treatment of these Rb-defective tumor cell lines with histone deacetylase (HDAC) inhibitors rescued IFN-gamma-inducible HLA-DRA and -DRB mRNA and cell surface protein expression, demonstrating repression of these genes by endogenous cellular HDAC activity. Additionally, Rb-defective, transcriptionally incompetent tumor cells retained the HLA-DRA promoter DNase I-hypersensitive site. Thus, HDAC-mediated repression of the HLA-DRA promoter occurs following the establishment of an apparent nucleosome-free promoter region and before transcriptionally productive occupancy of the promoter by the required transactivators. Repression of HLA-DRA promoter activation by HDAC activity likely involves a YY1 binding element located in the first exon of the HLA-DRA gene. Chromatin immunoprecipitation experiments localized YY1 to the HLA-DRA gene in Rb-defective tumor cells. Additionally, mutation of the YY1 binding site prevented repression of the promoter by HDAC1 and partially prevented activation of the promoter by trichostatin A. Mutation of the octamer element also significantly reduced the ability of HDAC1 to confer repression of inducible HLA-DRA promoter activation. Treatment of Rb-defective tumor cells with HDAC inhibitors greatly reduced the DNA binding activity of Oct-1, a repressor of inducible HLA-DRA promoter activation. These findings represent the first evidence that HDAC activity can repress IFN-gamma-inducible HLA class II gene expression and also demonstrate that HDAC activity can contribute to promoter repression following the establishment of a DNase I-hypersensitive chromatin conformation.

NFkappaB activation, TNF-alpha expression, and apoptosis in the AIDS-Dementia-Complex.

The role of NFkappaB activation and its relationship to inflammatory mediators and apoptosis in the HIV-infected brain have remained uncertain. The cellular and regional distribution of NFkappaB, TNF-alpha, and apoptosis was examined in the frontal cortex (FC), deep white matter (DWM) and the basal ganglia (BG) of 17 patients with ADC. Nuclear staining for NFkappaB was localized predominantly to perivascular microglia/macrophages in the BG and DWM and correlated with ADC severity. Correlations were further found with HLA-DR, iNOS, TNF-alpha, and gp41 expression in these regions. The number of TUNEL-positive cells, particularly in the BG, correlated with ADC stage. Logistic regression analysis further showed a significant relationship between the likelihood of TUNEL staining in the BG and worsening cognitive impairment.

Hyperthermia inhibits proliferation and stimulates the expression of differentiation markers in cultured thyroid carcinoma cells.

In the last two decades hyperthermia has increasingly been used as adjuvant therapy for the treatment of malignant tumours. The effects of heat were therefore analysed on cultured thyroid epithelial cells from patients with thyroid cancer and from non-malignant control thyroids. Purified thyroid cells were subjected to heat treatment (42.5 degrees C; 90 min). After 24 h [3H]thymidine incorporation was assessed and the expression of heat shock protein 72 (hsp72), thyroglobulin, CD54 (ICAM-I) and MHC class-Il were analysed by immunofluorescence staining. Additionally mRNA analysis was performed by Northern blotting. Whereas hyperthermia inhibited the proliferation of thyroid cells, it significantly increased the expression of hsp72, thyroglobulin, CD54 and HLA-DR (P < 0.05). Our results suggest that hyperthermia may suppress growth while supporting differentiation and immune recognition in thyroid cancer. It may therefore be beneficial as a treatment for patients with thyroid carcinoma.

Influence of beta-carotene on immune functions.

Recent reports have demonstrated that beta-carotene, a nontoxic carotenoid, is able to stimulate immune functions in humans. The purpose of this study is to understand the mechanisms of immunoenhancement by carotenoids in order to explain their anticancer effects. We have evaluated the clinical efficacy of beta-carotene, given 30 mg/day orally, for treatment of oral leukoplakia patients. Patients who responded to beta-carotene treatment showed increased plasma levels of TNF-alpha. Epithelial cells from these patients were characterized in vitro. These results may lead to a better understanding of the therapeutic use of beta-carotene in humans.

Modulation of interferon-gamma-induced HLA-DR expression on the human keratinocyte cell line SCC-13 by ultraviolet radiation.

Cell surface expression of major histocompatibility determinants on epidermal keratinocytes is a characteristic feature of a number of inflammatory dermatoses and in all likelihood is caused by diffusion of human leukocyte antigen (HLA)-DR-inducing cytokines from cells present in the dermal mononuclear cell infiltrate. Many of these same disorders respond to ultraviolet (UV) radiation phototherapy. Using the human SCC-13 keratinocyte cell line as a model, UV radiation was found to inhibit interferon-gamma-induced HLA-DR expression. Inhibition correlated closely with decreased steady-state levels of HLA-DR mRNA. These findings provide evidence that the therapeutic effect of UV radiation phototherapy may be mediated by its capacity to down-regulate cytokine-induced keratinocyte HLA-DR expression.

A new tripeptide, Pol 509, influences biochemical events associated with antigen presentation efficiency of PPD-specific EBV-B cells.

A synthetic tripeptide (pGLU-LEU-TRP-OCH3) Pol 509, derived from snake venom, was studied directly by analyzing the interactions with synthetic lipid bilayers using NMR spectroscopy. Functional studies were also performed by measuring the effects: i), on early biochemical events (adenyl cyclase and phospholipase C activation products), intermediate (surface Ag expression) and late (DNA synthesis) parameters following B-cell activation elicited by PPD-linkage to specific membrane Ig; and ii), on the presentation of PPD to Ag-specific T-cell lines. Comparative experiments using PMA and IFN-gamma were also performed. We found that all parameters studied were affected by Pol 509 treatment. In fact, while PPD linkage to mlg reversed the balance between cAMP and IP3 existing in unstimulated EBV-B cells, Pol 509 reduced the PPD-induced accumulation of cAMP to control values and induced a further decrease of IP3 level. Pol 509-mediated decrease of these second messenger levels was accompanied by a slight increase of HLA-DR molecule expression and DNA synthesis inhibition. Furthermore, Pol 509 enhanced the efficiency of PPD presentation to T-cell lines. Taken together, these observations suggest that Pol 509, which enhances Ag presentation by modifying second messenger levels, may be considered as a new immunomodulatory drug with immunopotentiating activity.

Anti-CD4 monoclonal antibody therapy in severe psoriasis.

We report here the treatment of psoriasis, a chronic inflammatory skin disease characterized by uncontrolled keratinocyte proliferation, with BB14, a CD4 murine IgG1 antibody. Three patients with severe psoriasis were treated with anti-CD4 mAb infusions (0.2 mg/kg/day for the first patient, 0.4 mg/kg/day for 2 days and 0.8 mg/kg/day during the following days for the 2 others) for 7 or 8 days, without other therapy. Rapid clinical improvement, with major reduction of the Psoriasis Area Severity Index, was observed during 1 month after treatment. Moderate decreases in CD4+ blood cells occurred in the last two patients but not in the first one. Circulating T cells coated with anti-CD4 mAb were detectable during the first 48 h in the first patient and from day 1/2 to day 7/8 in the two others. The density of CD4 molecules on the surfaces of peripheral blood lymphocytes was decreased in all patients and remained low as long as anti-CD4 mAb was detectable in patient serum. The maximal 24 h residual mAb levels ranged from 0.3 microgram/ml in the first patient to 3.8 and 7.0 microgram/ml in the two others. The three patients produced IgM antibodies against the anti-CD4 mAb at day 7/8 or 15 and two patients had IgG antibodies at day 15. Lesional skin samples demonstrated (1) gradual improvement in parakeratosis, papillomatosis and acanthosis, (2) decreased expression of ICAM-1 and HLA-DR by keratinocytes, (3) an increase in CD1a+ Langerhans cell number, (4) partial decrease in epidermal T cell infiltrate and (5) no major change in the dermal infiltrate composed of CD3+, TcR alpha beta+, CD45Ro+, HLA-DR+ T cells. We conclude that anti-CD4 mAb administration can induce a rapid and major improvement in psoriatic lesions, with immunohistochemical changes different from those induced by cyclosporin A or 8-methoxypsoralen plus long wave UV light (PUVA) therapy. Our data provide strong evidence for a critical role of CD4+ lymphocytes in psoriasis.

Kinetics of MHC class II and transferrin receptor expression by colostral cells stimulated in vitro with concanavalin A and myelin basic protein.

The colostral cells, regarded generally as being protective, have been shown to differ in a number of membrane properties (rosetting, adherence, mobility) from the corresponding peripheral blood mononuclear cells. After in vitro stimulation with Con A or MBP 50% to 70% of the human colostral cells appeared HLA-DR positive at the first 24 h of culturing. The CD71 expression reached a maximum on culture days 2-3 coinciding with the maximal proliferative response. With regard to the phenotypic characteristics and their kinetics, the human colostral cells did not show significant differences from the peripheral blood mononuclear cells.

Human monoblastoid cell line U-937 cultured in protein-free medium: immunophenotype, cytochemical and biochemical markers.

Human monoblastoid cell line U-937 was adapted to grow in protein-free (protein-free hybridoma--PFH) medium and cloned by limiting dilution. Resulting cell subline (U-937/PF) cultured in protein-free medium was characterized by immunological, cytochemical and biochemical techniques. There were no major differences in immunophenotype (determined by FACS analysis with monoclonal antibodies directed to HLA and CD antigens) and cytochemical markers between the U-937/PF cells cultured in protein-free cell culture medium and parental U-937 cell cultured in serum-supplemented medium. Maximal cell density was slightly decreased in protein-free culture as compared to the parental cell line in FCS-supplemented medium. Cell viability and cell DNA histograms (determined by propidium iodide cytofluorimetry) showed no major differences between parental U-937 and U-937/PF cells. Phorbol ester (TPA)-induction of differentiation-associated cell markers resulted in a proliferation arrest and accumulation of G0/G1 cells in both sublines. All-trans retinoic acid and, to a lesser extent, TPA-stimulated NBT reduction was higher in parental U-937 cells cultured in serum-supplemented medium as compared to U-937/PF cells. Quantitative differences in the expression and inducibility of some cytochemical markers (beta-glucuronidase, chloroacetate esterase) were found between both examined sublines. Described U-937/PF subline cultured in a protein-free cell culture medium (PFH) appeared as a potential tool for studies of in vitro inducing agents and serum components with differentiation promoting (or inhibiting) activities.