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Dolores J Schendel

Publications and source records attributed to Dolores J Schendel.

At least 19 recordsLinked to original sources
PubMed2006

Cytotoxic markers and frequency predict functional capacity of natural killer cells infiltrating renal cell carcinoma.

PURPOSE: Renal cell carcinoma harbors high numbers of infiltrating lymphocytes with apparent limited efficacy in tumor control. This study focused on the natural killer (NK) cells infiltrating renal cell carcinoma. EXPERIMENTAL DESIGN: Tumor-infiltrating lymphocytes (TIL) were isolated from renal cell carcinoma and analyzed for NK cell frequency and phenotype (n = 34). NK cells were enriched and tested for effector function. RESULTS: Two renal cell carcinoma subtypes were identified, one containing high (>20% of the lymphocyte population, n = 14), the other low (<20%, n = 20), NK cell numbers. NK cells of both groups were noncytolytic ex vivo but differed in CD16 and cytotoxic effector molecule expression as well as in their capacity to acquire cytotoxic activity: The majority of NK cells from tumors with high NK cell content (high NK-TIL) were CD16(bright), whereas few CD16bright NK cells were found in tumors with low NK cell frequencies (low NK-TIL). The CD16 dichotomy correlated with different capacities to develop cytotoxicity after short-term activation with interleukin-2 ex vivo: Low NK-TIL remained noncytolytic against K562 and unresponsive to signals via the activating receptor NKp46 despite expression of receptor and adaptor molecules. In contrast, high NK-TIL acquired cytotoxic function. As described for peripheral CD16bright NK cells, NK cells from high-NK tumors showed high per cell expression of granzyme A, granzyme B, and perforin. NK cells from low NK-TIL resembled CD16(neg/dim) peripheral NK cells with few cytotoxin+ cells and lower expression of perforin. CONCLUSION: The extent of NK cell infiltration and the expression of markers (CD16 and cytotoxins) predict the functional capacity of NK cells infiltrating renal cell carcinoma and can be used to characterize subgroups of renal cell carcinoma.

Adult↗
PubMed2006

TCR-independent cytokine stimulation induces non-MHC-restricted T cell activity and is negatively regulated by HLA class I.

Recent evidence suggests that the functional status of T cells activated independently from their TCR differs substantially from classical MHC-restricted T cells. Here, we show that TCR-independent, short-term stimulation via the common gamma-chain of the IL-2/IL-15 receptor induces non-MHC-restricted cytotoxicity and sustained cytokine secretion in purified CD4+ or CD8+ T cells. NK-like cytotoxicity is directed against MHC class I-negative targets and can be inhibited by classical and non-classical HLA class I molecules. Known inhibitory receptors, such as CD85j (ILT2) and leukocyte-associated Ig-like receptor-1, are not responsible for this HLA-mediated inhibition. NK-like cytotoxicity can be costimulated by NKG2D (CD314) triggering, but 2B4 (CD244) and DNAM-1 (CD226) are not involved. NK-like T cells display an activated phenotype and secrete various cytokines, including IFN-gamma, TNF-alpha, IL-5, IL-13 and MIP-1beta. Under normal conditions, HLA class I-mediated inhibition may function as a safety mechanism to prevent unbalanced cytokine production and effector killing mechanisms by T cells that were activated independently from their TCR. Non-MHC-restricted activity represents a functional status rather than a property of distinct T cell subpopulations. Thus, cytokine-induced, non-MHC-restricted T cells may be relevant in immune responses against tumors showing aberrant MHC expression through their capacities of cytokine production and direct tumor cell eradication.

Cytokines↗
PubMed2006

Designer T cells by T cell receptor replacement.

T cell receptor (TCR) gene transfer is a convenient method to produce antigen-specific T cells for adoptive therapy. However, the expression of two TCR in T cells could impair their function or cause unwanted effects by mixed TCR heterodimers. With five different TCR and four different T cells, either mouse or human, we show that some TCR are strong--in terms of cell surface expression--and replace weak TCR on the cell surface, resulting in exchange of antigen specificity. Two strong TCR are co-expressed. A mouse TCR replaces human TCR on human T cells. Even though it is still poorly understood why some TCRalpha/beta combinations are preferentially expressed on T cells, our data suggest that, in the future, designer T cells with exclusive tumor reactivity can be generated by T cell engineering.

Animals↗
PubMed2006

Immunotherapy of lung cancer: an update.

In Germany lung cancer is the leading cause of cancer-associated death in men. Surgery, chemotherapy and radiation may enhance survival of patients suffering from lung cancer but the enhancement is typically transient and mostly absent with advanced disease; eventually more than 90% of lung cancer patients will die of disease. New approaches to the treatment of lung cancer are urgently needed. Immunotherapy may represent one new approach with low toxicity and high specificity but implementation has been a challenge because of the poor antigenic characterization of these tumors and their ability to escape immune responses. Several different immunotherapeutic treatment strategies have been developed. This review examines the current state of development and recent advances with respect to non-specific immune stimulation, cellular immunotherapy (specific and non-specific), therapeutic cancer vaccines and gene therapy for lung cancer. The focus is primarily placed on immunotherapeutic cancer treatments that are already in clinical trial or well progressed in preclinical studies. Although there seems to be a promising future for immunotherapy in lung cancer, presently there is not standard immunotherapy available for clinical routine.

Cancer Vaccines↗
PubMed2006

Coexpression of CD25 and OX40 (CD134) receptors delineates autoreactive T-cells in type 1 diabetes.

T-cell-mediated loss of pancreatic beta-cells is the crucial event in the development of type 1 diabetes. The phenotypic characteristics of disease-associated T-cells in type 1 diabetes have not yet been defined. The negative results from two intervention trials (the Diabetes Prevention Trial-Type 1 Diabetes and the European Nicotinamide Diabetes Intervention Trial) illustrate the need for technologies to specifically monitor ongoing autoimmune reactions. We used fluorescence-activated cell sorter analysis to study surface marker expression on T-cell lines specific for two major type 1 diabetes autoantigens, GAD65 and proinsulin. We then applied this knowledge in a cross-sectional approach to delineate the phenotype of circulating memory T-cells. The autoreactive T-cells of patients could be distinguished from those of control subjects by their coexpression of CD25 and CD134. Autoantigen-specific T-cells that recognized multiple GAD65- and preproinsulin-derived peptides and coexpressed CD25(+)CD134(+) were confined to patients (n = 32) and pre-diabetic probands (n = 5). Autoantigen-reactive T-cells in control subjects (n = 21) were CD25(+)CD134(-) and recognized fewer autoantigen-derived peptides. Insulin therapy did not induce CD25(+)CD134(+) T-cells in type 2 diabetic patients. The coexpression of CD25 and the costimulatory molecule CD134 on memory T-cells provides a novel marker for type 1 diabetes-associated T-cell immunity. The CD134 costimulatory molecule may also provide a novel therapeutic target in type 1 diabetes.

Autoimmunity↗
PubMed2005

Pulmonary T(H)2 response in Pseudomonas aeruginosa-infected patients with cystic fibrosis.

BACKGROUND: Pseudomonas aeruginosa infection determines the course of cystic fibrosis (CF) lung disease. Studies in human peripheral blood indicate that P aeruginosa infection is associated with a predominant T(H)2 immune response, whereas T(H)1 responses are accompanied by a better pulmonary outcome. OBJECTIVE: Analyses of peripheral blood may not correspond directly with the local pulmonary immune response. Therefore, we asked whether the T(H)1/T(H)2 response is altered in bronchoalveolar lavage fluid from P aeruginosa-infected patients with CF. METHODS: Bronchoalveolar lavage fluid was obtained from 12 patients with CF chronically infected with P aeruginosa, 11 noninfected patients with CF, and 8 healthy controls. Pulmonary CXCR3(+) (T(H)1) and CCR4(+) (T(H)2) expressing CD4(+) and CD8(+) lymphocytes were quantified by flow cytometry. Levels of T(H)1-associated (IL-2, IFN-gamma, IFN-gamma inducible T cell-alpha chemoattractant, Monokine induced by IFN-gamma, IFN-gamma inducible protein of 10 kd) and T(H)2-associated (IL-4, IL-5, IL-10, thymus and activation-regulated chemokine [TARC], macrophage-derived chemokine) cytokines and chemokines and a panel of proinflammatory molecules were quantified at the protein level. Chemokines mRNA levels were assessed by real time RT-PCR. RESULTS: P aeruginosa-infected patients with CF had significantly higher levels of pulmonary CCR4(+)CD4(+) (T(H)2) cells, IL-4, IL-13, and TARC and lower levels of IFN-gamma compared with noninfected patients with CF and healthy controls. Bronchoalveolar lavage fluid levels of IL-4, IL-13, and TARC correlated inversely with FEV(1) in P aeruginosa-infected patients with CF. CONCLUSION: These results reveal the prevalence of a pulmonary T(H)2 immune response in P aeruginosa-infected patients with CF. The modulation of the pulmonary T(H)2 response in P aeruginosa infection may be an option for the treatment of P aeruginosa lung disease in patients with CF.

Adolescent↗
PubMed2005

Association between levels of Toll-like receptors 2 and 4 and CD14 mRNA and allergy in pregnant women and their offspring.

The microbial environment in early infancy or even in utero may modulate the risk to develop allergic disease. Since Toll-like receptors (TLR) recognize microbial products, we hypothesized that maternal allergies may be associated with decreased levels of TLR2, TLR4 and CD14 mRNA in mothers and their offspring. 185 healthy pregnant women from Germany (n = 48), Hungary (n = 50) and Spain (n = 87) were enrolled in a European multicenter study. Levels of TLR2, TLR4 and CD14 mRNA were quantified in maternal peripheral blood samples taken at delivery and placental cord blood samples. Numbers of TLR2+, TLR4+ and CD14+ monocytes were quantified by flow cytometry in 42 cord blood samples obtained from the German participants. Bivariate and multivariate regression analyses were performed. Maternal allergies were associated with significantly lower levels of TLR2/4/CD14 mRNA in maternal blood and cord blood samples. Maternal and fetal TLR2/4/CD14 mRNA levels were significantly correlated with each other (TLR2 r = 0.42; TLR4 r = 0.58; CD14 r = 0.54). The results suggest that maternal allergy status may affect allergic risk in offspring through a decreased expression of fetal TLR2/4/CD14.

Adolescent↗
PubMed2005

A role for MCP-1/CCR2 in interstitial lung disease in children.

BACKGROUND: Interstitial lung diseases (ILD) are chronic inflammatory disorders leading to pulmonary fibrosis. Monocyte chemotactic protein 1 (MCP-1) promotes collagen synthesis and deletion of the MCP-1 receptor CCR2 protects from pulmonary fibrosis in ILD mouse models. We hypothesized that pulmonary MCP-1 and CCR2+ T cells accumulate in pediatric ILD and are related to disease severity. METHODS: Bronchoalveolar lavage fluid was obtained from 25 children with ILD and 10 healthy children. Levels of pulmonary MCP-1 and Th1/Th2-associated cytokines were quantified at the protein and the mRNA levels. Pulmonary CCR2+, CCR4+, CCR3+, CCR5+ and CXCR3+ T cells were quantified by flow-cytometry. RESULTS: CCR2+ T cells and MCP-1 levels were significantly elevated in children with ILD and correlated with forced vital capacity, total lung capacity and ILD disease severity scores. Children with lung fibrosis had significantly higher MCP-1 levels and CCR2+ T cells in bronchoalveolar lavage fluid compared to non-fibrotic children. CONCLUSION: The results indicate that pulmonary CCR2+ T cells and MCP-1 contribute to the pathogenesis of pediatric ILD and might provide a novel target for therapeutic strategies.

Adolescent↗
PubMed2005

A generic RNA-pulsed dendritic cell vaccine strategy for renal cell carcinoma.

We present a generic dendritic cell (DC) vaccine strategy for patients with renal cell carcinoma (RCC) based on the use of RNA as a source of multiplex tumor-associated antigens (TAAs). Instead of preparing RNA from tumor tissue of each individual RCC patient, we propose to substitute RNA prepared from a well characterized highly immunogenic RCC cell line (RCC-26 tumor cells) as a generic source of TAAs for loading of DCs. We demonstrate here that efficient RNA transfer can be achieved using lipofection of immature DCs, which are subsequently matured with a cytokine cocktail to express high levels of MHC and costimulatory molecules as well as the chemokine receptor CCR7. Neither RNA itself nor the lipid component impacted on the phenotype or the cytokine secretion of mature DCs. Following RNA loading, DCs derived from HLA-A2-positive donors were able to activate effector-memory cytotoxic T lymphocytes (CTLs) specific for a TAA ligand expressed by the RCC-26 cell line. CTL responses to RNA-loaded DCs reached levels comparable to those stimulated directly by the RCC-26 tumor cells. Furthermore, DCs expressing tumor cell RNA primed naïve T cells, yielding T cell lines with cytotoxicity and cytokine secretion after contact with RCC tumor cells. RCC-26 cell lines are available as good manufacturing practice (GMP)-certified reagents enabling this source of RNA to be easily standardized and adapted for clinical testing. In addition, well defined immune monitoring tools, including the use of RNA expressing B cell lines, are available. Thus, this DC vaccine strategy can be directly compared with an ongoing gene therapy trial using genetically-engineered variants of the RCC-26 cell line as vaccines for RCC patients with metastatic disease.

Journal Article↗
PubMed2005

Cell-based vaccines for renal cell carcinoma: genetically-engineered tumor cells and monocyte-derived dendritic cells.

Initial vaccine developments for renal cell carcinoma (RCC) have concentrated on cell-based approaches in which tumor cells themselves provide mixtures of unknown tumor-associated antigens as immunizing agents. Antigens derived from autologous tumors can direct responses to molecular composites characteristic of individual tumors, whereas antigens derived from allogeneic tumor cells must be commonly shared by RCC. Three types of cell-based vaccine for RCC have been investigated: isolated tumor cell suspensions, gene modified tumor cells and dendritic cells (DCs) expressing RCC-associated antigens. Approaches using genetic modification of autologous RCC have included ex vivo modification of tumor cells or modification of tumors in vivo. We have used gene-modification of allogeneic tumor cell lines to create generic RCC vaccines. More recently, emphasis has shifted to the use of DCs as cell-based vaccines for RCC. DCs have moved to a position of central interest because of their excellent stimulatory capacity, combined with their ability to process and present antigens to both naive CD4 and CD8 cells. The long impasse in identifying molecular targets for specific immunotherapy of RCC is now rapidly being overcome through the use of tools and information emerging from human genome research. Identification of candidate molecules expressed by RCC using cDNA arrays, combined with protein arrays and identification of peptides presented by MHC molecules, allow specific vaccines to be tailored to the antigenic profile of individual tumors, providing the basis for development of patient-specific vaccines.

Cancer Vaccines↗
PubMed2005

Influence of CD80, interleukin-2, and interleukin-7 expression in human renal cell carcinoma on the expansion, function, and survival of tumor-specific CTLs.

PURPOSE: A renal cell carcinoma (RCC) line, RCC-26, has been identified as a suitable candidate for development of an allogeneic tumor cell vaccine based on its expression of a variety of tumor-associated antigens (TAA). To improve immunogenicity, RCC-26 cells were genetically engineered to express CD80 alone or in combination with interleukin (IL)-2 or IL-7. The effect of these modifications on proliferation, function, and survival of autologous and allogeneic tumor-specific CTLs was assessed. EXPERIMENTAL DESIGN: RCC-26 sublines expressing different transgenes were tested for their capacity to reactivate cytokine secretion and cytotoxicity in autologous tumor-infiltrating lymphocytes, to improve proliferation and survival of tumor-associated T cells present in autologous peripheral blood, and to induce tumor-associated responses in naive allogeneic lymphocytes. The expression of several common TAA was quantitated in the RCC-26 sublines using reverse transcription-PCR to identify surrogate markers for immune monitoring in clinical trials. RESULTS: Gene-modified RCC-26 cells showed enhanced immunogenicity. CD80 expression was necessary to induce RCC-associated CTL in blood of healthy allogeneic donors. It also improved proliferation of autologous effector-memory T cells. Further enhancement was achieved with IL-2 through induction of the antiapoptosis protein Bcl-x(L). The candidate vaccine lines overexpressed several common TAA that are suitable markers for immune monitoring. CONCLUSIONS: RCC-26 cells coexpressing CD80 and cytokine transgenes display improved immunogenic characteristics, supporting their use as allogeneic tumor cell vaccines for HLA-A2-matched patients with metastatic RCC.

Antigens, Neoplasm↗
PubMed2005

Pulmonary chemokines and their receptors differentiate children with asthma and chronic cough.

BACKGROUND: Cough is a frequent symptom in children, but the differentiation of asthmatic cough from cough of other origins can be difficult. Chemokines recruit T lymphocytes to inflamed tissues, and the corresponding chemokine receptors are differentially expressed on T H 1 and T H 2 cells. OBJECTIVE: We sought to determine whether levels of T H 1/T H 2-related chemokines and their receptors differ in bronchoalveolar lavage fluid (BALF) from 12 children with allergic asthma, 15 nonatopic children with chronic cough, and 10 children without airway disease. METHODS: The T H 1-related (IFN-gamma-inducible protein of 10 kd [IP-10], IFN-gamma-inducible T cell alpha chemoattractant [ITAC], monokine induced by IFN-gamma [Mig], and IFN-gamma) and T H 2-related (thymus- and activation-regulated chemokine [TARC], macrophage-derived chemokine [MDC], IL-5, and IL-4) chemokines and cytokines were quantified in BALF by ELISA and a particle-based multiplex array. Percentages of pulmonary lymphocytes expressing CXCR3 + and CCR5 + (T H 1) and CCR4 + and CCR3 + (T H 2) chemokine receptors were determined in BALF by flow cytometry. RESULTS: Pulmonary CCR4 + CD4 + cells and levels of TARC and MDC were significantly increased in asthmatic children versus children with chronic cough or without airway disease. In asthmatic children CCR4 + CD4 + cells correlated positively with levels of TARC, MDC, and serum IgE levels and negatively with FEV 1 . In contrast, CXCR3 + CD8 + cells and levels of ITAC were significantly increased in children with non-atopic chronic cough compared with the other groups. In children with chronic cough, CXCR3 + CD8 + cells correlated with levels of ITAC and IFN-gamma. CONCLUSION: Pulmonary CCR4 + CD4 + and CXCR3 + CD8 + cells and their ligands TARC, MDC, and ITAC clearly differentiate asthmatic children from nonatopic children with chronic cough. The analysis of these markers could facilitate the diagnostic discrimination of asthma versus other reasons for chronic cough in children.

Adolescent↗
PubMed2005

RNA transfer by electroporation into mature dendritic cells leading to reactivation of effector-memory cytotoxic T lymphocytes: a quantitative analysis.

Previous studies have analyzed transfer of RNA-encoded tumor-associated antigens (TAAs) into immature dendritic cells (DCs) because of their exceptional ability to internalize antigens. Concerns have been raised regarding the use of immature DCs in clinical studies because of their capacity to tolerize T cells. Therefore, we focused on optimizing RNA transfer into mature DCs using the method of electroporation and obtained high protein expression in 90% of mature DCs. Particular emphasis was placed on quantifying RNA transfer. Reconstitution of peptide-MHC (pMHC) ligands on RNA-pulsed DCs was measured with the help of effector-memory cytotoxic T lymphocytes (CTLs) specific for the melanoma-associated antigens tyrosinase and mutated cyclin-dependent kinase 4. In contrast to single-species RNA, transfer of native tumor-derived RNA or amplified tumor RNA into DCs resulted in very low or no capacity to reactivate these CTLs. A correlation was found between TAA message levels in tumor-derived RNA and pMHC ligand reconstitution on DCs. These results demonstrate that even TAAs with highly immunogenic mutated epitopes are not necessarily transferred when tumor-derived RNA is transfected into the DCs, thereby resulting in a lack of DC capacity to reactivate some preexisting effector-memory CTLs.

Cell Line, Tumor↗
PubMed2005

Redirecting human T lymphocytes toward renal cell carcinoma specificity by retroviral transfer of T cell receptor genes.

Adoptive T cell therapy of renal cell carcinoma (RCC) is limited by the difficulty in generating sufficient numbers of RCC-reactive T cells in vitro. To circumvent this problem, we cloned T cell receptor (TCR) alpha and beta chains from a tumor-infiltrating lymphocyte clone specific for an RCC tumor antigen and transferred the TCR into human T cell lines and primary T lymphocytes. Efficient TCR expression in primary T lymphocytes was obtained only with a mouse myeloproliferative sarcoma virus (MPSV)-based retroviral vector, not with a Moloney murine leukemia virus (MLV)-based vector, although both viral supernatants were similar in titer, as shown by analysis of copy number integration in transduced T cells. Reverse transcription-polymerase chain reaction analysis revealed a higher amount of TCR-encoding transcripts when T cells were transduced with the MPSV vector in comparison with the MLV vector, indicating that high TCR expression levels can be achieved by appropriate cis-regulatory vector elements. The biological activity of the transferred TCR was shown by specific lysis of RCC cells ((51)Cr release assay) and by interferon gamma and tumor necrosis factor alpha release (enzyme-linked immunosorbent assay) in an antigen-specific and HLA-A*0201-restricted fashion. Comparison of the redirected T lymphocytes with the original tumor-infiltrating lymphocyte clone revealed similar killing and cytokine secretion capabilities. The functional activity of TCR-redirected T lymphocytes was stable over time. The results demonstrate that use of an optimized retroviral vector yielded a high TCR transduction efficiency and stable and high TCR expression in primary human T lymphocytes and redirected their specificity toward RCC cells.

Carcinoma, Renal Cell↗
PubMed2003

Renal cell carcinoma-infiltrating natural killer cells express differential repertoires of activating and inhibitory receptors and are inhibited by specific HLA class I allotypes.

Among tumor-infiltrating lymphocytes (TILs) directly isolated from renal cell carcinomas (RCCs), we found substantial numbers of natural killer (NK) cells in most tumor tissues. They could be identified reliably in situ with an antibody directed against the activating receptor (AR) NKp46 that is exclusively expressed by all NK cells. NK-enriched TILs (NK-TILs) showed cytotoxicity against major histocompatibility complex (MHC) class I-negative cell lines. The ability to detect lysis of target cells was dependent on the percentage of NK cells within the TILs, and cytotoxicity was only observed after overnight activation with low-dose interleukin-2 (IL-2). Infiltrating NK cells were found to express various inhibitory receptors (IRs); among these the CD94/NKG2A receptor complex was overrepresented compared to the autologous peripheral blood mononuclear cell (PBMC) population. Other IRs were underrepresented, indicating that NK subpopulations vary in their tumor-infiltrating capacity. IRs expressed by NK-TILs are functional since receptor engagement with MHC class I ligands presented by human leukocyte antigen (HLA)-transfected target cell lines was able to inhibit NK-mediated cytotoxicity. NK-TILs were also able to lyse autologous or allogeneic tumor cell lines in vitro. This activity correlated with low HLA class I surface expression since lysis could be inhibited by interferon (IFN)-gamma-expressing RCC transductants that displayed a higher surface density of HLA class I molecules. Therefore, NK cells infiltrating tumor tissues have an inherent ability to recognize transformed cells, but they require cytokine activation and are sensitive to inhibition by IR ligands.

Antigens, CD↗
PubMed2003

Graft-versus-leukemia reactions in allogeneic chimeras.

There is a strong graft-versus-leukemia (GVL) effect of allogeneic stem cell transplantation (SCT) due to elimination of tumor cells by alloimmune effector lymphocytes. When leukemia relapses after allogeneic SCT, donor lymphocyte transfusions (DLTs) can induce sustained remissions in some patients. This review summarizes the current status on clinical use of DLT, the basis of GVL reactions, problems associated with this therapy, and new strategies to improve DLT. Several multicenter surveys demonstrated that the GVL effect of DLT is most effective in chronic myelogenous leukemia (CML), whereas it is less pronounced in acute leukemia and myeloma. Cytokine stimulation to induce differentiation of myeloid progenitor cells or to up-regulate costimulatory molecules on tumor cells may improve the efficacy of DLT. Infections and graft-versus-host disease (GVHD) are major complications of DLT. Control of GVHD may be improved using suicide gene-modified T cells for DLT, allowing T-cell elimination if severe GVHD develops. Hopefully, in the future, GVL effect can be separated from GVHD through adoptive transfer of selected T cells that recognize leukemia-specific antigens or minor histocompatibility antigens, which are expressed predominantly on hematopoietic cells, thereby precluding attack of normal tissues. In patients with leukemia and lymphomas with fast progression, tumor growth may outpace development of effector T cells. Here it may be preferable to select stem cell transplant donors with HLA-mismatches that allow alloreactive natural killer cells, which appear early after transplantation, to retain their cytolytic function. New approaches for adoptive immune therapy of leukemia, which promise a better prognosis for these patients, are being developed.

Animals↗
PubMed2003

Frequency of Valpha24+CD161+ natural killer T cells and invariant TCRAV24-AJ18 transcripts in atopic and non-atopic individuals.

Th2 cells play a central role in type I allergies. However, the source of interleukin-4 which may lead to a Th1/Th2 imbalance is unknown. Valpha24+CD161+ Natural killer T (NKT) cells secrete high amounts of interleukin-4 and/or interferon-gamma and are assumed to participate in the initiation of Th1/Th2 immune responses. Their contribution to the development of Th2-dependent type I allergies is controversial. Our objective in this paper was to determine whether Valpha24+CD161+ NKT cells differ in atopic and non-atopic adults. Venous blood was obtained from thirteen atopic and sixteen healthy adult probands. Valpha24+CD161+ NKT cells were determined in CD4+, CD8(bright/dim) and CD4-CD8- lymphocytes by flow cytometry. At the molecular level, the amounts of T cell receptor (TCR) AV24-AJ18 transcripts were quantified with respect to TCRAV24 chain transcripts alone or to all TCR alpha chain transcripts. To detect potential inserted nucleotides in the N-region, a novel real-time PCR-based technology was applied. Both CD4+ and CD4-CD8- NKT cells were present at higher frequencies than CD8+ NKT cells in all probands. CD8(dim) NKT cell levels were lower in healthy individuals, although not statistically significantly different to the patients. Amounts of AV24-AJ18 transcripts in relation to total TCR alpha-chains and to TCRAV24 alone were equal in both proband groups. N-region diversity was detected in four clones from four different individuals, but altered the amino acid sequence in only one clone of an atopic donor. Analysis of Valpha24+CD161+ NKT cell frequencies at both the cellular and molecular levels failed to reveal significant differences in peripheral blood of atopic and non-atopic probands. If NKT cells contribute to development of type I allergies they must do so at earlier times or in other locations.

Adult↗