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Results for “antigen expression and secretion”

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PubMed1987

Cell type specific expression of pre S 1 antigen and secretion of hepatitis B virus surface antigen. Brief Report.

Production of the three hepatitis B surface (HBs) proteins was studied in a hepatoma cell line (PLC/PRF/5) and two HBs antigen secreting cell lines (HeLa and mouse L-cells), which had been transfected by a viral genome isolated by molecular cloning from PLC/PRF/5 chromosomal DNA. The DNA used for transfection contains the HBs-specific promoters and the enhancer which regulate the expression of HBs genes in the transfected cell lines. All three cell lines expressed well the small and middle HBs protein, but the larger pre S 1 containing protein was barely detectable in the L-cell. In vivo growth of the transfected HeLa cell as nude mouse tumour increased pre S 1 expression and suppressed secretion of HBsAg.

Animals↗

PubMed1992

Immunity to B16 melanoma in mice immunized with IL-2-secreting allogeneic mouse fibroblasts expressing melanoma-associated antigens.

Co-presentation of weak tumour-associated antigens along with strongly immunogenic determinants leads to the development of an anti-tumour immune response in recipients syngeneic with the tumour. Tumour immunity develops in mice immunized with tumour cells modified by the introduction of cDNA for interleukin-2 (IL-2). Here, we report the anti-tumour response following immunization with an IL-2-secreting cell construct that expresses tumour-associated antigens, along with allogeneic major histocompatibility antigens. The construct was prepared by transfecting LM(TK-) mouse fibroblasts (H-2k) with genomic DNA from B16 melanoma cells syngeneic in C57BL/6J mice (H-2b). Transfectants expressing melanoma-associated antigens (MAA) were then infected with an expression-competent retroviral vector containing a cDNA specifying human IL-2. Cytotoxicity toward B16 cells was detected for as long as 5 months in both spleen and macrophage cell populations in C57BL/6J mice immunized with the IL-2-secreting cells. Mice immunized with non-IL-2-secreting, MAA-positive allogeneic cells developed melanoma immunity as well, but to a lesser extent. Immunity to 2 tumour-cell lines expressing the H-2d haplotype and to YAC-1 cells was detected in peritoneal macrophages, but not in spleen cells from C57BL/6J mice immunized with the cell construct, indicating that the response to B16 cells was only partially specific. C57BL/6J mice immunized with the IL-2-secreting cell construct survived significantly longer, following an injection of viable B16 cells, than mice in various control groups. The contribution of allogeneic antigens to the melanoma immunity was indicated by the failure of mice syngeneic with LM(TK-) cells to develop melanoma immunity following immunization with non-IL-2-secreting, MAA-positive cell constructs. The formation of IL-2 partially compensated for the lack of allogeneic antigens.

Animals↗

PubMed1986

Expression and secretion of hepatitis B viral surface antigen in E. coli.

Hepatitis B viral surface antigen (HBsAg) gene was subcloned into the BglII site of Bacillus licheniformis penicillinase (penP) gene of secretory vector pJP104. Expression and secretion of HBsAg protein was achieved by the E. coli CS412 carrying the plasmid pJPS2 in which the penP:HBsAg hybrid gene was under the control of two promoters, lipoprotein (lpp) and penP, spaced 450 bases apart. The secreted form of HBsAg encoded by the hybrid penP: HBsAg gene of plasmid pJPS2 was purified by immunoaffinity chromatography and found to be a 25 kilodalton protein.

Escherichia coli↗

PubMed1996

Antigen binding differences between secreted and cell surface expressed rheumatoid factor derived from inflamed synovium.

OBJECTIVE: Rheumatoid factor (RF) is the predominant autoantibody in rheumatoid arthritis (RA). but its role in the pathogenesis of RA remains unclear. We hypothesized that surface RF (sRF) expressed on antigen presenting B cells (B-APC) might have different binding specificities than secreted RF. METHODS: We examined RF binding in a novel RF antigen capture enzyme linked immunoassay (ACE) that mimicked sRF binding, and compared it with a direct binding enzyme linked immunoassay (DBE) that mimicked secreted RF. RESULTS: Significant differences in binding characteristics by the same rheumatoid synovial cell (RSC) derived monoclonal RF (mRF) were observed between the ACE and the DBE. For example, several mRF that demonstrated the classical Ga binding pattern (binding to IgG1, 2, and 4) in the DBE showed considerable binding to selected IgG3 proteins in the ACE; and several mRF that bound only to rabbit IgG in DBE bound to human IgG in the ACE. CONCLUSION: These RF reactivity differences may be attributed to conformational modifications in the RF and IgG molecules that expose different epitopes or altered binding sites depending on the physical state of the antibody and/or antigen and may be important pathogenically.

Animals↗

PubMed1990

Enhanced expression and secretion of an epithelial membrane antigen (MA5) in a human mucinous breast tumor line (BT549).

The mouse monoclonal antibody MA5, generated versus a membrane-enriched extract of breast cancer metastatic to liver, detects one or two high molecular weight species (greater than 200 kD) in breast tumor membranes, human milk fat globule membranes, and various breast tumor cell lines. From comparative studies of five breast carcinoma lines (BT20, BT549, MCF-7, T47D, and ZR75-1), as well as an epithelial line established from milk (HBL-100), we report the stimulation of expression of MA5-reactive antigen in a mucinous breast tumor cell line (BT549) through the use of a culture medium supplemented with charcoal-absorbed fetal calf serum, insulin, and hydrocortisone. Large amounts of aggregated MA5-reactive antigen are secreted into the culture medium and can be recovered from the media for further purification by centrifugation. These findings suggest that BT549 cells, grown in the special nutritive medium, may be useful in providing an ample source of epithelial membrane antigen (also termed polymorphic epithelial mucin) for standardization of clinical assay protocols, as well as provide a model system for studies of the regulation of expression for this class of antigens in breast carcinoma.

Adenocarcinoma, Mucinous↗

PubMed1996

Antigen presentation by Leishmania mexicana-infected macrophages: activation of helper T cells by a model parasite antigen secreted into the parasitophorous vacuole or expressed on the amastigote surface.

Leishmania are protozoan parasites which invade mammalian macrophages and multiply as amastigotes in phagolysosomes (parasitophorous vacuoles). Using L. mexicana and bone marrow-derived macrophages (BMM), the question is addressed whether infected BMM induced to express major histocompatibility complex class II molecules can present defined antigens to specific T helper type 1 cells. As a model antigen, a membrane-bound acid phosphatase (MAP), a minor protein associated with intracellular vesicles in amastigotes, was either overexpressed at the surface of the parasites or overexpressed in a soluble form leading to antigen secretion into the parasitophorous vacuole. Presentation of MAP epitopes by these three types of amastigotes was then compared for macrophages containing live parasites or amastigotes inactivated by drug treatment. It is shown that surface-exposed and secreted MAP can be efficiently presented to T cells by macrophages harboring live amastigotes. Therefore, the parasitophorous vacuole communicates by vesicular membrane traffic with the plasmalemma of the host cell. The intracellular MAP of wild-type cells or the abundant lysosomal cysteine proteinases are not or only inefficiently presented, respectively. After killing of the parasites, abundant proteins such as overexpressed MAP and the cysteine proteinases efficiently stimulate T cells, while wild-type MAP levels are not effective. We conclude that intracellular proteins of intact amastigotes are not available for presentation, while after parasite inactivation, presentation depends on antigen abundance and possibly stability. The cell biological and possible immunological consequences of these results are discussed.

Animals↗

PubMed1996

Nutritional support for adaptation to radiation-induced suppression of mucosal immunity in the intestine of the rat.

Appropriate enteral nutrition provided immediately after injury or trauma to the gastrointestinal tract may limit or reverse damage to the mucosal barrier. In this regard, diets containing amino acids, such as arginine and glutamine, or fish oil have been identified as beneficial. This report assesses the role of amino acids as "essential nutrients" in the repair of intestinal mucosa damaged by gamma radiation. Rats were used experimentally to test the hypothesis that the recovery of the immune responses in the intestinal mucosa, which are suppressed by radiation, can be improved by feeding an elemental amino acid diet, referred to hereafter as the diet, immediately after irradiation. The objective was to assess the impact of the diet on the expression of type I hypersensitivity or anaphylaxis in the jejunal mucosa. The local expression of this immunological response, which involves several radiosensitive cell types, was studied in rats immunized by oral infection with the nematode parasite, Trichinella spiralis. Rats that recover from infection become immunized and their small intestine undergoes anaphylaxis when subsequently challenged with parasite-derived antigen. This hypersensitivity response is expressed, in part, as Cl- secretion and can be observed in vitro or in vivo. When challenge is provided by a secondary inoculum of infective T. spiralis larvae, Cl- secretion is accompanied by fluid secretion and by the rapid expulsion of the parasite from the intestine. Immunized rats maintained on a stock diet and exposed to 7 Gy of total-abdominal irradiation from a cobalt-60 gamma-ray source failed to express antigen-induced Cl- secretion fully for up to 14 days postirradiation, and rejection of the parasite was suppressed for at least 30 days postirradiation. The suppression of immune responsiveness is associated with the disappearance of intestinal mucosal mast cells, which normally trigger the anaphylactic response. When rats are maintained on the diet after irradiation, the capacity to reject the parasite remains suppressed. However, the ability to express anaphylaxis-mediated Cl- secretion returns by 3 days postirradiation. The quick, diet-supported recovery of antigen-induced Cl- secretion occurs despite the continued absence of mast cells. Although the recovery of anaphylaxis-mediated responses suppressed by irradiation is only partial, our experimental results underscore the potential for enhancing the recovery process through nutritional support.

Amino Acids↗

PubMed2001

Efficient tumor regression induced by genetically engineered tumor cells secreting interleukin-2 and membrane-expressing allogeneic MHC class I antigen.

PURPOSE: To analyze the immunotherapeutic potentials of genetically engineered tumor cells secreting IL-2 and a membrane-expressing allogeneic MHC class I molecule Kb in a murine hepatoma model. METHODS: In order to express both genes in coordination in the target cells, we constructed a polycistronic retroviral vector containing Kb, IL-2, and NeoR genes using two internal ribosome entry sites (IRES). Tumor growth was carried out by implantation of transduced tumor cells into mouse, while anti-tumor effects were demonstrated by the treatment of established tumors. The infiltrated cells were analyzed by immunohistochemistry. RESULTS: The combined effect of IL-2 secretion and alloantigen expression on immunostimulation was demonstrated by the rejection of transduced tumor cells. In the treatment of established tumors, the Kb/IL-2 co-expressing tumor cells induced strong anti-tumor immunity, superior to that induced by the single gene-transduced cells. The increased diversity of infiltrated cell types in tumor sites indicated that both a specific and non-specific immune response had been activated. CONCLUSION: Our study provides evidence that tumor cells with IL-2 secretion and membrane-expression of allogeneic MHC class I antigen are capable of inducing both strong tumor rejection and immunity.

Animals↗

PubMed2005

Helicobacter pylori outer membrane proteins and gastroduodenal disease.

BACKGROUND AND AIMS: A number of Helicobacter pylori outer membrane proteins (OMPs) undergo phase variations. This study examined the relation between OMP phase variations and clinical outcome. METHODS: Expression of H pylori BabA, BabB, SabA, and OipA proteins was determined by immunoblot. Multiple regression analysis was performed to determine the relation among OMP expression, clinical outcome, and mucosal histology. RESULTS: H pylori were cultured from 200 patients (80 with gastritis, 80 with duodenal ulcer (DU), and 40 with gastric cancer). The most reliable results were obtained using cultures from single colonies of low passage number. Stability of expression with passage varied with OipA > BabA > BabB > SabA. OipA positive status was significantly associated with the presence of DU and gastric cancer, high H pylori density, and severe neutrophil infiltration. SabA positive status was associated with gastric cancer, intestinal metaplasia, and corpus atrophy, and negatively associated with DU and neutrophil infiltration. The Sydney system underestimated the prevalence of intestinal metaplasia/atrophy compared with systems using proximal and distal corpus biopsies. SabA expression dramatically decreased following exposure of H pylori to pH 5.0 for two hours. CONCLUSIONS: SabA expression frequently switched on or off, suggesting that SabA expression can rapidly respond to changing conditions in the stomach or in different regions of the stomach. SabA positive status was inversely related to the ability of the stomach to secrete acid, suggesting that its expression may be regulated by changes in acid secretion and/or in antigens expressed by the atrophic mucosa.

Adenocarcinoma↗

PubMed2002

Dysfunctional and short-lived subsets in monocyte-derived dendritic cells from patients with advanced cancer.

Dendritic cells (DCs) are antigen-presenting cells specialized for the induction of the primary T-cell response. Tumor immunotherapy using DCs loaded with tumor antigens is under way for patients with several types of advanced malignancies. In this study, DC-like cells (Mo-DCs) were generated from peripheral blood monocytes with granulocyte-macrophage colony-stimulating factor and interleukin-4. The antigen-presenting abilities, including capture of apoptotic tumor cells, IL-12 secretion, expression of antigen-presentation-related molecules (HLA-ABC, HLA-DR, and CD80), and mixed leukocyte reaction, of Mo-DCs from 37 patients with advanced cancer (pMo-DCs) were compared to those of 20 healthy volunteers (hMo-DCs). Seven days after the initial culture, no significant difference was found in either the number or the size of Mo-DC-forming colonies between the two groups. However, most of the antigen-presenting abilities of pMo-DCs were weaker than those of hMo-DCs on day 7. On day 14, both number and size of colonies were significantly decreased in pMo-DCs but not in hMo-DCs. Interestingly, the antigen-presenting abilities of the remaining pMo-DCs gradually strengthened with time and by day 14 no significant difference was observed between pMo-DCs and hMo-DCs. These results indicate that pMo-DCs contain dysfunctional and short-lived Mo-DC subsets.

Aged↗

PubMed1998

Expression, characterization and serological reactivity of a 41 kDa excreted-secreted antigen (ESA) from Toxoplasma gondii.

A Toxoplasma gondii tachyzoite expression library was screened with immune sera from T. gondii infected patients. Among others, one gene product reacted strongly with human sera and was further investigated. The gene called B10 was shown to encode a 41 kDa antigen. The complete genomic nucleotide sequence of the B10 protein has been analysed and was shown to contain one intron with conserved splice junctions. Southern blot analysis indicated that B10 is a single-copy gene. The corresponding 1.5 kb cDNA encodes a 318 amino acid sequence of mainly hydrophilic character with a putative signal sequence of 19 amino acids and no further trans-membrane domain. Immunofluorescence assays and immunoblots with a preparation of excreted-secreted antigens (ESA) suggested that the native protein is secreted into the parasitophorous vacuole and its delimiting membrane, indicating that B10 is a member of the ESA family of T. gondii. Recombinant B10 protein exhibited a strong reactivity with human serum samples both in ELISA and in immunoblots.

Amino Acid Sequence↗

PubMedDate not supplied

Acquired alteration in the expression of blood groups in a patient with sideroblastic anemia and chronic renal failure.

A patient with well-differentiated lymphocytic lymphoma in remission presented with renal failure, sideroblastic anemia, and an acquired diminution in the expression of A antigen on his red cells. Other red cell antigens (H, M, i, and I) also were expressed weakly. Lewis antigen was expressed only in secretions. The diminished expression of the A antigen could not be accounted for by diminution in the specific glycosyl transferases responsible for its expression, since the activity in the serum of both the H enzyme (alpha 1 leads to 2 fucosyltransferase) and the A enzyme (alpha 1 leads to 3 N-acetylgalactosaminyltransferase) was not diminished. When sialic acid was removed by enzymatic treatment, the expression of the A and i antigens was augmented markedly, suggesting that the sialic acid may have altered the expression or detection of the antigens. This abnormality was probably related to dysplasia of the bone marrow which was otherwise manifest by ringed sideroblasts, unsegmented megakaryocytes, and diminished growth in vitro.

ABO Blood-Group System↗

PubMed1984

Identification and characterization of a monoclonal antibody to an antigen expressed on activated macrophages.

A hybridoma clone secreting a monoclonal antibody, designated MA158.2, that reacts with an antigen expressed on lymphokine-treated macrophages was produced by fusion of mouse myeloma cells with rat spleen cells immunized against C57BL/6 peritoneal macrophages rendered tumoricidal in vitro by incubation with the lymphokine macrophage-activating factor. The specificity of the antibody for activated macrophages and lack of reactivity with histologically diverse cell types was determined by radioimmune indirect binding and flow cytometry. MA158.2 antibody binds to mouse peritoneal macrophages elicited by nonspecific inflammatory agents and to tumoricidal macrophages elicited with Corynebacterium parvum. Resident peritoneal, splenic, and alveolar macrophages were only weakly positive. Several macrophage cell lines (P388D1, WEH1-231, J774, RAW 264.7), murine fibroblasts, and neutrophils did not bind detectable amounts of MA158.2. Radioimmune indirect binding analysis demonstrated that cell suspensions prepared from C57BL/6 mouse spleen, thymus, and lymph node as well as polymorphonuclear leukocytes, lymphocytes, and T- and B-cell murine lymphomas were MA158.2 negative. Expression of the reactive antigen on the macrophage cell surface was enhanced 3-fold following in vitro activation of elicited macrophages with macrophage-activating factor and the kinetics of activation to the tumoricidal state paralleled the increased expression of the antigen recognized by MA158.2. MA158.2 is a rat IgG2a antibody containing a single specific heavy and light chain that does not detect a polymorphic determinant. This monoclonal antibody will be a useful tool for monitoring the efficacy of agents in activating murine macrophages to the tumoricidal state and in analyzing the sequence of biochemical events that culminate in macrophage activation.

Animals↗

PubMed2000

Protection against respiratory syncytial virus (RSV) elicited in mice by plasmid DNA immunisation encoding a secreted RSV G protein-derived antigen.

Plasmid vectors encoding two different variants, one cytoplasmic and one secreted version, of a candidate vaccine BBG2Na to respiratory syncytial virus (RSV), were constructed and evaluated in a nucleic acid vaccination study. The two different vectors, which employed the Semliki Forest virus gene amplification system, were found to express BBG2Na appropriately in in vitro cell cultures. Immunisation of mice with the plasmid vectors elicited significant serum anti-BBG2Na IgG responses only in the mice receiving the plasmid encoding the secreted version of BBG2Na. Consistent with antibody induction data, sterilising lung protection against RSV-A challenge was also only observed in this group. These results indicate that the targeting of antigen expression (intracellular versus secreted) would be an important factor to consider in the design of nucleic acid vaccines.

Animals↗

PubMed1981

Induction of hepatitis B surface antigen in human hepatoma-derived cell lines.

Cultures of two human hepatoma cell lines were examined for expression of hepatitis B virus surface antigen (HBsAg). The PLC/PRF/5 cells secreted HBsAg continuously into the culture medium, whereas Mahlavu cells did not secrete the antigen. However, cytoplasmic antigen was detected in a low percentage (less than 5%) of the Mahlavu cells. The expression of HBsAg also was assayed in cultures treated wtih dexamethasone (DXM), 5-iodo-2'-deoxyuridine (IdUrd), or both. The results demonstrated that: (i) DXM stimulated secretion of HBsAg by PLC/PRF/5 cells but not by Mahlavu cells; (ii) the percentage of Mahlavu cells expressing cytoplasmic HBsAg was not increased in any cultures if the medium was replaced at 24 t0 48 h intervals but was increased approx. fivefold within 4 days in cultures treated with DXM or IdUrd/DXM if the medium was not changed. However, no increase was noted in the intensity of the immunoperoxidase stain of PLC/PRF/5 cells that expressed cytoplasmic antigen in any DXM cultures; (iii) HBsAg expression was stimulated to a lesser extent in IdUrd/DXM cultures than in DXM cultures and was not enhanced in IdUrd cultures. Thus, DXM enhanced secretion of HBsAg by PLC/PRF/5 cells within 24 h and, after a delay, enhanced expression of cytoplasmic antigen by Mahlavu cells. However, antigen secretion by Mahlavu cells evidently was blocked.

Carcinoma, Hepatocellular↗

PubMed2006

Prostate specific antigen expression does not necessarily correlate with prostate cancer cell growth.

PURPOSE: The antiproliferative effects of pharmacological agents used for androgen ablative therapy in prostate cancer, including goserelin, bicalutamide and cyproterone acetate (Fluka Chemie, Buchs, Switzerland), were tested in vitro. It was determined whether they affected prostate specific antigen mRNA and protein expression independent of growth inhibition. MATERIALS AND METHODS: Goserelin, bicalutamide (AstraZeneca, Zug, Switzerland) and cyproterone acetate were added to prostate specific antigen expressing, androgen dependent LNCaP and androgen independent C4-2 cell line (Urocor, Oklahoma City, Oklahoma) cultures. Proliferation was determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide assay (Roche, Mannheim, Germany). Prostate specific antigen mRNA expression was assessed by quantitative real-time polymerase chain reaction. Secreted prostate specific antigen protein levels were quantified by microparticle enzyme-immunoassay. RESULTS: Goserelin inhibited cell growth and prostate specific antigen protein secretion in LNCaP and C4-2 cells. Prostate specific antigen mRNA expression was not decreased. Bicalutamide did not affect cell growth or prostate specific antigen mRNA expression in LNCaP or C4-2 cells, although it significantly decreased prostate specific antigen protein secretion in LNCaP and to a lesser extent in C4-2 cells. Cyproterone acetate decreased the growth of C4-2 but not of LNCaP cells. It did not affect prostate specific antigen mRNA or protein expression in either cell line. CONCLUSIONS: Prostate specific antigen expression does not necessarily correlate with cell growth. Without a substantial effect on cell growth bicalutamide lowers prostate specific antigen synthesis, whereas cyproterone acetate decreases cell growth with no effect on prostate specific antigen secretion. Prostate specific antigen expression may be influenced by growth inhibition but also by altered mRNA and protein levels depending on the agent, its concentration and the cell line evaluated. For interpreting clinical trials prostate specific antigen is not necessarily a surrogate end point marker for a treatment effect on prostate cancer cell growth.

Androgen Antagonists↗

PubMed1988

The expression of glycoproteins in the extracellular matrix of the cellular slime mold Dictyostelium discoideum.

In this report we examine the accumulation of glycoconjugates in the extracellular medium and insoluble matrices surrounding developing cells of the cellular slime mold Dictyostelium discoideum. Conditions were employed which permitted advanced development (slug stage and beyond) in suspension culture. Under these conditions, up to one-third of the total culture protein appeared as non-sedimentable, extracellular material over the course of 48 h of incubation. Most of the secreted molecules expressed carbohydrate antigens (glycoantigens) as detected by Western blotting, using a panel of six monoclonal antibodies. Since the glycoantigens are secreted, immunoelectron microscopy was used to localize the glycoantigens in the extracellular matrices surrounding normally developing cells, including the slime sheath, stalk tube, inner spore coat, outer spore coat, and intercellular fluid between spores. Each glycoantigen had a characteristic distribution, and each extracellular matrix space contained a unique combination of glycoantigens. Thus, although each of these matrices (except inter-spore fluid) contains cellulose as a primary component, they could be distinguished on the basis of their glycoantigen and, by inference, glycoprotein compositions. Furthermore, there were differences between anterior and posterior regions of both slime sheaths and stalk tubes. These observations show that secretion as detected in suspension culture occurs under normal conditions as a part of the process of depositing extracellular matrices around the cells. The distributions show that the cell aggregate positionally regulates the expression and deposition of secretory glycoproteins; the resultant patterns of expression of unique protein-linked carbohydrate structures imply a functional role in matrix organization and possibly cell activity which can now be explored.

Antibodies, Monoclonal↗

PubMed1999

The effects of dexamethasone, cyclosporine, and vitamin D(3) on the activation of dendritic cells stimulated by haptens.

By their potent antigen-presenting function, dendritic cells (DCs) play a crucial role in the initiation of T cell-mediated immunity, including allergic contact hypersensitivity. To acquire such potent antigen-presenting ability, DCs in tissue must be activated, with increased expression of costimulatory molecules. Recent progress in DC biology has demonstrated that DCs can be activated via a variety of substances, e.g. various cytokines, CD40 ligand, bacterial products, and haptens, to increase their antigen-presenting ability, probably by different mechanisms. Therefore, in this study, to elucidate the mechanisms underlying the efficacy of the immunosuppressive drugs dexamethasone (DEX), cyclosporine A (CY), and vitamin D(3) (Vit D3) in the modulation of allergic contact hypersensitivity reactions, we examined the effects of these drugs on CD86 and HLA-DR antigen expression and TNFalpha secretion by monocyte-derived DCs stimulated with two representative haptens, NiCl(2) and DNCB, in vitro. The augmented expression of CD86 induced by NiCl(2) and DNCB was significantly suppressed by DEX at concentrations in the range 10(-8) to 10(-5) M, which include concentrations less than its therapeutically effective concentration of 10(-7) M. Vit D3 also significantly suppressed NiCl(2)- and DNCB-induced augmented expression of CD86, at concentrations in the ranges 10(-9) to 10(-7) M and 10(-10) to 10(-7) M, respectively. In contrast, significant suppressive effects of CY on the NiCl(2)- or DNCB-induced augmented expression of CD86 were seen only at concentrations in the range 10(-6) to 10(-5) M, which are more than ten times higher than its effective concentration for T cell suppression. The augmented expression of HLA-DR antigen, which was only induced by stimulation with NiCl(2), was resistant to treatment with these three drugs. Only DEX suppressed HLA-DR antigen expression at 10(-5) M. TNFalpha secretion by stimulated DCs was suppressed by DEX and Vit D3, although their effects were not statistically significant. Thus DEX and Vit D3 could modulate allergic contact dermatitis by their clearly demonstrated suppressive effects on the activation of DCs by haptens.

Antigens, CD↗