IL-13 induces CD34+ cells isolated from G-CSF mobilized blood to differentiate in vitro into potent antigen presenting cells

Periodontal Inflamed Surface Area (PISA) associates with composites of salivary cytokines

BACKGROUND

Periodontal disease (PerioD) is a chronic, complex inflammatory condition resulting from the interaction between subgingival dysbiotic bacteria and the host immune response leading to local inflammation. Since periodontal inflammation is characterized by multiple cytokines effects we investigated whether Periodontal Inflamed Surface Area (PISA), a continuous measure of clinical periodontal inflammation is a predictor of composite indexes of salivary cytokines.

METHODS AND FINDINGS

In a cross-sectional study of 67 healthy, well-educated individuals, we evaluated PISA and several cytokines expressed in whole stimulated saliva. Two salivary cytokine indexes were constructed using weighted and unweighted approaches based on a Principal Component Analysis [named Cytokine Component Index (CCI)] or averaging the (standardized) level of all cytokines [named Composite Inflammatory Index (CII)]. In regression analysis we found that PISA scores were significantly associated with both salivary cytokine constructs, (CCI: part R = 0.51, p<0.001; CII: part R = 0.40, p = 0.001) independent of age, gender and BMI showing that single scores summarizing salivary cytokines correlated with severity of clinical periodontal inflammation.

CONCLUSIONS

Clinical periodontal inflammation may be reflected by a single score encompassing several salivary cytokines. These results are consistent with the complexity of interactions characterizing periodontal disease. In addition, Type I error is likely to be avoided.

Modulation of Cytokines Production by Indomethacin Acute Dose during the Evolution of Ehrlich Ascites Tumor in Mice

The aim of the present study was to investigate the influence of a nonselective COX1/COX2 inhibitor (indomethacin) on tumor growth of Ehrlich Ascites Tumor (EAT) in mice, using as parameters the tumor growth and cytokine profile. Mice were inoculated with EAT cells and treated with indomethacin. After 1, 3, 6, 10, and 13 days the animals were evaluated for the secretion of TNFα, IL-1α, IL-2, IL-4, IL-6, IL-10, and IL-13 and PGE2 level in peritoneal cavity. The results have shown that EAT induces PGE2 production and increases tumor cells number from the 10th day. The cytokine profile showed EAT induces production of IL-6 from 10th day and of IL-2 on 13th day; the other studied cytokines were not affected in a significant way. The indomethacin treatment of EAT-bearing mice inhibited the tumor growth and PGE2 synthesis from the 10th day. In addition, the treatment of EAT-bearing mice with indomethacin has stimulated the IL-13 production and has significantly inhibited IL-6 in the 13th day of tumor growth. Taken together, the results have demonstrated that EAT growth is modulated by PGE2 and the inhibition of the tumor growth could be partly related to suppression of IL-6 and induction of IL-13.

Current approaches in dendritic cell generation and future implications for cancer immunotherapy

The discovery of tumor-associated antigens, which are either selectively or preferentially expressed by tumors, together with an improved insight in dendritic cell biology illustrating their key function in the immune system, have provided a rationale to initiate dendritic cell-based cancer immunotherapy trials. Nevertheless, dendritic cell vaccination is in an early stage, as methods for preparing tumor antigen presenting dendritic cells and improving their immunostimulatory function are continuously being optimized. In addition, recent improvements in immunomonitoring have emphasized the need for careful design of this part of the trials. Still, valuable proofs-of-principle have been obtained, which favor the use of dendritic cells in subsequent, more standardized clinical trials. Here, we review the recent developments in clinical DC generation, antigen loading methods and immunomonitoring approaches for DC-based trials.

IL-13 replaces IL-4 in development of monocyte derived dendritic cells (MoDC) of swine

Dendritic cells (DCs) are a critical aspect of innate immune responses in addition to initiating adaptive immunity. In vitro generation of monocyte derived dendritic cells (MoDC) by culturing cells in IL-4 and granulocyte/macrophage colony stimulating factor (GM-CSF) has been reported for multiple species including swine. However, IL-4 is not a prominent cytokine detected in the periphery of common breeds of swine such as Yorkshire pigs. In this study, we report the generation and characterization of porcine MoDC in vitro using porcine IL-13 and porcine GM-CSF. These cells have the predicted expression of Class II MHC and T cell costimulatory molecules, phagocytic capacity and the ability to process and present antigen. Critically, porcine IL-13/GM-CSF MoDC have the unique ability to stimulate a primary mixed lymphocyte response in vitro. The type I interferon response of these MoDC to poly I:C (TLR3 ligand), LPS (TLR4 ligand) and CpG (TLR9 ligand) was tested. Of these TLR agonists, LPS or CpG did not stimulate induction of type I interferons, but a strong response was observed to poly I:C. This analysis shows that the generation of MoDCs in IL-13 yields cells of equivalent phenotype and function as IL-4 generated DC. However, for swine, in vitro generation of MoDC in IL-13 is likely to induce a more physiological cell population to study given expression of IL-4 is lacking in the periphery of these animals.

Dendritic cell-derived IL-2 production is regulated by IL-15 in humans and in mice

Dendritic cells (DCs) are involved in the initiation and regulation of innate and adaptive immune responses. Several molecular mechanisms regulate these diverse DC functions, and we have previously reported that mouse dendritic cells (mDCs) can produce interleukin-2 (IL-2) in vitro and in vivo, in response to microbial activation and T-cell-mediated stimuli. This property is shared by different DC subtypes, including Langerhans cells. Here we show that, on appropriate stimulation, human DCs, both plasmacytoid and myeloid subtypes, also express IL-2. Interestingly, the production of IL-2 by myeloid DCs is induced by T-cell-mediated stimuli and depends on the presence of IL-15. The key role of this cytokine in regulating IL-2 production was also confirmed in the mouse system. In particular, we could show that DCs from IL-15-deficient mice were strongly impaired in the ability to produce IL-2 after interactions with different microbial stimuli. Our results indicate that DC-produced IL-2 is tightly coregulated with the expression of IL-15.

Dendritic cells: friend or foe in autoimmunity?

The large amount of information that has been acquired from human and animal models substantiates that the DC lineage system represents a double-edged sword in the immune system. Presumably, in normal physiology, tolerizing DCs guard against autoimmunity and control established immune reactions, whereas immunogenic DCs provide active host defenses. In autoimmune diseases, there is strong evidence to support the idea that tolerance is overridden by the development of immunogenic DCs that favor cross-priming. Based on the wide range of possible clinical applications, it is not surprising that manipulation of DCs for clinical benefit is rampant. Indeed, multiple clinical strategies are currently underway, including the development of DC immunotherapy for cancer vaccines and graft survival. In cancer, DC-based vaccines for solid tumors, such as melanoma, were well-tolerated and produced beneficial antitumor responses, even in patients who had advanced disease. Although initial trials such as these are highly promising, the ultimate goal is to develop DC-based strategies that will lead to highly specific, long-lasting immunity against the cancer cells. In autoimmune diseases and transplant settings, the goal is to devise strategies that will block the initiation and maintenance of autoreactive and antigraft responses, respectively. Specific strategies for autoimmune diseases might include interference with cross-priming events that activate autoreactive T cells and genetic engineering to introduce molecules that have immunosuppressive functions, such as IL-10, TGF3, Fas ligand, ILT3, and ILT4. Successful application to these diseases will necessitate high specificity. In this regard, recent preliminary studies that described antigen-specific suppression of a primed immune response by tolerogenic DCs are especially informative.

Comparison of monocyte enrichment by immuno-magnetic depletion or adherence for the clinical-scale generation of DC

BACKGROUND

DC generated from monocytes have been used for vaccines. We have developed a monocyte enrichment procedure by depleting T and B cells with anti-CD2 and anti-CD19 Abs using the automated Isolex 300i magnetic cell selector for clinical-scale DC generation in gas permeable SteriCell culture bags. We have also compared DC function, yield and purity of DC generated from adherent monocytes using culture bags in a closed system, with DC generated in conventional tissue culture flasks.

METHODS

Monocytes were enriched from normal donor apheresis products using CD2/19 depletion with experimental software on the Isolex 300i (ISO), adherence (AD) to SteriCell bags and to T175 flasks and then cultured for 7 days in serum-free X-VIVO 15 media with GM-CSF and IL-4. Phenotype and dextran uptake were analyzed by flow cytometry and allogeneic MLR was also evaluated.

RESULTS

ISO-DC and AD-DC from SteriCell bags showed similar viability. Higher purity of ISO-DC than AD-DC was measured by forward- and side-scatter flow cytometry. Similar expression of CD1a, CD80, CD86 and CD83 were observed in both ISO-DC and AD-DC. Similar dextran uptake and allo MLR were also observed.

DISCUSSION

These data indicated that functional DC were generated in gas permeable SteriCell culture bags from both ISO- and AD-monocytes in a closed system.

The clinical implications of mixed lymphocyte reaction with leukemic cells

To evaluate the clinical implications of a mixed lymphocyte reaction between leukemic cells and lymphocytes from HLA-matched sibling donors, we attempted to generate donor-derived, graft-versus-leukemia-effective cells and to define their characteristics. We studied 8 patients with chronic myelogenous leukemia (CML), including 5 patients in the chronic phase (CP), 3 patients in the accelerated phase (AP), and 2 patients with acute myelogenous leukemia (AML) in their first complete remission. Cells from these patients were used as stimulators in a mixed lymphocyte reaction.The effects of natural killer (NK) cells and cytotoxic T-lymphocytes (CTLs) were separated by observing tests for cytotoxicity to target cells, including K562 cells, the patient's leukemic cells, and phytohemagglutinin (PHA) blasts. Donor-derived antileukemic CTLs againstthe patient's own leukemic cells are productive in vitro. The efficacy of generating CTLs against leukemic target cells was (in decreasing order) AML, CML-CP, and CML-AP. Cytotoxic activity against leukemic targets was prominent in 4 cases--2 CML-CP and the 2 AML cases. On the contrary, the 3 cases of CML-AP showed low CTL activity. In cases showing 1 positive result among 3 targets (K562 cells, the patient's leukemic cells, and PHA blasts), the relapse rate was significantly lower (P = .022) on follow-up (median, 33 months; 7-40 months) after hematopoietic stem cell transplantation. By a combined analysis of the cytotoxicity effects for all 3 target cells, we were able to demonstrate a correlation between leukemic relapse and the variable degree of the cytotoxicity test results. Although the total sample numbers for this study were low, we speculate that these results may come from differences in the individual characteristics of the leukemic cells that are in line with their clinical disease status.

Development of a closed-system process for clinical-scale generation of DCs: evaluation of two monocyte-enrichment methods and two culture containers

BACKGROUND

Clinical immunotherapy trials using DCs depend on large-scale methods for DC generation that fulfil current good manufacturing practice requirements. Our goal was to develop data on two variables, monocyte-enrichment method and culture container, which could be used to design a closed-system process for ex vivo generation of immature DCs.

METHODS

Mononuclear cells were collected by leukapheresis and enriched for monocytes by either counterflow centrifugal elutriation, or immunomagnetic selection using Isolex, an automated closed-system device. Monocytes were cultured for 7 days in serum-free medium with GM-CSF and IL-4, using either plastic flasks or gas-permeable Stericell bags. Monocytes and cultured DCs were evaluated for yield, flow cytometric phenotype, and in vitro function in MLR, and autologous recall responses to tetanus toxoid and influenza virus.

RESULTS

Enriched monocyte products from elutriation and immunomagnetic selection were equivalent in yield and purity, and were capable of generating immature DCs in either flasks or bags. DCs from all four culture conditions were equivalent in yield, phenotype, and in vitro function. Mean DC yield was 67-80% per seeding monocyte, and 11-13% per starting mononuclear cell (MNC). A leukapheresis product containing 5 x 10(9) MNCs processed by this method could therefore yield approximately 5 x 10(8) immature DCs.

DISCUSSION

In this manufacturing process, the Isolex system was equivalent to elutriation, and Stericell bags were equivalent to flasks. Together, the Isolex system and Stericell bags can be incorporated into a closed-system process to generate immature DCs.

Generation of large numbers of dendritic cells in a closed system using Cell Factories

There is a growing interest in using dendritic cells (DC) for vaccine approaches in the treatment of cancer and infectious diseases. This requires a reproducible method for the generation of large numbers of DC in a closed culture system suitable for clinical use and conforming to the current guidelines of good manufacturing practices. We designed a system in which the DC were generated in a closed system from adherent monocytes using Cell Factories (DC-CF). Monocytes were enriched from apheresis products by adherence and then cultured in the presence of AB serum or autologous plasma and GM-CSF and IL-4 for 6 days. The DC generated in Cell Factories were extensively compared to research-grade DC generated in conventional tissue culture flasks (DC-TCF). At day 6, the immature DC were harvested and the yield, the viability, the immunophenotype and the functional characteristics of the DC were compared.DC-CF and DC-TCF showed similar viability and purity and scored equally when tested for stability, dextran and latex bead uptake, in MLR and in the activation of influenza-specific memory cells after electroporation with influenza matrix protein 1 (IMP1) mRNA. These data indicated that large numbers of functional clinical-grade DC could be generated from adherent cells in a closed system using Cell Factories.

In vitro production of dendritic cells from human blood monocytes for therapeutic use

Dendritic cells (DC) are professional antigen-presenting cells that are promising adjuvants for clinical immunotherapy. Methods to generate in vitro large numbers of functional human DC using either peripheral blood monocytes or CD34(+) pluripotent hematopoietic progenitor cells have been now developed. For this purpose, their in vitro production for further clinical use need to fit good manufacturing practice (GMP) conditions. In the present review, we give our experience of such a procedure: it includes collection of mononuclear cells by apheresis, separation of monocytes by elutriation, and culture of monocytes with GM-CSF + IL-13 + human serum (autologous patient's serum or AB serum) or in a serum-free medium (AIM V). The characteristics of monocyte-derived DC grown in these various conditions varied mainly regarding their phenotype and their morphology in confocal microscopy, whereas no significant differences were found in their capacity to phagocytize latex particles and to stimulate allogeneic (MLR) or autologous lymphocytes (antigen-presentation tests). The DC were also cryopreserved in bags (either by putting the bags directly in a -80 degrees C mechanical freezer or using a classical liquid nitrogen controlled-rate freezer at -1 degrees C/min) in a solution containing 10% dimethyl sulfoxide (Me(2)SO) and 2% human albumin in doses of DC available for several infusions. The mean recoveries after freezing and thawing were not statistically different (around 70%). The immunophenotype of DC, as well as the T lymphocyte-stimulating capacity, were not modified by the freezing--thawing procedure. The results obtained demonstrate that the experimental conditions we set up are easily applicable in clinical trials and lead to large numbers of well-defined DC. Clinical trials using DC already published will be discussed.

Dendritic cells (DCs) in rheumatoid arthritis (RA): progenitor cells and soluble factors contained in RA synovial fluid yield a subset of myeloid DCs that preferentially activate Th1 inflammatory-type responses

There is evidence that mature dendritic cells (DCs) present in the rheumatoid arthritis (RA) joint mediate immunopathology in RA. In this study, we indicate that early myeloid progenitors for DCs and DC growth factors existing in RA synovial fluid (SF) are also likely participants in the RA disease process. A fraction of cells lacking markers associated with mature DCs or DC precursors and enriched in CD34(negative) myeloid progenitors was isolated from RA SF. These cells proliferated extensively when cultured in vitro with cytokines that promote the growth of myeloid DCs (GM-CSF/TNF/stem cell factor/IL-4) and, to a lesser degree, when cultured with monocyte/granulocyte-restricted growth factors (M-CSF/GM-CSF). Mature DCs derived from RA SF progenitors with CD14-DC cytokines known to be prevalent in the inflamed RA joint (GM-CSF/TNF/stem cell factor/IL-13) were potent stimulators of allogeneic T cells and inflammatory-type Th1 responses and included CD14-DC subtypes. Cell-free RA SF facilitated DC maturation from myeloid progenitors, providing direct evidence that the inflamed RA joint environment instructs DC growth. Enhanced development of CD14-derived DCs was correlated with the presence of soluble TNFR (p55), raising the possibility that soluble TNFR also regulate CD14-derived DC growth in vivo. SF from patients with osteoarthritis contained neither myeloid DC progenitors nor DC growth factors. The existence of DC progenitors and myeloid DC growth factors in RA SF supports the concept that RA SF may be a reservoir for joint-associated DCs and reveals a compelling mechanism for the amplification and perpetuation of DC-driven responses in the RA joint, including inflammatory-type Th1 responses.

Immunologic profiles of effector cells and peripheral blood stem cells mobilized with different hematopoietic growth factors

BACKGROUND

Peripheral blood stem cells (PBSC) have become the preferred source of stem cells for autologous transplantation because of the technical advantage and the shorter time to engraftment. Mobilization of CD34(+) cells into the peripheral blood can be achieved by the administration of G-CSF or GM-CSF, or both, alone or in combination with chemotherapy. G-CSF and GM-CSF differ somewhat in the number and composition of CD34(+) cells and effector cells mobilized to the peripheral blood. However, the molecular mechanism underlying the release and engraftment of CD34(+) cells is poorly understood.

PURPOSE

The purpose of this review is to give a recent update on the type and immunological properties of effector cells and CD34(+) cells mobilized by the different growth factors with emphasis on A) mobilization of T cells, natural killer cells, and dendritic cells; B) coexpression of adhesion molecules such as VLA-4 and L-selectin in mobilized PBSC collection, and C) coexpression of CXCR4-the receptor for the stromal-derived differentiation factor 1-with latest information shedding light on the molecular mechanism underlying the release and subsequent engraftment of CD34(+) cells.

CONCLUSIONS

A) The reported suppression of T cell and NK cell functions in PBSC apheresis collections in patients primed with G-CSF or GM-CSF is controversial and may merely reflect low effector cell activity before mobilization. B) A decrease in the expression of adhesion molecules such as VLA-4 and L-selectin is a necessary requirement for the release of CD34(+) cells to the peripheral blood. C) A decrease in the expression of CXCR4 is a necessary requirement for the release of CD34(+) cells to the peripheral blood and correlates with mobilization success.

Simplified method to generate large quantities of dendritic cells suitable for clinical applications

The present study describes the optimization of an in vitro culture method for generating large amounts of dendritic cells (DC) in serum-free conditions from leukapheresis containing a mixed population of peripheral blood mononuclear cells (PBMC) which are cultured in the presence of GM-CSF and IL-13. Initial comparisons between the generation of DC from bulk and monocyte-enriched leukapheresis products showed that the presence of lymphocytes during the culture favors the differentiation of monocytes into DC. DC yields obtained from mixed mononuclear cell cultures were between 38 and 54% higher than yields obtained from monocyte-enriched cultures. Both types of cultures resulted in the generation of DC with an immature phenotype (CD83- and high phagocytic activity), which have been previously shown to be good stimulators for T cell responses. DC yields of bulk cultures in serum-free conditions were significantly higher than those obtained in the presence of 2% human serum. The cytokines of the supernatants of serum-free cultures comprised a significant content of pro-inflammatory cytokines such as IL-1, IL-12 and TNF-alpha. Maturation of DC generated by this method can be induced by treatment with double-stranded RNA, LPS or TNF-alpha, resulting in enhanced surface expression of CD80, CD86, CD40, CD83 and MHC molecules on the DC. The methodology described here offers the possibility for generating large amounts of clinical grade DC from bulk leukapheresis products, thus avoiding DC precursor purification steps, and thereby minimizing the risks of contamination. This culture process may be applied to cell-based therapeutic approaches for the treatment of cancer or chronic viral infections.

Adenoviral transduction of human 'clinical grade' immature dendritic cells enhances costimulatory molecule expression and T-cell stimulatory capacity

The therapeutic use of dendritic cells (DC) in antigen-specific anti-tumor vaccines, requires sufficient numbers of functional DC, the preparation of which should comply with the code of Good Manufacturing Practice. In addition, the expression of tumor specific antigen should be possible in these DC. As a preclinical step, the method reported here was developed in healthy volunteers. Monocytes (Mo) were isolated by leukapheresis from 12 donors, purified by elutriation and then cultured for 6 days in sealed bags in AIM-V serum free medium with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-13 (IL-13). Between 6x10(8) and 1x10(9) immature DC (iDC) could be differentiated from one leukapheresis. Cells displayed a characteristic iDC phenotype (CD1a(+), CD14(-), CD80(+), CD86(+), HLA DR(+), CD83(-)), and had potent allogeneic and antigen dependent autologous T cell-stimulatory capacity. Moreover, iDC could be further differentiated into mature DC by CD40 ligation as assessed by CD83 expression and the upregulation of HLA-DR and costimulatory molecules. After infection with a recombinant adenovirus encoding for beta-galactosidase (betaGal), 50% to 80% of iDC expressed betaGal without toxicity. Adenovirus infection increased the expression of both costimulatory molecules and CD83, and also increased allogeneic stimulatory capacity. Thus, the method developed here allows us to use large numbers of functional iDC as will be required for therapeutic uses in man. These DC can express a transgenic protein.

In vitro generation of dendritic cells from human blood monocytes in experimental conditions compatible for in vivo cell therapy

DC are professional APC that are promising adjuvants for clinical immunotherapy. Methods to generate in vitro large numbers of functional human DC using either peripheral blood monocytes or CD34+ pluripotent HPC have been developed recently. However, the various steps of their in vitro production for further clinical use need to fit good manufacturing practice (GMP) conditions. Our study focused on setting up such a full procedure, including collection of mononuclear cells (MNC) by apheresis, separation of monocytes by elutriation, and culture of monocytes with GM-CSF + IL-13 + autologous serum (SAuto) in sterile Teflon bags. The procedure was first developed with apheresis products from 7 healthy donors. Its clinical feasibility was then tested on 7 patients with breast cancer. The characteristics of monocyte-derived DC grown with SAuto (or in some instances with a pooled AB serum) were compared with those obtained in the presence of FBS by evaluation of their phenotype, their morphology in confocal microscopy, and their capacity to phagocytize latex particles and to stimulate allogeneic (MLR) or autologous lymphocytes (antigen-presentation tests). The results obtained demonstrate that the experimental conditions we set up are easily applicable in clinical trials and lead to large numbers of well-defined SAuto-derived DC as efficient as those derived with FBS.

Dendritic cell biology and the application of dendritic cells to immunotherapy of multiple myeloma

Dendritic cells (DCs) are extremely efficient antigen-presenting cells that are potent stimulators of both B and T cell immune responses. Although DCs are normally present in extremely small numbers in the circulation, recent advances in DC biology have made it possible to generate DCs in culture. DCs can be generated in vitro from various cellular sources including bone marrow, cord blood and peripheral blood. Although culture conditions are extremely diverse, the majority of protocols grow DCs in GM-CSF and either TNF-alpha and/or IL-4. The addition of other growth factors such as SCF and Flt-3 ligand can dramatically enhance DC recovery. It is important to appreciate that DC subsets have been identified. Thus, DC at different stages of maturation, based on phenotype and capacity to capture antigen, can be obtained depending on culture conditions. For clinical applications, DCs can be generated in serum-free media and cryopreserved for future clinical applications. The ability to obtain DCs in numbers suitable for manipulating immune responses has pushed DC-based immunotherapies into the spotlight for treatment of various malignancies, including multiple myeloma, a B cell malignancy that is presently incurable. Although high-dose chemotherapy and transplantation have improved complete remission rates and overall survival in myeloma, immunotherapeutic strategies are needed for the additional cytoreduction needed to achieve a cure. Because DCs specialize in antigen capture and are extremely potent at stimulating T cell responses, they are ideally suited for generating anti-myeloma T cell responses in vivo. Several studies have demonstrated that myeloma protein, also called idiotype (Id), is sufficiently immunogenic and can be used to generate in vivo T cell responses in myeloma patients. Clinical trials using Id-pulsed DCs as a vaccine to treat minimal residual disease or relapsed myeloma are currently underway. Feasibility studies indicate that antigen-pulsed autologous DCs can be used to elicit in vivo Id-specific T cell responses. Additional studies are needed to optimize current DC vaccination protocols and determine clinical benefits associated with this approach. It is hoped that, following conventional therapies, a combination of adoptive immunotherapeutic modalities such as DCs together with myeloma-specific T cells may lead to improved clinical responses in multiple myeloma, and ultimately lead to complete remission and cure.

Interleukin-13 is involved in functional maturation of human peripheral blood monocyte-derived dendritic cells

Dendritic cells (DCs) are professional antigen presenting cells (APCs) that are required for the initiation of the immune response. DCs have been shown to be generated from hematopoietic stem cells, but relatively little is known about the regulation underlying differentiation and activation of DCs. Here, we report that recombinant human (rh)IL-13 induces functional maturation of rhGM-CSF plus rhIL-4 generated monocyte-derived immature DCs. Incubation of these immature DCs with rhIL-13 or rhTNF-alpha for 2 days resulted in increased surface expression of CD1a, CD11c, CD86 and HLA-DR. The DCs treated with rhIL-13 or rhTNF-alpha, but not rhIL-4, for 2 days were more efficient than unstimulated DCs in the primary autologous/allogeneic T-cell response whereas the antigen (Ag)-specific T-cell response was suppressed. The treatment of DCs with rhIL-13 as well as rhTNF-alpha for 4 days down-modulated endocytic capacity for FITC-dextran (FITC-DX) and lucifer yellow (LY), and induced surface expression of CD83. Morphological, phenotypical, and functional analyses revealed that the monocytes cultured with rhGM-CSF plus rhIL-13 gave rise to a DC type more mature than rhGM-CSF plus rhIL-4-induced DCs. These findings revealed a new role for rhIL-13 in regulating both the maturation and activation of DCs.