Cat allergen peptide immunotherapy reduces CD4(+) T cell responses to cat allergen but does not alter suppression by CD4(+) CD25(+) T cells: a double-blind placebo-controlled study

BACKGROUND: We have previously described both modification of allergen immunotherapy using peptide fragments, and reduced regulation of allergen stimulated T cells by CD4(+) CD25(+) T cells from allergic donors when compared with nonallergic controls. It has been suggested that allergen immunotherapy induces regulatory T cell activity: we hypothesized that allergen peptide immunotherapy might increase suppressive activity of CD4(+) CD25(+) T cells. OBJECTIVE: To examine cat allergen-stimulated CD4 T cell responses and their suppression by CD4(+) CD25(+) T cells before and after cat allergen peptide immunotherapy in a double-blind placebo-controlled study. METHODS: Peripheral blood was obtained and stored before and after peptide immunotherapy or placebo treatment. CD4(+) and CD4(+) CD25(+) were then isolated by immunomagnetic beads and cultured with allergen in vitro. RESULTS: Comparing cells from blood taken before with that after peptide immunotherapy there was a significant reduction in both proliferation and IL-13 production by allergen-stimulated CD4+ T cells, whereas no change was seen after placebo. CD4(+) CD25(+) T cells suppressed both proliferation and IL-13 production by CD4(+) CD25(-) T cells before and after therapy but peptide therapy was not associated with any change in suppressive activity of these cells. CONCLUSION: Allergen peptide immunotherapy alters T cell response to allergen through mechanisms other than changes in CD4(+) CD25(+) T cell suppression.     

Butyrate affects differentiation,maturation and function of human monocyte-derived dendritic cells and macrophages

We studied the in vitro effects of butyric acid on differentiation, maturation and function of dendritic cells (DC) and macrophages (M(Phi)) generated from human monocytes. A non-toxic dose of butyrate was shown to alter the phenotypic differentiation process of DC as assessed by a persistence of CD14, and a decreased CD54, CD86 and HLA class II expression. The more immature differentiation stage of treated cells was confirmed further by their increased phagocytic capability, their altered capacity to produce IL-10 and IL-12, and their weak allostimulatory abilities. Butyrate also altered DC terminal maturation, regardless of the maturation inducer, as demonstrated by a strong down-regulation of CD83, a decreased expression of CD40, CD86 and HLA class II. Similarly, butyrate altered M(Phi) differentiation, down-regulating the expression of the restricted membrane antigens and reducing the phagocytic capacity of treated cells. To investigate further the mechanism by which butyrate hampers the monocyte dual differentiation pathway, we studied the effects of 1,25(OH)2D3 alone or in combination with butyrate on the phenotypic features of DC. Unlike 1,25(OH)2D3, butyrate inhibited DC -differentiation without redirecting it towards M(Phi). Combined treatment gave rise to a new cell subset (CD14(high), CD86 and HLA-DR(low)) phenotypically distinct from monocytes. These results reveal an alternative mechanism of inhibition of DC and M(Phi) differentiation. Altogether, our data demonstrate a novel immune suppression property of butyrate that may modulate both inflammatory and immune responses and support further the interest for butyrate and its derivatives as new immunotherapeutic agents.     

Distribution of human colonic dendritic cells and macrophages

To define the phenotype of intestinal dendritic cells and macrophages, resected colonic specimens were used to obtain lamina propria cell suspensions by EDTA treatment, then enzymatic digestion. The phenotype of dendritic cell-enriched suspensions was compared with that of macrophage-enriched populations by immunocytochemistry using the avidin-biotin-peroxidase (ABC) system and immunoelectron microscopy. Dendritic cells expressed HLA-DR (L243) and HLA-DQ-associated (RFD1) antigens and CD68 in a perinuclear distribution. Staining for S100 was weak or absent. Macrophages also expressed HLA markers (L243 and RFD1) and CD68. The 25F9 antigen was expressed strongly, whilst CD14 was absent from cells isolated from non-inflamed tissues. To determine their anatomic distribution, immunohistochemistry was performed using single- and double-labelling techniques (ABC ± alkaline phosphatase anti-alkaline phosphatase method). Mutually exclusive subsets of 25F9⁺ and S100⁺cells were seen: 25F9⁺ macrophages were concentrated in a band immediately beneath the luminal epithelium; S100⁺/HLA-DR⁺ dendritic cells formed a reticular network throughout the lamina propria and beneath the basement membrane of the crypts. This distribution suggests that macrophages may help regulate intestinal responses by acting as the first line of defence against the entry of luminal antigens. A breach of the macrophage ‘barrier’ by invading antigens may necessitate the recruitment of T cell responses by immunostimulatory dendritic cells.     

Pimecrolimus does not affect the differentiation,maturation and function of human monocyte-derived dendritic cells,in contrast to corticosteroids

Clinically, corticosteroids (CS) are among the first line drugs in the therapy of autoimmune and allergic diseases and potently inhibit the activation of immune cells. However, due to their pleiotropic mode of action, the prolonged use of CS is generally associated with a range of undesirable side‐effects. In this study, we compared the activity of pimecrolimus, a novel immunomodulatory drug for the treatment of inflammatory skin disorders, and the CS dexamethasone (Dex) and beta‐methasone‐valerate (β‐MSV) in different in vitro assays addressing the cytokine‐induced differentiation and maturation of monocyte‐derived dendritic cells (M‐DC), the susceptibility of M‐DC to drug‐induced apoptosis and the potency of differentiated M‐DC to induce primary T cell activation. In contrast to pimecrolimus, Dex and β‐MSV strongly induced apoptosis of M‐DC precursors if added at the start of the DC differentiation culture. Flow cytometric analysis of surviving cells on day 6 of culture showed that the expression of several DC‐specific antigens such as CD1a, CD40 and CD80 was inhibited by 50% to 80% at concentrations between 1 nm and 10 nm of either Dex or β‐MSV. Furthermore, the presence of CS during the final maturation of M‐DC inhibited the synthesis of IL‐12p70, the expression of critical DC costimulatory molecules, such as CD83 and CD86 and impaired their ability to activate primary CD4⁺ T cell proliferation. In contrast, pimecrolimus did not inhibit the LPS‐induced secretion of IL‐12, surface expression of costimulatory molecules or the maturation of M‐DC into potent stimulators of T cells. Taken together, these data indicate that pimecrolimus does not interfere with the differentiation and viability of dendritic cells and their precursors or with the function of mature M‐DC to prime naïve T lymphocytes, and thus may have a lower potential than CS to interfere with DC‐mediated immunosurveillance.     

The allergenic yeast Malassezia furfur induces maturation of human dendritic cells

BACKGROUND: The yeast Malassezia furfur (M. furfur), present in the normal microflora of human skin, can act as an allergen that incites specific IgE reactivity and T cell proliferation in atopic dermatitis (AD) patients. The role of antigen presenting dendritic cells (DCs) in the onset and maintenance of AD is not well established. OBJECTIVE: The objective of the present study was to assess whether the interaction of M. furfur with human DCs will result in DC maturation, cytokine production and lymphocyte proliferation. METHODS: Monocyte-derived dendritic cells (MDDCs) were generated from human peripheral blood. Immature MDDCs were cultured with or without M. furfur or plastic beads, and with or without CD40L stimulation. Interaction of yeast cells by MDDCs was studied by time-lapse photography and cytokines were detected in culture supernatants with ELISA. The ability of MDDCs pre-incubated with M. furfur to induce proliferation in autologous lymphocytes was measured by [(3)H]-thymidine incorporation. RESULTS: Time-lapse photography showed that the majority of immature MDDCs internalized whole M. furfur yeast cells within 1 h. The presence of M. furfur induced maturation (CD83 expression) of MDDCs, and up-regulation of the costimulatory molecules CD80 and CD86. Production of TNF-alpha, IL-1 beta and IL-18 by MDDCs increased significantly (P < 0.05 for TNF-alpha and IL-1 beta, and P < 0.01 for IL-18) after the addition of M. furfur, while IL-10 and IL-12p70 levels remained unaltered. The CD40L-stimulated IL12p70 production by MDDCs was decreased in the presence of M. furfur (P < 0.05). Finally, immature MDDCs pre-incubated with M. furfur induced a proliferative response in autologous CD14-depleted peripheral blood mononuclear cells, in a dose-dependent manner. CONCLUSION: The data indicate that immature MDDCs can internalize the opportunistic yeast M. furfur. This process was associated with MDDC maturation, production of pro-inflammatory and immunoregulatory cytokines, which might favour induction of a Th2-type immune response, and a capacity to stimulate lymphocyte proliferation. This chain of events most likely contributes to the inflammatory reaction in AD.     

Reduced in vitro T-cell responses induced by glutaraldehyde-modified allergen extracts are caused mainly by retarded internalization of dendritic cells

Although allergen-specific immunotherapy is a clinically effective therapy for IgE-mediated allergic diseases, the risk of IgE-mediated adverse effects still exists. For this reason, chemically modified allergoids have been introduced, which may destroy IgE-binding sites while T-cell activation should be retained. The aim of the study was to analyse the differences between intact allergens and differently modified/aggregated allergoids concerning their internalization as well as T-cell and basophil activation. For this purpose human monocyte-derived immature dendritic cells (DC) were incubated with Phleum pratense or Betula verrucosa pollen extract or with the corresponding allergoids, modified with formaldehyde or glutaraldehyde. After an additional maturation process, the antigen-loaded mature DC were co-cultured with autologous CD4(+) T cells. Allergenicity was tested by leukotriene release from basophils. In addition, the uptake of intact allergens and allergoids by immature DC was analysed. The proliferation of, as well as the interleukin-4 (IL-4), IL-10, IL-13 and interferon-γ production by, CD4(+) T cells which had been stimulated with glutaraldehyde allergoid-treated DC was reduced compared with CD4(+) T cells stimulated with intact allergen-treated or formaldehyde allergoid-treated DC. In line with this, glutaraldehyde-modified allergoids were more aggregated and were internalized more slowly. Furthermore, only the allergoids modified with glutaraldehyde induced a decreased leukotriene release by activated basophils. These findings suggest that IgE-reactive epitopes were destroyed more efficiently by modification with glutaraldehyde than with formaldehyde under the conditions chosen for these investigations. Glutaraldehyde-modified allergoids also displayed lower T-cell stimulatory capacity, which is mainly the result of greater modification/aggregation and diminished uptake by DC.     

Stimulation of bactericidal activity of human neutrophils by interleukin-2-activated lymphoid cells: Effect of proinflammatory cytokines

Research Institute of Hematology and Blood Transfusion, Ministry of Health of the Republic of Belarus'. Research Institute of Pulmonology and Pulmonary Tuberculosis, Ministry of Health of the Republic of Belarus', Minsk. (Presented by Academician of the Russian Academy of Medical Sciences V. I. Votyakov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 114, No. 12, pp. 641–643, December, 1992.     

Expression of CD33-related siglecs on human mononuclear phagocytes, monocyte-derived dendritic cells and plasmacytoid dendritic cells

Siglecs are sialic acid binding Ig-like lectins mostly expressed in the haemopoietic and immune systems. Amongst the 11 human siglecs, there are eight proteins highly related to CD33 which have biochemical features of inhibitory receptors, containing two conserved tyrosine-based inhibitory motifs. Five of these (CD33/siglec-3, -5, -7, -9 and -10) are expressed on circulating monocytes. Here we show that monocytes cultured to differentiate into macrophages using either GM-CSF or M-CSF retained expression of these siglecs and their levels were unaffected following stimulation with LPS. In comparison, monocyte-derived dendritic cells down-modulated siglec-7 and -9 following maturation with LPS. Plasmacytoid dendritic cells in human blood expressed siglec-5 only. On monocytes, siglec-5 was shown to mediate rapid uptake of anti-siglec-5 (Fab)2 fragments into early endosomes. This suggests, in addition to inhibitory signalling, a potential role in endocytosis for siglec-5 and the other CD33-related siglecs. Our results show that siglecs are differentially expressed on mononuclear phagocytes and dendritic cells and that some can be modulated by stimuli that promote maturation and differentiation.     

Cat allergen‐induced blood basophil reactivity in vitro predicts acute human nasal allergen challenge responses in vivo

Background Basophil histamine release (BHR) to allergen has been used as a confirmatory test to support the clinical diagnosis of allergic disease. Objective Among subjects reporting respiratory cat allergy, we hypothesized that cat‐induced BHR in vitro would predict nasal allergen challenge (NAC) response in that same individual. We therefore compared the magnitude of cat allergen‐induced BHR to NAC outcome and serological measures of cat‐specific IgE and the ratio of cat‐specific IgE to total IgE. Methods Forty‐two subjects with a history of cat allergy, positive cat puncture skin test (PST) and detectable cat‐specific IgE (>0.1 kAU/L, ImmunoCap) participated with consent. Subjects were grouped as positive or negative cat allergen‐induced BHR, with a positive result defined as the release of 20% of the total cellular histamine content. The majority of subjects also underwent a NAC with a positive result defined as 5 total sneezes. Results Subjects with a positive compared with a negative cat allergen BHR had higher cat‐specific IgE levels at 5.40±1.24 kAU/L (n=25) vs. 1.55±0.73 kAU/L (n=17, P=0.01) as well as a higher cat‐specific IgE/total IgE ratio [6.1±1.4% (n=25) vs. 1.6±0.9% (n=17, P=0.01)]. Of the 31 subjects who underwent a NAC, a positive NAC was observed in 78% (18/23) with a positive cat allergen BHR compared with 37% (3/8) with a negative cat allergen BHR, giving a positive predictive value of 78% and a negative predictive value of 63%. The diagnostic sensitivity and specificity of a positive BHR to predict a positive NAC was 86% and 50%, respectively. Conclusions and Clinical Relevance A positive cat allergen‐induced BHR is associated with higher cat‐specific IgE levels, a higher cat‐specific to total IgE ratio and is predictive of a positive cat‐induced NAC [ClinicalTrials.gov NCT00604786]. Cite this as: M. Paterniti, D. C. Kelly, J. A. Eckman, P. M. Sterba, R. G. Hamilton, B. S. Bochner, D. W. MacGlashan Jr. and S. S. Saini, Clinical & Experimental Allergy, 2011 (41) 963–969.     

CD83 monocyte-derived dendritic cells are present in human decidua and progesterone induces their differentiation in vitro

PROBLEM: Dendritic cells (DCs) play an important role in antigen presentation and immunoregulation. Modifications of the immune response during pregnancy require the participation of DC. The aim of this study was to follow-up the changes of DCs in human decidua and their correlations to progesterone (Pg) concentrations. METHODS OF STUDY: Blood leukocytes were isolated from human decidua and analyzed by flow cytometry for the expression of HLA-DR and CD83 markers. Blood monocytes were cultured to differentiate and mature to DCs in the presence of Pg, estradiol or testosterone and analyzed by flow cytometry. RESULTS: The percentage of mature DCs is increased in human decidua during the 1st trimester. When Pg is added to DCs cultured in vitro the percentage of cells expressing both markers increased in specific and dose-dependent manner. CONCLUSIONS: Pg increases the numbers of monocytic DCs locally and it may be speculated that these cells help the Th1/Th2 switching in pregnancy.     

Cord blood mesenchymal stem cells propel human dendritic cells to an intermediate maturation state and boost interleukin‐12 production by mature dendritic cells

Pathogen‐derived entities force the tissue‐resident dendritic cells (DCs) towards a mature state, followed by migration to the draining lymph node to present antigens to T cells. Bone marrow mesenchymal stem cells (MSCs) modulate the differentiation, maturation and function of DCs. In umbilical cord blood an immature MSC population was identified. Remarkably, these immature stem cells modulated DCs in a different way. Marker expression was unchanged during the differentiation of monocytes towards immature DCs (iDCs) when cocultured with cord blood MSC [unrestricted somatic stem cells (USSCs)]. The maturation to mature DCs (mDCs) was enhanced when DCs were co‐cultured with USSC, as evidenced by the up‐regulation of costimulatory molecules. Endocytosis of dextran by iDCs was hampered in the presence of USSCs, which is indicative for the maturation of iDCs. Despite this maturation, the migration of iDCs cocultured with USSCs appeared to be identical to iDCs cultured alone. However, USSCs increased the migration of mDCs towards CCL21 and boosted interleukin‐12 production. So, USSCs mature iDCs, thereby redirecting the antigen‐uptake phenotype towards a mature phenotype. Furthermore, DC maturation by lipopolysaccharide (LPS) or USSCs reflects two distinct pathways because migration was unaffected when iDCs were matured by coculture with USSCs, while it was strongly enhanced in the presence of LPS. DCs are able to discriminate the different MSC subtypes, resulting in diverse differentiation programmes.     

Differentiation and function of mouse monocyte-derived dendritic cells in steady state and inflammation

Summary: Although monocytes were originally described as precursors to all the different subpopulations of macrophages found in the steady state and formed under inflammatory and infectious conditions, recent data have demonstrated conclusively that monocytes can also differentiate into dendritic cells (DCs). Monocytes are the precursors to different subsets of DCs, such as Langerhans cells and DCs found in the lamina propria of the gastrointestinal, respiratory, and urogenital tracts. In addition, monocyte-derived DCs (moDCs), newly formed during inflammatory reactions, appear to fulfill an essential role in defense mechanisms against pathogens by participating in the induction of both adaptive and innate immune responses. In this regard, moDCs have the capacity to activate antigen-specific CD4⁺ T-cell responses and to cross-prime CD8⁺ T cells, during viral, bacterial, and parasitic infections. In addition, monocytes have been recently described as the precursors to a subset of DCs specialized in innate immunity against pathogens, named TipDCs [for TNF-α (tumor necrosis factor-α)-iNOS (inducible nitric oxide synthase)-producing DCs] that display a remarkable microbicidal activity and also provide iNOS-dependent help for antibody production by B cells. Importantly, in contrast to DCs developing in the steady state, moDCs formed during inflammatory and infectious processes are subjected to diverse soluble mediators that determine the multiple functional specificities displayed by moDCs, as a result of the remarkable developmental plasticity of monocytes. In this review, we discuss recent findings dealing with the differentiation and functional relevance of moDCs that have widened the frontiers of DC immunobiology in relation to innate and adaptive immunity and the etiology of chronic inflammatory diseases.     

Engagement of human monocyte-derived dendritic cells into interleukin (IL)-12 producers by IL-1beta + interferon (IFN)-gamma

Dendritic cells (DCs) are potent antigen-presenting cells and can induce tumour- or pathogen-specific T cell responses. For adoptive immunotherapy purposes, immature DCs can be generated from adherent monocytes using granulocyte macrophage colony stimulating factor (GM-CSF) and interleukin (IL)-4, and further maturation is usually achieved by incubation with tumour necrosis factor (TNF)-alpha. However, TNF-alpha-stimulated DCs produce low levels of IL-12. In this study, we compared the effects of TNF-alpha, interferon (IFN)-gamma, IL-1beta or IFN-gamma + IL-1beta on the phenotypic and functional maturation of DCs. Our results show that IFN-gamma, but not IL-1beta, augmented the surface expression of CD80, CD83 and CD86 molecules without inducing IL-12 production from DCs. However, IL-1beta, but not IFN-gamma, induced IL-12 p40 production by DCs without enhancing phenotypic maturation. When combined, IFN-gamma + IL-1beta treatment profoundly up-regulated the expression of CD80, CD83, CD86 and major histocompatibility complex (MHC) class II antigens. Furthermore, IFN-gamma + IL-1beta-treated DCs produced larger amounts of IL-12 and induced stronger T cell proliferation and IFN-gamma secretion in primary allogeneic mixed lymphocyte reaction (MLR) than did TNF-alpha-treated DCs. Our results show that IFN-gamma + IL-1beta induced human monocyte-derived DCs to differentiate into Th1-prone mature DCs.     

Differences in T-helper polarizing capability between human monocyte-derived dendritic cells and monocyte-derived Langerhans'-like cells

Langerhans' cells (LCs) represent a specific subset of dendritic cells (DCs) which are important for detecting and processing pathogens that penetrate the skin and epithelial barriers. The aim of our study was to explain what makes their in vitro counterparts - monocyte-derived Langerhans'-like cells (MoLCs) - unique compared with monocyte-derived dendritic cells (MoDCs). Immature MoDCs were generated by incubating peripheral blood monocytes with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4. The addition of transforming growth factor-β (TGF-β) to this cytokine cocktail resulted in the generation of MoLCs. MoLCs showed a lower expression of CD83, CD86, HLA-DR and CCR7 compared with MoDCs, regardless of their maturational status. Both immature and mature MoLCs secreted higher quantities of IL-23 compared with MoDCs and this finding correlated with a higher secretion of IL-17 in co-culture of MoLCs with allogeneic CD4(+) T cells. Mature MoLCs, which produced higher levels of IL-12 and lower levels of IL-10 compared with mature MoDCs, were more potent at inducing interferon-γ (IFN-γ) production by CD4(+) T cells in the co-culture system. In conclusion, the finding that mature MoLCs stimulate stronger T-helper 1 and T-helper 17 immune responses than mature MoDCs, makes them better candidates for use in the preparation of anti-tumour DC vaccines.     

IL-1 beta induces dendritic cells to produce IL-12

The cytokine IL-12, a product of dendritic cells (DC), plays a major role in cellular immunity, notably by inducing lymphocytes to produce IFN-gamma. Microbial products, T cell signals and cytokines induce the production of IL-12. Here, IL-1 beta is identified as a new IL-12-inducing agent, acting conjointly with CD40 ligand (CD40L) on human monocyte-derived DC in vitro. The effects of IL-1 beta were dose dependent, specifically blocked by neutralizing antibodies, and were observed both in immature and mature DC. Immature DC secreted more IL-12 than mature DC, but the effects of IL-1 beta were not due to a block of DC maturation as determined by analysis of DC surface markers. The mechanisms of action of IL-1 beta could be contrasted to that of other inducers of IL-12 such as IFN-gamma and lipopolysaccharide (LPS). Either IL-1 beta or IFN-gamma co-induced IL-12 with CD40L but conjointly, IL-1 beta, CD40L and IFN-gamma synergized, inducing very high levels of IL-12. The effects of IL-1 beta differed from those of LPS in that IL-1 beta, unlike LPS, could not induce IL-12 solely after IFN-gamma priming; and when combined with CD40L, IL-1 beta, unlike LPS, induced little IL-10. The mechanism of action of IL-1 beta involves IL-12 alpha mRNA up-regulation, and we show that the combination of CD40L and IL-1 beta induces high levels of IL-12 alpha and IL-12 beta mRNA in DC. Altogether, these results delineate a new mechanism linking adaptive and innate immune responses for the regulation of IL-12 production in DC and for the role of IL-1 beta in the development of cellular immunity.     

Activation of human neonatal monocyte-derived dendritic cells by lipopolysaccharide down-regulates birch allergen-induced Th2 differentiation

Epidemiological studies describe an inverse association between the level of environmental endotoxin exposure during infancy and the prevalence of allergic disease in children. To study the effect of lipopolysaccharide (LPS) and lipopeptide Pam3Cys signaling via Toll-like receptor (TLR)4 and TLR2 on dendritic cells (DC), respectively, on birch allergen-induced T cell differentiation, cord blood monocyte-derived DC were exposed to birch allergen extract alone or in combination with LPS or Pam3Cys and thereafter co-cultured with naive autologous T cells. We demonstrate that birch allergen alone induced high levels of IL-13 from neonatal T cells, whereas the production of IL-5 and IFN-gamma was modest. Stimulation of DC with birch allergen together with LPS but not Pam3Cys resulted in a decreased IL-13 production by T cells compared to birch allergen alone. Furthermore, birch allergen together with LPS induced increased up-regulation of activation markers expressed on the surface and production of cytokines from DC relative to stimulation with birch allergen alone. Finally, birch allergen partially suppressed both LPS- and Pam3Cys-induced DC maturation. Our results indicate that concomitant TLR4 stimulation during the initial phase of immune activation to birch allergen in infants may inhibit the development of a T helper 2-type response.     

Levamisole enhances immune response by affecting the activation and maturation of human monocyte-derived dendritic cells

The primary aim of this study was to evaluate the role of natural killer (NK) cells on antigen-specific adaptive immune responses. After analysing the mechanism of impaired adaptive immune responses of NK-depleted mice, an immune interventional approach was developed to restore adaptive immunity in NK-depleted mice. NK cells were depleted from mice by administration of anti-asialo GM1 antibody (100 mul/mouse), twice, at an interval of 48 h. Hepatitis B surface antigen (HBsAg) was administered intraperitoneally to normal C57BL/6 mice (control mice) and NK-depleted mice. The levels of antibody to HBsAg (anti-HBs) in the sera and HBsAg-specific lymphocytes in the spleen were assessed. The functions of T lymphocytes, B lymphocytes and dendritic cells (DCs) were evaluated in vitro. HBsAg-pulsed DCs were prepared by culturing spleen DCs with HBsAg for 48 h and administered once to NK-depleted mice. The levels of anti-HBs in the sera and HBsAg-specific lymphocytes were significantly lower in NK-depleted mice compared with control mice (P < 0.05). The functions of T and B lymphocytes were similar between control mice and NK-depleted mice. However, the functions of spleen DC and liver DC were significantly lower in NK-depleted mice compared with control mice (P < 0.05). Administration of HBsAg-pulsed DCs, but not HBsAg, induced HBsAg-specific humoral and cellular immune responses in NK-depleted mice. Our study suggests that cross-talk between NK cells and DCs regulates the magnitude of adaptive immunity. In addition, antigen-pulsed immunogenic DCs represent potent immune modulator even if subjects with diminished innate immunity.     

A variety of cytokines and immunologically relevant surface molecules are expressed by normal human skeletal muscle cells under proinflammatory stimuli

Muscle is an attractive target for gene therapy and for immunization with DNA vaccines and is also the target of immunological injury in myositis. It is important therefore to understand the immunologic capabilities of muscle cells themselves. In this study, we show that proinflammatory stimuli induce the expression of other cytokines such as IL-6, transforming growth factor-beta (TGF-β), and granulocyte-macrophage colony-stimulating factor (GM-CSF) by muscle cells themselves, as well as the up-regulation of human leucocyte antigen (HLA) class I, class II and intercellular adhesion molecule-1 (ICAM-1). Thus, muscle cells have an inherent ability to express and respond to a variety of cytokines and chemokines. The levels of HLA class I, class II and ICAM-1 in inflamed muscle may be affected by the secreted products of the stimulation.