CD1a and antitumour immune response

Integrated Analysis of CD1A Immune Infiltration and Competing Endogenous RNA Networks in COAD

Background

The CD1A gene, a key component of the human immune system and part of the CD1 family, plays a crucial role in presenting lipid antigens to T cells. Abnormal CD1A expression is associated with various immune-related diseases and tumors. However, the biological function of CD1A in COAD is unclear.

Methods

Multiple databases were systematically employed to conduct an analysis of CD1A expression in pan-cancer and COAD, along with its clinical-pathological features. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses of CD1A were performed using the 'clusterProfiler' package. The Protein-protein interaction (PPI) analysis of CD1A was used the STRING database. Additionally, TIMER and ssGSEA tools were used to explore the relationship between CD1A expression in COAD and immune cell infiltration. The study also investigated the association between CD1A expression and N6-methyladenosine (m6A) modification genes in the TCGA COAD cohort and constructed a CD1A-centric competing endogenous RNA (ceRNA) regulatory network.

Results

CD1A displays varying expression levels in various tumors, including COAD, and is closely linked to clinical-pathological characteristics. GO analysis suggests that CD1A plays a role in important processes like antigen processing and presentation, leukocyte-mediated immunity, and lymphocyte-mediated immunity. KEGG analysis identifies CD1A's involvement in key pathways such as the Chemokine signaling pathway and Cytokine-cytokine receptor interaction. PPI analysis highlights CD1A's interactions with CD207, CD1C, CD1E, FOXP3, and ITGB2. ssGSEA analysis indicates a significant relationship between CD1A expression and the infiltration of various immune cells in COAD. Significant associations were found between CD1A and m6A modification genes in COAD. Furthermore, a CD1A-centered ceRNA regulatory network has been constructed.

Conclusion

CD1A emerges as a potential biomarker for the diagnosis and treatment of COAD, showing a strong association with tumor immune infiltration, m6A modification, and the ceRNA network.

Alterations in gene expression and microbiome composition upon calcium-sensing receptor deletion in the mouse esophagus

The calcium-sensing receptor (CaSR), a G protein-coupled receptor, regulates Ca2+ concentration in plasma by regulating parathyroid hormone secretion. In other tissues, it is reported to play roles in cellular differentiation and migration and in secretion and absorption. We reported previously that CaSR can be conditionally deleted in the mouse esophagus. This conditional knockout (KO) (EsoCaSR-/-) model showed a significant reduction in the levels of adherens and tight junction proteins and had a marked buildup of bacteria on the luminal esophageal surface. To further examine the role of CaSR, we used RNA sequencing to determine gene expression profiles in esophageal epithelia of control and EsoCaSR-/-mice RNA Seq data indicated upregulation of gene sets involved in DNA replication and cell cycle in EsoCaSR-/-. This is accompanied by the downregulation of gene sets involved in the innate immune response and protein homeostasis including peptide elongation and protein trafficking. Ingenuity pathway analysis (IPA) demonstrated that these genes are mapped to important biological networks including calcium and Ras homologus A (RhoA) signaling pathways. To further explore the bacterial buildup in EsoCaSR-/- esophageal tissue, 16S sequencing of the mucosal-associated bacterial microbiome was performed. Three bacterial species, g_Rodentibacter, s_Rodentibacter_unclassified, and s_Lactobacillus_hilgardi were significantly increased in EsoCaSR-/-. Furthermore, metagenomic analysis of 16S sequences indicated that pathways related to oxidative phosphorylation and metabolism were downregulated in EsoCaSR-/- tissues. These data demonstrate that CaSR impacts major pathways of cell proliferation, differentiation, cell cycle, and innate immune response in esophageal epithelium. The disruption of these pathways causes inflammation and significant modifications of the microbiome.NEW & NOTEWORTHY Calcium-sensing receptor (CaSR) plays a significant role in maintaining the barrier function of esophageal epithelium. Using RNA sequencing, we show that conditional deletion of CaSR from mouse esophagus causes upregulation of genes involved in DNA replication and cell cycle and downregulation of genes involved in the innate immune response, protein translation, and cellular protein synthesis. Pathway analysis shows disruption of signaling pathways of calcium and actin cytoskeleton. These changes caused inflammation and esophageal dysbiosis.

Exploration of Different Hypoxia Patterns and Construction of a Hypoxia-Related Gene Prognostic Index in Colorectal Cancer

Introduction

Immune checkpoint inhibitor (ICI) therapy has been proven to be a highly efficacious treatment for colorectal adenocarcinoma (COAD). However, it is still unclear how to identify those who might benefit the most from ICI therapy. Hypoxia facilitates the progression of the tumor from different aspects, including proliferation, metabolism, angiogenesis, and migration, and improves resistance to ICI. Therefore, it is essential to conduct a comprehensive understanding of the influences of hypoxia in COAD and identify a biomarker for predicting the benefit of ICI.

Methods

An unsupervised consensus clustering algorithm was used to identify distinct hypoxia-related patterns for COAD patients from TCGA and the GEO cohorts. The ssGSEA algorithm was then used to explore the different biological processes, KEGG pathways, and immune characteristics among distinct hypoxia-related clusters. Some hypoxia-related hub genes were then selected by weighted gene coexpression network analysis (WGCNA). Subsequently, univariate Cox regression analysis, multivariate Cox regression analysis, and least absolute shrinkage and selection operator (LASSO) regression were utilized to construct a hypoxia-related gene prognostic index (HRGPI). Finally, validation was also conducted for HRGPI in prognostic value, distinguishing hypoxia-related characteristics and benefits of ICI.

Results

We identified four hypoxia-related clusters and found that different hypoxia response patterns induced different prognoses significantly. Again, we found different hypoxia response patterns presented distinct characteristics of biological processes, signaling pathways, and immune features. Severe hypoxia conditions promoted activation of some cancer-related signaling pathways, including Wnt, Notch, ECM-related pathways, and remodeled the tumor microenvironment of COAD, tending to present as an immune-excluded phenotype. Subsequently, we selected nine genes (ANO1, HOXC6, SLC2A4, VIP, CD1A, STC2, OLFM2, ATP6V1B1, HMCN2) to construct our HRGPI, which has shown an excellent prognostic value. Finally, we found that HRGPI has an advantage in distinguishing immune and molecular characteristics of hypoxia response patterns, and it could also be an excellent predictive indicator for clinical response to ICI therapy.

Conclusion

Different hypoxia response patterns activate different signaling pathways, presenting distinct biological processes and immune features. HRGPI is an independent prognostic factor for COAD patients, and it could also be used as an excellent predictive indicator for clinical response to ICI therapy.

Does smoking habit affect dendritic cell expression in oral squamous cell carcinoma?

The aim of this study was to determine the presence of immature CD1a+ and mature CD83+ dendritic cells in oral squamous cell carcinoma, to compare immunoreactivity between smokers and nonsmokers, and to correlate the results with histopathological grading. In this observational study, twenty-eight paraffin-embedded biopsies of oral squamous cell carcinoma were retrospectively retrieved and submitted to immunohistochemistry for immature CD1a+ and mature CD83+. Descriptive and statistical analyses were performed. The sample consisted of 18 man (64.3%) and 10 women (35.7%), with a mean age of 64.6 years in the nonsmoker group and 53.2 years in the smoker group. The tongue (11 cases, 39.2%) was the most commonly affected anatomical site, followed by gingiva (6 cases, 21.4%). Histopathological grading revealed 7 low-grade and 7 high-grade malignancy cases in each group, and no correlation with the number of positive DCs. The number of immature CD1a+ was not significantly different between smoker and nonsmoker groups, while a lower number of mature CD83+ was detected in the smoker group (p = 0.001). Smoking changes the oral immune system and decreases the ability to activate and mature dendritic cells, which may influence the development and progression of oral squamous cell carcinoma.

Identification of molecular signatures associated with early relapse after complete resection of lung adenocarcinomas

The only potentially curative treatment for lung adenocarcinoma patients remains complete resection of early-stage tumors. However, many patients develop recurrence and die of their disease despite curative surgery. Underlying mechanisms leading to establishment of systemic disease after complete resection are mostly unknown. We therefore aimed at identifying molecular signatures of resected lung adenocarcinomas associated with the risk of an early relapse. The study comprised 89 patients with totally resected stage IA–IIIA lung adenocarcinomas. Patients suffering from an early relapse within two years after surgery were compared to patients without a relapse in two years. Patients were clinically and molecular pathologically characterized. Tumor tissues were immunohistochemically analyzed for the expression of Ki67, CD45, CD4, CD8, PD1, PD-L1, PD-L2 and CD34, by Nanostring nCounter PanCancer Immune Profiling Panel as well as a comprehensive methylome profiling using the Infinium MethylationEPIC BeadChip. We detected differential DNA methylation patterns as well as significantly differentially expressed genes associated with an early relapse after complete resection. Especially, CD1A was identified as a potential biomarker, whose reduced expression is associated with an early relapse. These findings might help to develop biomarkers improving risk assessment and patient selection for adjuvant therapy as well as establish novel targeted therapeutic strategies.

Density of Langerhans Cells in Nonmelanoma Skin Cancers: A Systematic Review

Langerhans cells (LCs) are bone marrow-derived dendritic cells (DCs) that represent 2-3% of the entire cell population of the human skin, known to have an ability to present antigens to T lymphocytes. Moreover, there is evidence that LCs are probably capable of inducing the local cytotoxic type T-cell-mediated response against the tumour-associated antigens. In the past two decades, a dramatic increase has been noted in the incidence of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). The purpose of this study was to critically assess the results of available studies quantitatively assessing the LCs in nonmelanoma skin cancers and try to establish a conclusion of its possible impact on their future treatment. The PubMed, EMBASE, and the Web of Science databases were searched, which returned 948 citations. After a thorough analysis of full article texts, 30 studies have been chosen, including 11 of the BCC, 12 of the SCC specimens, and 7 analysing both tumour types. There was an overall trend towards slightly higher numbers of LCs in BCC than in SCC; however, these tendencies were discrepant between the studies. We presume that such differences could be caused by various staining techniques with a broad spectrum of specificity, including anti-S100, anti-CD1a, and ATPase activity staining used for LCs identification. We hypothesise that as there is a high inconsistency between the results of the studies, as far as the densities of LCs observed in the specimens are concerned, it seems that the mechanism of the influence of LCs on the antitumoural immune response is complicated. Finally, as at present, there is a paucity of available risk scores for the recurrence or progression of BCC or SCC, the creation of classification stratifying that risk including the density of LCs could bring additional information both for the physician and the patient.

Mature dendritic cell density is affected by smoking habit, lesion size, and epithelial dysplasia in oral leukoplakia samples

OBJECTIVE

To compare the densities of CD1a + immature and CD83+ mature dendritic cells, and inflammatory infiltrate cells between smokers and non-smokers with oral leukoplakia. Parameters associated with malignant transformation were also evaluated.

DESIGN

21 smokers and 23 non-smokers diagnosed with oral leukoplakia were obtained. Densities of inflammatory infiltrate cells were calculated in H&E sections. Immunohistochemistry using anti-CD1a and anti-CD83 was performed and densities were calculated. Comparisons and statistical analyses were performed among the groups and parameters as gender, lesion size, site, and presence of cell dysplasia were analyzed.

RESULTS

A lower density of CD83+ cells was observed in smokers compared to non-smokers (P < 0.05). For samples of smokers, a lower density of CD1a + cells, CD83+ cells, and inflammatory infiltrate cells was observed in samples with <10 mm compared to samples ≥10 mm of diameter (P < 0.05), and a lower density of CD83+ cells was also observed between samples without dysplasia compared to samples with dysplasia (P < 0.05).

CONCLUSION

In oral leukoplakia samples, dendritic cell density decreases in the presence of smoking habit, and increases in larger lesions and with epithelial dysplasia. Smoking habit is an external factor that contribute to alteration of the anti-tumoral immune defense system in lesions of oral leucoplakia, reinforcing that smoking elimination is important to control the development of this disease.

Defining Genome-Wide Expression and Phenotypic Contextual Cues in Macrophages Generated by Granulocyte/Macrophage Colony-Stimulating Factor, Macrophage Colony-Stimulating Factor, and Heat-Killed Mycobacteria

Heat-killed (HK) Mycobacterium obuense (NCTC13365) is currently being evaluated in the clinic as an immunotherapeutic agent for cancer treatment. Yet, the molecular underpinnings underlying immunomodulatory properties of HK M. obuense are still largely undefined. To fill this void, we sought to perform immunophenotyping, chemokine/cytokine release analysis and genome-wide characterization of monocyte-derived macrophages (MDM) in which monocytes were originally isolated from healthy donors and differentiated by HK M. obuense (Mob-MDM) relative to macrophage colony-stimulating factor (M-MDM) and granulocyte/macrophage colony-stimulating factor (GM-MDM). Immunophenotyping and cytokine release analysis revealed downregulated surface expression of CD36, decreased spontaneous release of CCL2 and increased spontaneous secretion of CCL5, CXCL8/IL-8, IL-6, and TNF-α in Mob-MDM relative to M-MDM and GM-MDM. Analysis of cytostatic activity showed that Mob-MDM exhibited similar growth inhibitory effects on immortalized and malignant epithelial cells compared with GM-MDM but at an elevated rate relative to M-MDM. To understand global cues in Mob-MDM, we performed comparative RNA-sequencing (RNA-Seq) analysis of Mob-MDM relative to GM-MDM and M-MDM (n = 4 donors). Clustering analysis underscored expression profiles (n = 256) that were significantly modulated in Mob-MDM versus both M-MDM and GM-MDM including, among others, chemokines/cytokines and their receptors, enzymes and transcriptions factors. Topological functional analysis of these profiles identified pathways and gene sets linked to Mob-MDM phenotype including nitric oxide production, acute phase response signaling and microbe recognition pathways as well as signaling cues mediated by the proinflammatory cytokine, interferon-gamma, and the intracellular pattern recognition receptor, nucleotide-binding oligomerization domain-containing protein 2. Taken together, our study highlights molecular immune phenotypes and global signaling cues in Mob-MDM that may underlie immunomodulatory properties of HK M. obuense. Such properties could be of valuable use in immunotherapy approaches such as adoptive cell therapy against cancer.

CD1a+ and CD83+ Langerhans cells are reduced in lower lip squamous cell carcinoma

BACKGROUND

Actinic cheilitis (AC) is a potentially malignant lesion diagnosed in the lip of patients chronically exposed to the sun that may give rise to a fully invasive lower lip squamous cell carcinoma (LLSCC). It is known that ultraviolet radiation causes dendritic cells (DCs) depletion in the epidermis, but the role of this cellular population in lip cancer progression remains uncertain. Therefore, this study investigated the distribution of DCs in normal, dysplastic and neoplastic tissues of the lower lip.

METHODS

Thirteen cases of lower lip mucocele, 42 of ACs and 21 of LLSCC were retrieved and original diagnoses confirmed by two oral pathologists, who further classified ACs as low- and high-risk lesions. Immunoreactions against CD1a and CD83 identified immature and mature DCs, respectively.

RESULTS

Immature CD1a+ Langerhans cells (LCs) were significantly decreased in LLSCC when compared to morphologically normal (P < 0.009) and dysplastic epitheliums (P < 0.003), whereas mature CD83+ LCs were significantly decreased in LLSCC when compared to normal epithelium (P = 0.038). There was no significant difference between low- and high-risk ACs regarding CD1a+ and CD83+ LCs (P > 0.05), but ACs demonstrated a lower concentration of CD1a+ LCs than normal epithelium (P < 0.009). There was no significant difference in the distribution of CD1a+ and CD83+ interstitial dendritic cells (IDCs) in the connective tissue among the studied groups (P > 0.05).

CONCLUSION

These results suggest that depletion of epithelial LCs, but not IDCs in the connective tissue, would represent an important step for lip cancer development.

Characterization of dendritic cells in lip and oral cavity squamous cell carcinoma

BACKGROUND

There may be differences in the antitumor immunity induced by dendritic cells (DCs) during the development of squamous cell carcinoma (SCC) located in the lip rather than in the oral cavity. The aim of this study was to evaluate the number of immature and mature DCs in SCC and potentially malignant disorders of the oral cavity and lip.

METHODS

Immunohistochemistry was used to identify the number (cells/mm(2) ) of immature (CD1a(+) ) or mature (CD83(+) ) DCs in samples of oral cavity SCC (OCSCC) (n = 39), lip SCC (LSCC) (n = 23), leukoplakia (LK) (n = 21), actinic cheilitis (AC) (n = 13), and normal mucosa of the oral cavity (OC control, n = 12) and the lip (lip control, n = 11).

RESULTS

The number of CD1a(+) cells tended to be higher in the OC control samples compared with the LK (P = 0.04) and OCSCC (P = 0.21). Unlike, this cell population was lower in the lip control than in AC or LSCC (P < 0.05). The number of CD83(+) cells was increased in the LSCC samples compared with the AC and lip control (P = 0.0001) and in OCSCC compared with both the LK (P = 0.001) and OC control (P = 0.0001) samples. LSCC showed an elevated number of CD1a(+) and CD83(+) cells compared with OCSCC (P = 0.03). The population of mature DCs was lower than the population of immature DCs in all of the tested groups (P < 0.05).

CONCLUSION

There were a greater number of both mature and immature DC populations in the LSCC samples than in the OCSCC, which could contribute to establishing a more effective immune antitumor response for this neoplasm.

CD1a-positive dendritic cell density predicts disease-free survival in papillary thyroid carcinoma

OBJECTIVES

Dendritic cells are common in inflammatory processes and in papillary thyroid carcinoma (PTC). Previous studies of the predictive value of S100-positive dendritic cell density for PTC outcome yielded inconsistent results. This study investigated the association of dendritic cell density and PTC recurrence based on CD1a expression.

METHODS

Representative slides from 56 consecutive specimens of PTC were immunostained with anti-CD1a antibodies, and dendritic cell density was analyzed by disease-free survival.

RESULTS

Dendritic cells were abundant in the tumoral tissue and sparse in the normal peritumoral tissue. Peritumoral dendritic cell density >1.1 cells/HPF was inversely associated with the risk of recurrence. Similar results were obtained with tumoral dendritic cell density (>12 cells/HPF), although the statistical significance was marginal.

CONCLUSIONS

High CD1a-positive dendritic cell density is associated with improved disease-free survival in PTC. The specificity of anti-CD1a immunostain for activated dendritic cells may explain the better outcome prediction in this study than in studies using S100 protein.

The distribution of immunomodulatory cells in the lungs of patients with idiopathic pulmonary fibrosis

We have characterized the immune system involvement in the disease processes of idiopathic pulmonary fibrosis in novel ways. To do so, we analyzed lung tissue from 21 cases of idiopathic pulmonary fibrosis and 21 (non-fibrotic, non-cancerous) controls for immune cell and inflammation-related markers. The immunohistochemical analysis of the tissue was grouped by patterns of severity in disease pathology. There were significantly greater numbers of CD68(+) and CD80(+) cells and significantly fewer CD3(+), CD4(+), and CD45RO(+) cells in areas of relatively (histologically) normal lung in biopsy samples from idiopathic pulmonary fibrosis patients compared with controls. In zones of active disease, characterized by epithelial cell regeneration and fibrosis, there were significantly more cells expressing CD4, CD8, CD20, CD68, CD80, chemokine receptor 6 (CCR6), S100, IL-17, tumor necrosis factor-α, and retinoic acid-related orphan receptors compared with histologically normal lung areas from idiopathic pulmonary fibrosis patients. Inflammation was implicated in these active regions by the cells that expressed retinoid orphan receptor-α, -β, and -γ, CCR6, and IL-17. The regenerating epithelial cells predominantly expressed these pro-inflammatory molecules, as evidenced by co-expression analyses with epithelial cytokeratins. Macrophages in pseudo-alveoli and CD3(+) T cells in the fibrotic interstitium also expressed IL-17. Co-expression of IL-17 with retinoid orphan receptors and epithelial cytoskeletal proteins, CD68, and CD3 in epithelial cells, macrophages, and T-cells, respectively, confirmed the production of IL-17 by these cell types. There was little staining for forkhead box p3, CD56, or CD34 in any idiopathic pulmonary fibrosis lung regions. The fibrotic regions had fewer immune cells overall. In summary, our study shows participation of innate and adaptive mononuclear cells in active-disease regions of idiopathic pulmonary fibrosis lung, where the regenerating epithelial cells appear to propagate inflammation. The regenerative mechanisms become skewed to ultimately result in lethal, fibrotic restriction of lung function.

Clinical significance of langerhans cells in squamous cell carcinoma of the larynx

Langerhans cells (LCs) may be involved in the immunosurveillance against tumors as antigen-presenting cells. Our objective has been to determine the relevance of LC in progression of larynx squamous cell carcinomas and their relationship with different subpopulations of tumor-infiltrating cells. LCs were investigated by immunohistochemical methods using anti-CD1 antibody. LCs were detected in most of the primary tumors studied (44 out of 50) and also in metastases (6 out of 10) and recurrences (2 out of 3), but we did not find any statistical association between number of LCs and clinical-pathological parameters or survival. However, the number of LCs was increased in patients with evident infiltration of lymphocytes, mainly cytotoxic T cells. We can conclude that although LCs did not show clinical utility as prognostic marker, they may play a role in releasing an active immune response in larynx carcinomas, according to their ability to present antigens to sensitized T cells.

The melanocortin receptor agonist NDP-MSH impairs the allostimulatory function of dendritic cells

As alpha-melanocyte-stimulating hormone (alpha-MSH) is released by immunocompetent cells and has potent immunosuppressive properties, it was determined whether human dendritic cells (DCs) express the receptor for this hormone. Reverse transcription-polymerase chain reaction detected messenger RNA specific for all of the known melanocortin receptors in DCs. Mixed lymphocyte reactions also revealed that treatment with [Nle(4), DPhe(7)]-alpha-MSH (NDP-MSH), a potent alpha-MSH analogue, significantly reduced the ability of DCs to stimulate allogeneic T cells. The expression of various cell surface adhesion, maturation and costimulatory molecules on DCs was also investigated. Although treatment with NDP-MSH did not alter the expression of CD83 and major histocompatibility complex class I and II, the surface expression of CD86 (B7.2), intercellular adhesion molecule (ICAM-1/CD54) and CD1a was reduced. In summary, our data indicate that NDP-MSH inhibits the functional activity of DCs, possibly by down-regulating antigen-presenting and adhesion molecules and that these events may be mediated via the extracellular signal-regulated kinase 1 and 2 pathway.

The prognostic value of intraepithelial and stromal innate immune system cells in non-small cell lung carcinoma

AIMS

The major value of prognostic markers in potentially curable non-small cell lung carcinoma (NSCLC) should be to guide therapy after surgical resection. The prognostic significance of tumour-infiltrating macrophages, their growth factor, macrophage colony-stimulating factor (M-CSF), and its receptor, colony-stimulating factor-1 receptor (CSF-1R), as well as natural killer cells and dendritic cells, is controversial. The aim of this study was to elucidate the prognostic significance of these markers in the epithelial and stromal compartments of NSCLC.

METHODS AND RESULTS

Tissue microarrays from 335 resected NSCLC, stage I-IIIA were constructed from duplicate cores of epithelial and stromal areas. Immunohistochemistry was used to evaluate epithelial and stromal areas for CD68, M-CSF, CSF-1R, CD56 and CD1a. On univariate analysis, increasing numbers of stromal CD1a+ (P = 0.011) and CD56+ cells (P = 0.014) correlated significantly with improved disease-specific survival (DSS). On multivariate analysis, stromal CD56+ cells were an independent prognostic factor for DSS (hazard ratio = 2.3, confidence interval = 1.1, 5.0, P = 0.031).

CONCLUSIONS

High density of stromal CD56+ cells is an independent factor associated with improved prognosis in resected NSCLC, suggesting that these cells mediate an antitumour immune response in the tumour stroma.

Sphingosine 1-phosphate as a novel immune regulator of dendritic cells

Although originally described as an intracellular second messenger, sphingosine 1-phosphate (S1P) has recently been shown to be involved in several physiological and pathological functions as an extracellular mediator. S1P receptors are widely expressed and thought to regulate important functions in cell signalling. Recently, the role of S1P on the immune system has evoked great interest. In particular, several aspects of the effects on antigen-presenting cells (APCs) as dendritic cells (DC) in mice and humans have been reported. In this review, we focus on the role played by S1P on the DC system and its effects in immune-related pathological states.

Sphingosine 1-Phosphate Interferes on the Differentiation of Human Monocytes into Competent Dendritic Cells

Sphingosine 1-phosphate (S1P) is a lipidic messenger known to exert several physiological functions within the cell. We tested here whether the stimulation of human monocytes with different doses of S1P might interfere with their differentiation into competent dendritic cells (DC). Monocytes cultured with granulocyte macrophage colony stimulating factor, interleukin-4 (IL-4) and S1P differentiated into a DC population lacking CD1a molecules on the surface and acquired some aspects of mature DC (mDC), though in the absence of maturation stimuli. When stimulated with lipopolisaccharide (LPS), CD1a(-) DC produce high amounts of tumour necrosis factor-alpha and IL-10, but not IL-12. Accordingly, these CD1a(-) DC were not capable of stimulating allogenic T lymphocytes so well as CD1a(+) DC generated from untreated monocytes and maturated with LPS. S1P monocyte-derived DC lost their polarizing capacity abrogating the production of gamma-interferon/IL-4 by co-cultured naïve CD4(+)CD45RA(+) T cells. Our findings suggest a mechanism through which S1P can favour the development of immune-related pathological states.

Influence of Pertussis toxin on CD1a Isoform Expression in Human Dendritic Cells

Pertussis toxin (PTX) is an exotoxin produced by Bordetella pertussis. It is known to exert adjuvant activities inducing Th1-launched immune responses. In this study, we show that PTX can selectively block the expression of CD1a isoform during the differentiation of human monocytes into dendritic cells. In fact, dendritic cells differentiated from monocytes in the presence of PTX do not express CD1a on their surface, unlike CD1b and CD1c isoforms, which are normally regulated. The impaired CD1a expression on cell membrane depends, at least partially, on decreased mRNA transcription and does not affect cellular capability to respond to other maturation stimuli. Since CD1a(+) dendritic cells are involved in the early steps of primary immune response, the interference of PTX in the CD1a expression may be relevant for its employment as adjuvant.

CD1a expression by Barrett's metaplasia of gastric type may help to predict its evolution towards cancer

As emerging in the recent literature, CD1a has been regarded as a molecule whose expression may reflect tumour evolution. The aim of the present work was to investigate the expression of CD1a in a series of Barrett's metaplasia (BM), gastric type (GTBM), with and without follow-up, in order to analyse whether its expression may help to diagnose this disease and to address the outcome. Indeed, GTBM may be confused sometimes with islets of ectopic gastric mucosa and its evolution towards dysplasia (Dy) or carcinoma (Ca) could not be foreseen. We showed a significant higher expression of CD1a in GTBM than in both Dy and Ca; nevertheless, the number of positive GTBM was significantly lower in the group of cases that at follow-up underwent Dy or Ca. Our data address that CD1a may be a novel biomarker for BM and that its expression may help to predict the prognosis of this pathology.