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G J Adema

Publications and source records attributed to G J Adema.

At least 19 recordsLinked to original sources
PubMed2006

Efficient loading of dendritic cells following cryo and radiofrequency ablation in combination with immune modulation induces anti-tumour immunity.

Dendritic cells (DC) are professional antigen-presenting cells that play a pivotal role in the induction of immunity. Ex vivo-generated, tumour antigen-loaded mature DC are currently exploited as cancer vaccines in clinical studies. However, antigen loading and maturation of DC directly in vivo would greatly facilitate the application of DC-based vaccines. We formerly showed in murine models that radiofrequency-mediated tumour destruction can provide an antigen source for the in vivo induction of anti-tumour immunity, and we explored the role of DC herein. In this paper we evaluate radiofrequency and cryo ablation for their ability to provide an antigen source for DC and compare this with an ex vivo-loaded DC vaccine. The data obtained with model antigens demonstrate that upon tumour destruction by radiofrequency ablation, up to 7% of the total draining lymph node (LN) DC contained antigen, whereas only few DC from the conventional vaccine reached the LN. Interestingly, following cryo ablation the amount of antigen-loaded DC is almost doubled. Analysis of surface markers revealed that both destruction methods were able to induce DC maturation. Finally, we show that in situ tumour ablation can be efficiently combined with immune modulation by anti-CTLA-4 antibodies or regulatory T-cell depletion. These combination treatments protected mice from the outgrowth of tumour challenges, and led to in vivo enhancement of tumour-specific T-cell numbers, which produced more IFN-gamma upon activation. Therefore, in situ tumour destruction in combination with immune modulation creates a unique, 'in situ DC-vaccine' that is readily applicable in the clinic without prior knowledge of tumour antigens.

Animals↗
PubMed2006

Vaccination of colorectal cancer patients with CEA-loaded dendritic cells: antigen-specific T cell responses in DTH skin tests.

BACKGROUND: Dendritic cells (DCs) are the professional antigen-presenting cells of the immune system. As such they are currently used in clinical vaccination protocols in cancer patients. PATIENTS AND METHODS: We evaluated the ability of mature DCs pulsed with carcinoembryonic antigen (CEA)-peptide to induce CEA-specific T cell responses in patients with resectable liver metastases from colorectal cancer. CEA-specific T cell reactivity was monitored in peripheral blood, biopsies of vaccination sites and post-treatment DTH skin tests, and when available also in resected abdominal lymph nodes and tumor tissue. RESULTS: Ten patients were vaccinated intradermally and intravenously with CEA-peptide pulsed mature DCs three times prior to resection of liver metastases. High numbers of CEA-specific T cells were detected in post-treatment DTH biopsies in seven out of 10 patients, which produced high amounts of interferon (IFN)-gamma upon stimulation with CEA-loaded target cells. These responses were not found in biopsies of first vaccination sites, indicating a de novo T cell induction or at least a strong potentiation by the vaccine. In addition, CEA-specific T cells were detected in a resected lymph node in one patient, but not in peripheral blood or tumor tissue. CONCLUSIONS: Vaccination with CEA-peptide loaded mature DCs induced potent CEA-specific T cell responses in advanced colorectal cancer patients. In this study, antigen-specific T cell responses were readily detected in DTH skin tests, much less in abdominal lymph nodes, and not in peripheral blood and tumor tissue.

Adult↗
PubMed2005

Dendritic cells, Fc{gamma} receptors, and Toll-like receptors: potential allies in the battle against rheumatoid arthritis.

Recent findings suggest an important role for Fcgamma receptors and Toll-like receptors expressed by dendritic cells (DC) in the pathogenesis of rheumatoid arthritis (RA). Possibly, DC behaviour might be tuned to counteract the misbalanced immune system in RA. Understanding the precise mechanisms that determine the skewed immune response in RA may provide new clues for the therapeutic use of DC in RA.

Arthritis, Rheumatoid↗
PubMed2004

Increased expression of CCL18, CCL19, and CCL17 by dendritic cells from patients with rheumatoid arthritis, and regulation by Fc gamma receptors.

BACKGROUND: Dendritic cells (DC) have a role in the regulation of immunity and tolerance, attracting inflammatory cells by the production of various chemokines (CK). Fc gamma receptors (Fc gamma R) may be involved in regulation of the DC function. OBJECTIVE: To assess the expression of CK by immature (iDC) and mature DC (mDC) and its regulation by Fc gamma R in patients with RA and healthy donors (HC). METHODS: Expression of CK by DC from patients with RA and from HC was determined by real time quantitative PCR and ELISA. DC were derived from monocytes following standardised protocols. To study the potential regulation by Fc gamma R, iDC were stimulated with immune complexes (IC) during lipopolysaccharide (LPS) induced maturation. The presence of CK was studied in synovial tissue from patients with RA, osteoarthritis, and healthy subjects by RT-PCR and immunohistochemistry. RESULTS: iDC from patients with RA had markedly increased mRNA levels of the CK CCL18 and CXCL8. Upon maturation with LPS, expression of CCL18, CCL19, CXCL8, CCL3, and CCL17 increased dramatically, reaching significantly higher levels in patients with RA. Monocytes failed to express these CK, except for CXCL8 and CCL3. IC-mediated triggering of the Fc gamma R on DC from patients with highly active RA down regulated all CK, whereas the reverse was seen when DC from patients with low disease activity and healthy donors were stimulated. CCL18 was significantly increased in RA synovial tissue. CONCLUSION: Increased CK expression by DC was found in patients with RA. This expression is partly regulated by Fc gamma R triggering and results in an inhibitory DC subtype in RA upon Fc gamma R-mediated triggering.

Arthritis, Rheumatoid↗
PubMed2004

High production of proinflammatory and Th1 cytokines by dendritic cells from patients with rheumatoid arthritis, and down regulation upon FcgammaR triggering.

OBJECTIVE: To assess whether DC from RA produce altered cytokine levels and whether this is regulated by triggering of Fc gamma receptors (FcgammaR). METHODS: The production of proinflammatory (TNFalpha, IL1, IL6), Th1 (IL12, IFNgamma), and Th2 (IL10) cytokine profiles of immature DC (iDC) from patients with RA and healthy subjects upon triggering of FcgammaR dependent and independent pathways was investigated. iDC, derived from blood monocytes by standardised protocols, were stimulated with immune complexes (IC) at day 6 for 48 hours and, subsequently, for 2 days with LPS in the presence or absence of IC or IFNgamma, resulting in fully matured DC (mDC). IL1, IL6, TNFalpha, IFNgamma, IL12, and IL10 levels in supernatants were measured by ELISA and RIA. RESULTS: mDC from patients with RA showed a markedly increased production of IL1, IL6, TNFalpha, and IL10 compared with DC from healthy donors. Triggering of FcgammaR decreased the production of proinflammatory cytokines IL1, IL12, and IFNgamma by iDC and mDC in RA and controls. The production of IL6 and TNFalpha decreased in patients with RA, whereas it was increased in controls. Triggering of FcgammaR independent mechanisms using IFNgamma increased the production of proinflammatory and Th1 cytokines, which was more pronounced in RA. CONCLUSION: FcgammaR dependent pathways influence cytokine production by DC. A skewed balance towards proinflammatory and Th1 cytokines in RA can, at least partly, be restored by triggering FcgammaR on DC in RA. Insight into the mechanism which determines the FcgammaR balance might lead to new strategies to abrogate Th1 driven inflammatory processes in RA.

Arthritis, Rheumatoid↗
PubMed2004

Increased FcgammaRII expression and aberrant tumour necrosis factor alpha production by mature dendritic cells from patients with active rheumatoid arthritis.

OBJECTIVES: To investigate potential differences in phenotype and behaviour of immature (iDC) and mature dendritic cells (mDC) from patients with RA and healthy subjects. METHODS: iDC and mDC were derived from blood monocytes of patients with RA and healthy controls following standardised protocols. FACS was used to analyse expression of FcgammaRI, II, and III and molecules to characterise DC. Discrimination between FcgammaRIIa and FcgammaRIIb was achieved by RT-PCR. Immunohistochemistry was performed on synovial biopsy specimens of three patients with RA and three healthy controls. TNFalpha production by iDC and mDC upon FcgammaR dependent stimulation was compared between patients with RA and controls by ELISA. RESULTS: iDC from patients with active RA but not from patients with inactive RA or healthy controls markedly up regulated FcgammaRII. mDC from patients with active RA also lacked the physiological down regulation of FcgammaRII that occurs upon maturation in both control groups. RT-PCR analysis confirmed the increased expression of FcgammaRII in RA-especially marked for FcgammaRIIb. FcgammaR dependent stimulation of DC using antigen-IgG immune complexes (IC) significantly increased TNFalpha production by DC from healthy subjects, but significantly decreased TNFalpha by DC from patients with RA. Overlapping expression patterns between FcgammaRII and DC-LAMP in the synovial tissue of patients with RA imply that in vivo, also, mature DC express increased levels of FcgammaRIIb. CONCLUSION: The presence and altered characteristics of DC during active RA suggest that DC help to modulate autoimmunity in RA. Further studies should elucidate the role of local factors in altering the function of DC in RA and in increasing expression of FcgammaRII.

Antigen-Antibody Complex↗
PubMed2003

[Familial hyperactivity of angiotensin-converting enzyme (ACE)].

An extremely high level of serum angiotensin-converting enzyme (ACE) activity was found in eight individuals, women aged 31, 60, 42 and 67 years, and men aged 50, 47, 23 and 50 years. They had consulted a specialist due to a wide range of non-specific complaints or abnormalities (fatigue, dyspnoea, arthralgia, kidney stones with high urinary calcium, neurological symptoms and an elevated blood alkaline phosphatase activity level). As each of these complaints could be a symptom of sarcoidosis, the ACE activity was measured. However, sarcoidosis was not diagnosed in any of these patients. A subsequent analysis revealed that all eight individuals had family members with a similar elevation of ACE. Therefore, the increase in ACE activity was familial. Patients with this disorder have serum ACE levels of between 3 and 7 times the upper limit of normal, whereas in the case of sarcoidosis, serum ACE levels rarely exceed three times this limit. Familial ACE hyperactivity is not accompanied by clinical symptoms. It is caused by a point mutation in the ACE gene, which results in the cell-bound ACE being more readily loosened from the cell surface into the circulatory system.

Adult↗
PubMed2001

Point mutation in the stalk of angiotensin-converting enzyme causes a dramatic increase in serum angiotensin-converting enzyme but no cardiovascular disease.

BACKGROUND: Angiotensin-converting enzyme (ACE) metabolizes many small peptides and plays a key role in blood pressure regulation. Elevated serum ACE is claimed to be associated with an increased risk for cardiovascular disease. Previously, two families with dramatically increased serum ACE were described, but no systematic survey of affected individuals was performed, and the molecular background of this trait is unknown. METHODS AND RESULTS: Eight families were identified with autosomal dominant inheritance of a dramatic (5-fold) increase of serum ACE activity. Strikingly, no clinical abnormalities were apparent in the affected subjects. Isolated blood cells were used for genetic and biochemical analysis. The level of ACE expression on the blood leukocytes and dendritic cells and total cell-associated ACE of the affected individuals was similar to that in nonaffected relatives; however membrane-bound mutant ACE was much more efficiently clipped from the cell surface compared with its wild-type counterpart. A point mutation causing Pro1199Leu in the stalk region of the ACE molecule cosegregates with the increase in serum ACE (LOD score, 6.63). CONCLUSIONS: A point mutation in the stalk region of the ACE protein causes increased shedding, leading to increased serum ACE, whereas cell-bound ACE is unaltered, and affected individuals exhibit no clinical abnormalities. These findings qualify the importance of serum ACE and establish a new determinant of ACE solubilization.

Adult↗
PubMed2001

The dendritic cell-specific CC-chemokine DC-CK1 is expressed by germinal center dendritic cells and attracts CD38-negative mantle zone B lymphocytes.

DC-CK1 (CCL18) is a dendritic cell (DC)-specific chemokine expressed in both T and B cell areas of secondary lymphoid organs that preferentially attracts CD45RA(+) T cells. In this study, we further explored the nature of DC-CK1 expressing cells in germinal centers (GCs) of secondary lymphoid organs using a newly developed anti-DC-CK1 mAb. Immunohistochemical analysis demonstrated a remarkable difference in the number of DC-CK1 expressing cells in adjacent GCs within one tonsil, implicating that the expression of DC-CK1 in GCs depends on the activation and/or progression stage of the GC reaction. Using immunohistology and RNA analysis, we demonstrated that GCDC are the source of DC-CK1 production in the GCs. Considering the recently described function of GCDC in (naive) B cell proliferation, isotype switching and Ab production, we investigated the ability of DC-CK1 to attract B lymphocytes. Here we demonstrate that DC-CK1 is a pertussis toxin-dependent chemoattractant for B lymphocytes with a preference in attracting mantle zone (CD38(-)) B cells. The findings that GCDC produce DC-CK1 and attract mantle zone B cells support a key role for GCDC in the development of GCs and memory B cell formation.

ADP-ribosyl Cyclase↗
PubMed2001

BLC (CXCL13) is expressed by different dendritic cell subsets in vitro and in vivo.

Dendritic cells (DC) attract both T and B lymphocytes to induce an efficient antigen-specific immune response. Recently, it was shown that naïve T cells are attracted to DC by dendritic cell chemokine 1 (DC-CK1, CCL18). The potent B lymphocyte chemoattractant BLC (CXCL13) was previously shown to be essential for homing of lymphocytes into secondary lymphoid organs and for the development of B cell follicles. As the cells that produce BLC are largely unknown and BLC could be a candidate chemokine for the recruitment of B cells to DC, we analyzed different DC subsets for expression of BLC. Here we demonstrate that monocyte-derived DC as well as activated blood DC indeed express and secrete BLC. Interestingly, ligation of the CD40 molecule down-regulated BLC expression in monocyte-derived DC. Staining of tonsilar sections indicated that BLC is expressed by follicular dendritic cells and germinal center dendritic cells (GCDC) in vivo. Real-time quantitative PCR confirmed the expression of BLC in isolated GCDC. Since both B cells and activated T cells express the receptor for BLC, our findings implicate an important role for BLC in establishing the interaction of DC with T cells and B cells. Furthermore, CD40/CD40 ligand interactions could modulate this process by down-regulating the expression of BLC.

CD40 Antigens↗
PubMed2001

Quantitative analysis of chemokine expression by dendritic cell subsets in vitro and in vivo.

Upon maturation, dendritic cells (DCs) have to adjust their chemokine expression to sequentially attract different leukocyte subsets. We used real-time quantitative polymerase chain reaction analysis to study in detail the expression of 12 chemokines involved in the recruitment of leukocytes into and inside secondary lymphoid organs, by DCs in distinct differentiation stages, both in vitro and in vivo. Monocyte-derived immature DCs expressed high levels of DC chemokine 1 (DC-CK1), EBI1-ligand chemokine (ELC), macrophage-derived chemokine (MDC), macrophage-inflammatory protein (MIP)-1alpha, and thymus and activation-regulated chemokine (TARC). Upon maturation, DCs up-regulated the expression of DC-CK1 (60-fold), ELC (7-fold), and TARC (10-fold). Activation of DCs by CD40 ligand further up-regulated the expression of ELC (25-fold). We found that freshly isolated blood DCs expressed only low levels of interleukin-8, lymphotactin, and MIP-1alpha. It is interesting that the chemokine profile expressed by activated CD11c(-) lymphoid-like as well as CD11c(+) myeloid blood DCs mimics that of monocyte-derived DCS: Additionally, purified Langerhans cells that had migrated out of the epidermis expressed a similar chemokine pattern. These data indicate that different DC subsets in vitro and in vivo can express the same chemokines to attract leukocytes.

CD40 Ligand↗
PubMed2000

Dendritic cells break tolerance and induce protective immunity against a melanocyte differentiation antigen in an autologous melanoma model.

Tyrosinase-related protein (TRP) 2 belongs to the melanocyte differentiation antigens and has been implicated as a target for immunotherapy of human as well as murine melanoma. In the current report, we explored the efficacy of nonmutated epitopes with differential binding affinity for MHC class I, derived from mouse TRP2 to induce CTL-mediated, tumor-reactive immunity in vivo within the established B16 melanoma model of C57BL/6 mice. The use of nonmutated TRP2-derived epitopes for vaccination provides a mouse model that closely mimics human melanoma without introduction of xenogeneic or otherwise foreign antigen. The results demonstrate that vaccination with TRP2 peptide-loaded bone marrow-derived dendritic cells (DCs) results in activation of high avidity TRP2-specific CTLs, displaying lytic activity against both B16 melanoma cells and normal melanocytes in vitro. In vivo, protective antitumor immunity against a lethal s.c. B16 challenge was observed upon DC-based vaccination in this fully autologous tumor model. The level of protective immunity positively correlated with the MHC class I binding capacity of the peptides used for vaccination. In contrast, within this autologous model, vaccination with TRP2 peptide in Freund's adjuvant or TRP2-encoding plasmid DNA did not result in protective immunity against B16. Strikingly, despite the observed CTL-mediated melanocyte destruction in vitro, melanocyte destruction in vivo was sporadic and primarily restricted to minor depigmentation of the vaccination site. These results emphasize the potency of DC-based vaccines to induce immunity against autologous tumor-associated antigen and indicate that CTL-mediated antitumor immunity can proceed without development of adverse autoimmunity against normal tissue.

Amino Acid Sequence↗
PubMed2000

Molecular cloning and immunogenicity of renal cell carcinoma-associated antigen G250.

The molecular cloning of the cDNA and gene encoding the renal cell carcinoma (RCC)-associated protein G250 is described. This protein is one of the best markers for clear cell RCC: all clear-cell RCC express this protein, whereas no expression can be detected in normal kidney and most other normal tissue. Antibody studies have indicated that this molecule might serve as a therapeutic target. In view of the induction/up-regulation of G250 antigen in RCC, its restricted tissue expression and its possible role in therapy, we set out to molecularly define the G250 antigen, which we identified as a transmembrane protein identical to the tumor-associated antigen MN/CAIX. We determined, by FISH analysis, that the G250/MN/CAIX gene is located on chromosome 9p12-13. In view of the relative immunogenicity of RCC, we investigated whether the G250 antigen can be recognized by TIL derived from RCC patients. The initial characterization of 18 different TIL cultures suggests that anti-G250 reactivity is rare.

Antigens, Neoplasm↗
PubMed2000

Heterogeneous expression of the SSX cancer/testis antigens in human melanoma lesions and cell lines.

The SSX genes, located on the X chromosome, encode a family of highly homologous nuclear proteins. The SSX1 and SSX2 genes were initially identified as fusion partners of the SYT gene in t(X;18)-positive synovial sarcomas. Recently, however, it was found that these two genes, as well as the highly homologous SSX4 and SSX5 genes, are aberrantly expressed in different types of cancers, including melanomas. Because normal SSX expression has been detected only in the testis and, at very low levels, the thyroid, these proteins are considered as new members of the still growing family of cancer/testis antigens. These antigens are presently considered as targets for the development of cancer immunotherapy protocols. In the present study, we developed a monoclonal antibody found to recognize SSX2, SSX3, and SSX4 proteins expressed in formaldehyde-fixed and paraffin-embedded tissues. This antibody was used to investigate SSX expression in normal testis and thyroid, benign melanocytic lesions, melanoma lesions, and melanoma cell lines. SSX nuclear expression in the testis was found to be restricted to spermatogenic cells, mainly spermatogonia. Of 18 melanoma cell lines analyzed, 9 showed SSX RNA and protein expression, although heterogeneously and at variable levels. Treatment of an SSX-negative cell line with 5-aza-2'-deoxycytidine, a demethylating agent, led to SSX RNA and protein expression, indicating a role for methylation in transcription regulation. Thirty-four of 101 primary and metastatic melanoma cases and 2 of 24 common nevocellular and atypical nevus cases showed SSX nuclear staining. Again, SSX expression was heterogeneous, ranging from widespread to scarce. Our findings stress the importance of assessing the a priori SSX expression status of melanoma cases that may be selected for immunotherapeutic trials.

Adult↗
PubMed2000

Identification of DC-SIGN, a novel dendritic cell-specific ICAM-3 receptor that supports primary immune responses.

Contact between dendritic cells (DC) and resting T cells is essential to initiate a primary immune response. Here, we demonstrate that ICAM-3 expressed by resting T cells is important in this first contact with DC. We discovered that instead of the common ICAM-3 receptors LFA-1 and alphaDbeta2, a novel DC-specific C-type lectin, DC-SIGN, binds ICAM-3 with high affinity. DC-SIGN, which is abundantly expressed by DC both in vitro and in vivo, mediates transient adhesion with T cells. Since antibodies against DC-SIGN inhibit DC-induced proliferation of resting T cells, our findings predict that DC-SIGN enables T cell receptor engagement by stabilization of the DC-T cell contact zone.

Animals↗
PubMed2000

DC-STAMP, a novel multimembrane-spanning molecule preferentially expressed by dendritic cells.

Dendritic cells (DC) are unique in their ability to present antigen to naive T cells, and therefore play a central role in the initiation of immune responses. Characterization of DC-specific genes may help to unravel the mechanism underlying their potent antigen presenting capacity. Here we describe the identification of a novel transcript, isolated by random sequencing of a cDNA library prepared from monocyte-derived DC, which we termed DC-specific transmembrane protein (DC-STAMP). DC-STAMP is specifically expressed by DC, and not in a panel of other leukocytes or non-hematopoietic cells. Interestingly, DC-STAMP was also detected in activated but not resting blood DC. The DC-STAMP transcript encodes a 470-amino acid protein containing seven putative transmembrane domains. Expression of a DC-STAMP-GFP fusion protein in 293 cells indicates that DC-STAMP is expressed at the cell surface, and has an intracellular C terminus. Surprisingly, no sequence homology was found with any other protein or multimembrane-spanning receptor. Therefore, we propose that DC-STAMP is a novel DC-specific multimembrane-spanning protein, representing a new group of transmembrane proteins.

Amino Acid Sequence↗