Dendritic cells interacting mainly with B cells in the lymphoepithelial symbiosis of the human palatine tonsil

Tissue-specific antigen-presenting cells contribute to distinct phenotypes of allergy

Antigen-presenting cells (APCs) are critical cells bridging innate and adaptive immune responses by taking up, processing, and presenting antigens to naïve T cells. At steady state, APCs thus control both tissue homeostasis and the induction of tolerance. In allergies however, APCs drive a Th2-biased immune response that is directed against otherwise harmless antigens from the environment. The main types of APCs involved in the induction of allergy are dendritic cells, monocytes, and macrophages. However, these cell types can be further divided into local, tissue-specific populations that differ in their phenotype, migratory capacity, T-cell activating potential, and production of effector molecules. Understanding if distinct populations of APCs contribute to either tissue-specific immune tolerance, allergen sensitization, or allergic inflammation will allow us to better understand disease pathology and develop targeted treatment options for different stages of allergic disease. Therefore, this review describes the main characteristics, phenotypes, and effector molecules of the APCs involved in the induction of allergen-specific Th2 responses in affected barrier sites, such as the skin, nose, lung, and gastrointestinal tract. Furthermore, we highlight open questions that remain to be addressed to fully understand the contribution of different APCs to allergic disease.

Growing role of S100B protein as a putative therapeutic target for neurological- and nonneurological-disorders

S100B is a calcium-binding protein mainly expressed by astrocytes, but also localized in other definite neural and extra-neural cell types. While its presence in biological fluids is widely recognized as a reliable biomarker of active injury, growing evidence now indicates that high levels of S100B are suggestive of pathogenic processes in different neural, but also extra-neural, disorders. Indeed, modulation of S100B levels correlates with the occurrence of clinical and/or toxic parameters in experimental models of diseases such as Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, muscular dystrophy, multiple sclerosis, acute neural injury, inflammatory bowel disease, uveal and retinal disorders, obesity, diabetes and cancer, thus directly linking the levels of S100B to pathogenic mechanisms. In general, deletion/inactivation of the protein causes the improvement of the disease, whereas its over-expression/administration induces a worse clinical presentation. This scenario reasonably proposes S100B as a common therapeutic target for several different disorders, also offering new clues to individuate possible unexpected connections among these diseases.

U-DCS: characterization of the first permanent human dendritic sarcoma cell line

A dendritic cell sarcoma cell line, U-DCS, was established from a dendritic cell sarcoma in a 53-year-old Caucasian male patient. Since its establishment, U-DCS has maintained stable phenotypic characteristics in vitro and has a doubling time of approximately 2 days under standard culture conditions. U-DCS is growing with typical dendritic cell morphology in tissue and expresses the dendritic cell sarcoma immunophenotypic markers S100 protein, MHCI, MHCII, and vimentin. Expression analysis revealed transcripts for the toll-like receptors TLR3, -4, -9 and DDX58 (RIG-I), but not for TLR2. U-DCS shows functional features of dendritic cells with the ability of phagocytosis and antigen-specific T cell stimulation. Karyotype-, CGH-, and mFISH analysis point to a chromosomal instability and a hypotetraploid karyotype with approximately 130 chromosomes. U-DCS is the first immortalized human dendritic cell sarcoma cell line and has some morphological and functional features of dendritic cells without dependency on growth factors.

Microneedle-Mediated Vaccine Delivery to the Oral Mucosa

The oral mucosa is a minimally invasive and immunologically rich site that is underutilized for vaccination due to physiological and immunological barriers. To develop effective oral mucosal vaccines, key questions regarding vaccine residence time, uptake, adjuvant formulation, dose, and delivery location must be answered. However, currently available dosage forms are insufficient to address all these questions. An ideal oral mucosal vaccine delivery system would improve both residence time and epithelial permeation while enabling efficient delivery of physicochemically diverse vaccine formulations. Microneedles have demonstrated these capabilities for dermal vaccine delivery. Additionally, microneedles enable precise control over delivery properties like depth, uniformity, and dosing, making them an ideal tool to study oral mucosal vaccination. Select studies have demonstrated the feasibility of microneedle-mediated oral mucosal vaccination, but they have only begun to explore the broad functionality of microneedles. This review describes the physiological and immunological challenges related to oral mucosal vaccine delivery and provides specific examples of how microneedles can be used to address these challenges. It summarizes and compares the few existing oral mucosal microneedle vaccine studies and offers a perspective for the future of the field.

Decreased CD1a(+) , CD83(+) and factor XIIIa(+) dendritic cells in cervical lymph nodes and palatine tonsils of AIDS patients

AIMS

The purpose of this study was to quantify and compare the density of dendritic cells (DCs) in cervical lymph nodes (LNs) and palatine tonsils (PTs) of AIDS and non-AIDS patients.

METHODS AND RESULTS

Factor XIIIa, CD1a and CD83 antibodies were used to identify migratory DCs by immunohistochemistry in LNs and PTs of 32 AIDS patients and 21 HIV-negative control patients. Quantification was performed by the positive pixel count analytical method. AIDS patients presented a lower density of factor XIIIa(+) cells (P < 0.001), CD1a(+) cells (P < 0.05) and CD83(+) cells (P < 0.001) in cervical LNs and PTs compared to the non-AIDS control group.

CONCLUSION

Overall depletion of DCs in lymphoid tissues of AIDS patients may be predictive of the immune system's loss of disease control.

[Dendritic cells in hypertrophied adenoid at children with otitis media with effusion]

INTRODUCTION

The adenoids are organized as lymphoepithelial structures that play an important role in protecting both the upper respiratory and alimentary tract regions. This functions requires dendritic cells (DC) which are one of the major populations of immune cells. Due to the presence of specific receptors (DC) are able to respond to both intra- and extracellular antigens. Dendritic cells activating immunological response in tonsil contribute formation immunologic competent cells on necessity of rolling inflammatory process in middle ear.

AIM OF STUDY

An investigation was executed in hypertrophied adenoids with or without otitis media with effusion.

METHODS

By flow cytometry percentage of CD11c+ myeloid DC and 123+ plasmacytoid DC in hypertrophied adenoid and hypertrophied adenoid and otitis media with effusion was analyzed.

RESULTS

The percentage of CD11c+ myeloid DC and 123+ plasmacytoid DC was similar in hypertrophied adenoid and otitis media with effusion compored to the control group.

CONCLUSIONS

Our data show that part of dendritic cells has not on course of inflammatory process influence rolling in middle ear.

Immunohistochemical discrimination of plasmacytoid dendritic cells from myeloid dendritic cells in human pathological tissues

Until now, no method has been available to discriminate mature plasmacytoid DC (pDC) from myeloid DC (mDC) immunohistochemically. In this study, we report that these DC-subsets can be distinguished in routine pathological sections. Immature and mature monocyte-derived DCs (MoDCs) were S100 calcium binding protein B (S100B)+, while pDCs generated from pDC-precursors were S100B-. In contrast, both mature MoDC and pDC were fascin+. Epidermal Langerhans cells (LCs) were S100B+/fascin-. Although the majority of DCs were S100B+/fascin+ in the dermis with nonspecific inflammation, dermal DCs were mostly S100B-/fascin+ in psoriasis vulgaris, in which type I interferon secreted by pDC-precursors is thought to play a major role. S100B+/fascin+ DCs were accumulated in the superficial lymph node (LN), while they were scarce in the deep LN. In the superficial LN with dermatopathic lymphadenitis, a large number of S100B+/fascin+ DCs were accumulated in the T-zones, where numerous LC-derived DCs are accumulated. In contrast, almost all DCs were S100B-/fascin+ in the superficial LN with Kikuchi's lymphadenitis, in which numerous pDC-precursors are known to be present. In contrast to the superficial LN, the deep LN contained numerous S100B-/fascin+ DCs and a few S100B+ DCs. Thus, the distributions of S100B+ DC or S100B-/fascin+ DC correspond to the putative distribution of mDC or mature pDC, respectively.

Identification and characterization of human thymic cortical dendritic macrophages that may act as professional scavengers of apoptotic thymocytes

We identify and characterize a special type of macrophage in the human thymic cortex that may act as professional scavengers of apoptotic thymocytes. These are large cells with clear cytoplasm, evenly distributed exclusively in the thymic cortex, and usually contain degraded nuclei in their cytoplasm. They are distinct from ordinary macrophages (OM) in the thymic cortex in expressing fascin, an actin-bundling protein specific for dendritic cells (DC), and in lacking lysozyme (LZM) and CD68. They are also different from DC in lacking major histocompatibility complex (MHC)-class II molecules. To distinguish them from OM and DC, we called them thymic cortical dendritic macrophages (TCDM). Both TCDM and OM are positive for DC-SIGN (CD209) and HAM56, whereas fascin(hi) MHC-class II(hi) medullary DC (mDC) are negative for these antigens. TCDM exhibit either dendritic or plump feature depending on cases examined. Plump TCDM usually contain several degraded nuclei, while dendritic TCDM contain one or two. These degraded nuclei are positive for active caspase-3 (aCasp-3), indicating that they are apoptotic thymocytes. In contrast to TCDM, LZM(hi) CD68(hi) OM are smaller round cells, distributed unevenly throughout the thymus, and do not contain apoptotic thymocytes at all. TCDM tend to adhere to capillaries with their dendrites or they make extensive contacts covering a large portion of the capillaries. Electron microscopic analysis confirmed the extensive contact between TCDM and capillaries and indicated that TCDM possess extremely electron-lucent, abundant cytoplasm with numerous tubulovesicular structures and secondary lysosomes. The finding of numerous condensed nuclei in most of the TCDM indicates that these cells represent a special type of fixed macrophages in the human thymic cortex, and that they play a central role in the clearance of apoptotic thymocytes.

Mucosal dendritic cells

The internal surfaces of the human body are covered by distinct types of epithelial cells and mucus-secreting cells. The mucosal surfaces serve many vital functions, such as respiration (nasal passage and lung), absorption (gastrointestinal tract), excretion (lung, urinary tract, large intestine), and reproduction (reproductive tract). In performing these functions, the host is inevitably exposed to environmental antigens, food particles, commensal flora, and pathogens. Mucosal surfaces contain specialized dendritic cells (DCs) capable of sensing these external stimuli and mounting appropriate local responses depending on the nature of the elements they encounter. In the absence of pathogens, mucosal DCs either ignore the antigen or induce regulatory responses. Upon recognition of microorganisms that invade the mucosal barrier, mucosal DCs mount robust protective immunity. This review highlights progress in our understanding of how mucosal DCs process external information and direct appropriate responses by mobilizing various cells of the innate and adaptive immune systems to achieve homeostasis and protection.