Detection of JC Virus DNA in Human Tonsil Tissue: Evidence for Site of Initial Viral Infection

Progressive multifocal leukoencephalopathy is a demyelinating disease of the human central nervous system that results from lytic infection of oligodendrocytes by the polyomavirus JC (JCV). Originally, JCV was thought to replicate exclusively in human glial cells, specifically oligodendrocytes. However, we have recently shown that JCV can replicate in cells of lymphoid origin such as hematopoietic precursor cells, B lymphocytes, and tonsillar stromal cells. To determine whether tonsils harbor JCV, we tested a total of 54 tonsils, 38 from children and 16 from adult donors. Nested PCRs with primer sets specific for the viral T protein and regulatory regions were used for the detection of JCV DNA. JCV DNA was detected in 21 of 54 tonsil tissues, or 39% (15 of 38 children and 6 of 16 adults) by using regulatory-region primers and in 19 of 54 tonsil tissues, or 35% (13 of 38 children and 6 of 16 adults) by using the T-protein primers. The DNA extracted from children’s nondissected tonsil tissue, isolated tonsillar lymphocytes, and isolated stromal cells that demonstrated PCR amplification of the JCV regulatory region underwent cloning and nucleotide sequencing. Of the regulatory-region sequences obtained, nearly all contained tandem repeat arrangements. Clones originating from nondissected tonsil tissue and tonsillar lymphocytes were found to have sequences predominantly of the Mad-1 prototype strain, whereas the majority of clones from the DNA of tonsillar stromal cells had sequences characteristic of the Mad-8_br strain of JCV. A few clones demonstrated structures other than tandem repeats but were isolated only from tonsillar lymphocytes. These data provide the first evidence of the JCV genome in tonsil tissue and suggest that tonsils may serve as an initial site of viral infection.     

Embryogenesis of the human pharyngeal tonsil

By means of histological, histochemical, immunological and morphometric methods 78 pharyngeal tonsils of human embryos at the age of 12-40 weeks have been investigated. The character of the organ's anlage at 12-14 weeks of development as longitudinal folds on the dorsal wall of the rhinopharynx and changes in correlation of the lymphoid and epithelial tissues are presented in the process of the tonsil embryogenesis. Occupation of the organ with lymphocytes takes place on the 16th week of development. The embryos possess already two classes of T- and B-lymphocytes and their subclasses: auto-E-RFC, EAC-RFC, IgM and IgG positive cells; their kinetics is demonstrated in the process of the organ's development. A comparison on lymphocyte quantity, participating in cell-dependent immunity of the tonsil in fetuses, children and mature persons is presented.     

Optical Coherence Tomography and Autofluorescence Imaging of Human Tonsil

For the first time, we present co-registered autofluorescence imaging and optical coherence tomography (AF/OCT) of excised human palatine tonsils to evaluate the capabilities of OCT to visualize tonsil tissue components. Despite limited penetration depth, OCT can provide detailed structural information about tonsil tissue with much higher resolution than that of computed tomography, magnetic resonance imaging, and Ultrasound. Different tonsil tissue components such as epithelium, dense connective tissue, lymphoid nodules, and crypts can be visualized by OCT. The co-registered AF imaging can provide matching biochemical information. AF/OCT scans may provide a non-invasive tool for detecting tonsillar cancers and for studying the natural history of their development.     

4种平胸鸟类腰荐部骨骼的比较

对鹤鸵(Casuarius casuarius)、鸸鹋(Dromaius novaehollandiae)、美洲鸵鸟(Rhea americana)和鸵鸟(Struthio camelus)的腰荐部骨骼进行了对比。鸸鹋与鹤鸵在愈合荐骨的数目与构成、腰带的结构方面最为相似,均为开放式骨盆。美洲鸵鸟和鸵鸟均为非开放式骨盆,前者的坐骨大部愈合,后者的耻骨后角左右愈合。与突胸鸟类对比发现:平胸类的愈合荐骨相对较长,髂骨后翼狭窄、几乎垂直伸向下方;突胸鸟类的髂骨后翼宽阔、水平侧向伸展并微微向背方拱起。反映了平胸类结构的原始性。     

On the variability of velopharyngeal valve anatomy and function: a combined peroral and nasendoscopic study.

The oropharynx stripped of the tonsils and the excessive mucosal folds after the uvulopalatopharyngoplasty operation allows a closed observation of the outline of the pharyngeal muscles. Forty-two consecutive patients undergoing uvolopalatopharyngoplasty were subjected to peroral examination of the oropharynx combined with nasendoscopic examination of the velopharyngeal valve. At rest, the oropharynx of the patients with coronal closure patterns was found to be flat relative to the oropharynx of the patients with the other closure patterns. During closure of the velopharyngeal valve, an anteroposterior movement of the velum, forming the nasendoscopic coronal closure pattern, was observed in patients with a flat oropharynx. On the other hand, a medial movement of the pharyngeal walls was found, forming the circular or sagittal closure pattern seen in patients with a deep oropharynx. Our conclusion is therefore that a different muscular orientation is responsible for both the different pharyngeal configuration at rest and the different contribution of the lateral and posterior pharyngeal walls to velopharyngeal valve closure.     

Morphology of complex lymphoepithelial organs of the anal canal (“anal tonsil”) in the bottlenose dolphin,Tursiops truncatus

A complex of lymphoepithelial organs, the “anal tonsils,” is a consistent structure in the anal canal of the bottlenose dolphin, Tursiops truncatus. This complex occurs as a circumferential cluster of discrete tonsil like aggregations of lymphoid tissues, together with epithelial ducts (“crypts”) and occasional mucus secretory units in the extreme lower portion of the intestinal tract. These structures are concentrated in the segment lined by stratified squamous epithelium and extend for a variable distance cephalad from the anal aperture. The tonsils appear to be most active, judged by the amount of lymphoid tissue present, in young animals. Depletion of lymphocytes and cystic enlargement of the crypts, probably representing functional as well as morphological involution, is a consistent feature of older animals. © 1995 Wiley-Liss, Inc.     

Histological studies on the development of porcine tonsils after birth

Tonsils form the topographically first immune barrier of an organism against the invasion of pathogens. We used histology to study the development of tonsils of pigs after birth. At birth, the tonsils consist of diffuse lymphoid tissue without any lymphoid follicle aggregations. At the age of 7 days, lymphoid follicles appeared in the soft palate tonsil. The lymphoid layer of the nasopharyngeal tonsil, soft palate tonsil, and lingual tonsil became thicker, and lymphoid follicles in the lamina propria were clearly visible at the age of 21 days. Secondary lymphoid follicles were present in the nasopharyngeal tonsil at the age of 50 days, and in the soft palate tonsil at the age of 120 days. Dendritic cells (DCs), CD3⁺ T cells and IgA⁺ B cells in the soft palate tonsil, nasopharyngeal tonsil and lingual tonsil increased continuously, especially during the first 21 days. The results suggested that tonsils have an important role in local immune defense against invading antigens after birth and will be beneficial for understanding the mechanisms of immunity in these animals after nasal and oral vaccination.     

Organization of lymphoid tissue in the tonsilla lingualis

Summary Lymphoid organs are highly organized structures made up of different tissue compartments, each with its own specific cell populations. However, the cellular elements of the lingual tonsil, which forms a significant part of Waldeyer's pharyngeal ring, are not yet documented. This study, therefore, describes the fine structure and tissue organization of tonsilla lingualis in Macaca fascicularis. Ten selected crypto-lymphatic units originating from five perfusion-fixed animals were analysed ultrastructurally. Based on the fine-structural elements contained within, the lymphoid tissue of tonsillar units could be subdivided into follicular (germinal centre) and parafollicular areas. The latter contained predominantly small lymphocytes, lymphoblasts resembling T-blasts, plasma cells, macrophages, occasional neutrophils and many reticular cells resembling fibroblasts. A distinct feature of the parafollicular area was the presence of numerous high endothelial (HEV)or postcapillary venules (PCV). The follicular areas contained many small and large lymphoid cells, mitotic cells, plasmablasts, macrophages and specialised reticular cells resembling follicular dendritic cells (FDC) with distinct desmosomal junctions. These observations show that the crypto-lymphatic units of the lingual tonsil are, in fact, organised into distinct B- and T-cell compartments with their own specific lymphoid and accessory cells.     

Differential cytokeratin and glycoconjugate expression by the surface and crypt epithelia of human palatine tonsils

Human palatine tonsils are clinically important due to their susceptibility to tonsillitis and association with other local and systemic diseases. Paradoxically, the tonsils function as antigen sampling sites of the mucosal immune system and, consequently, the tonsil epithelia perform both protective and antigen sampling roles. These epithelia are divided into stratified squamous epithelium overlying the tonsil surface and crypt epithelium lining the tonsil crypts, the latter of which includes reticular areas which are infiltrated by lymphocytes and are responsible for antigen sampling. In this study we characterised cytokeratin and glycoconjugate expression by healthy epithelia of human palatine tonsils. We identified pan-epithelial tonsil markers and also demonstrated that the surface and reticular crypt epithelia are differentiated by the expression of multiple cytokeratins. The latter finding supports the hypothesis that these epithelia undergo alternate differentiation pathways and possess different functional roles. In addition, we identified cell subpopulations in the tonsil epithelia which may represent distinct cell subtypes including specialised antigen sampling cells. These findings establish a basis for future studies to investigate histochemical changes in tonsil epithelia that are associated with or predispose to local and/or systemic disease.     

Differentiation of the palatine tonsillar tissues of the human fetus]

Differentiation of epithelial and lymphoid tissues of the palatine tonsils was studied in human embryos at the age of 8-34 weeks of development by means of histochemical, immunomorphological and morphometric methods. The anlage of the palatine tonsils appears at the age of 9 weeks of fetal development. At the age of 13-14 weeks of fetal development the tonsil suspension contains 2 subpopulations of lymphocytes possessing properties of T-cells differing in the ability of their superficial receptors to interact with sheep erythrocyte antigens forming rosettes (RFC--rosette forming cells) and with antigens of their own erithrocytes (autoRFC). The number both increases sharply by the 16th week of gestation. Simultaneously, essential alterations are noted in epithelial and lymphoid tissues. In epithelium of crypts cornified cells appear; the amount of lymphoid tissue increases sharply, primary follicles without reactive centers appear, lymphocytic infiltration of epithelium occurs. The amount of RFC does not change considerably, and the amount of autoRFC has a tendency towards some increase. From the data obtained, it is possible to suggest that human palatine tonsils already at embryonic period participate in functioning of immunogenic organs and in maintaining of immunologic homeostasis of the fetal organism.     

Rabbit tonsil-associated M-cells express cytokeratin 20 and take up particulate antigen.

M-cells are believed to play a pivotal role in initiation of the immune response. These cells, located in the epithelia that overlie mucosal lymphoid follicles, are responsible for the active uptake of particulate antigens and for their translocation to the underlying lymphoid tissue. The identification of reliable markers for M-cells is therefore extremely important for the study of the initial steps that lead to the immune response. For this purpose, we studied cytokeratin 20 (CK20) expression in the epithelium of rabbit palatine tonsils by immunofluorescence, confocal microscopy, and Western blotting. CK20+ cells were observed in all rabbit palatine tonsils examined. By Western blotting, one CK20-immunoreactive band was identified at 46 kD on samples of proteins from the intermediate filament-enriched cytoskeletal fraction of tonsil epithelium. Double labeling of CK20+ cells with cell-specific markers confirmed that such cells were actually M-cells. Moreover, CK20+ M-cells displayed a mature phenotype (they formed pockets harboring lymphoid cells) and were functionally competent because they could take up particulate antigens from the pharyngeal lumen. We conclude that CK20 is an M-cell marker for rabbit palatine tonsils. Moreover, we can hypothesize the use of M-cells as a possible site for antigen delivery of particle-based vaccines.     

Bipedal locomotion in ratites (Paleognatiform): examples of cursorial birds

The gaits of five Ostriches Struthio camelus , seven Emus Dromaius novaehollandiae, two Greater Rheas Rhea americana, two Southern Cassowaries Casuarius casuarius and one Brown kiwi Apteryx australis were filmed at zoological parks. Locomotor parameters were measured using footprints on sandy tracks and video records. Osteological measurements were made on skeletons of the pelvic limbs. All of these terrestrial birds shift from wallking to running at a relative speed below 1. However, they show two different locomotor patterns: the Brown Kiwi increases its speed by increasing its stride length, mainly by increasing the protraction angle. Its hindlimbs make a flexed jointed chain system, its centre of mass is anterior, its femurs are long and the knees act in yield whereas the distal joints act in propulsion. Other ratites, particularly Ostriches, increase their speed by increasing frequency. Their centre of mass is close to the hip, their hindlimbs have an extended jointed chain system with a short erect femur, maximizing a gravity-powered system.     

Cathepsin E in follicle associated epithelium of intestine and tonsils: localization to M cells and possible role in antigen processing

A specific rabbit anti-human serum was used selectively to localize the aspartic proteinase cathepsin E to follicle associated epithelium (FAE) of human and rat intestine, including jejunum, ileum, appendix, colon and rectum, as well as of human palatine, pharyngeal and lingual tonsils. Coexpression of class II histocompatibility antigen HLA-DR antigen has been observed in some of the cathepsin E-positive epithelial cells. In addition, cathepsin E has been detected in a few mononuclear cells of intestinal lymphoid structures and tonsils resembling interdigitating reticulum cells of lymph nodes. Another aspartic proteinase, cathepsin D, has been found to be poorly represented in FAE and intensely expressed by macrophages. Electron immunocytochemistry localized cathepsin E to endosomal vesicles and endoplasmic reticulum of M cells in rat and human ileum as well as of M-like cells in human palatine tonsil. The results suggest a possible role of endosomal cathepsin E in the processing of macromolecules and microorganisms transported by M cells and related epithelial cells to mucosal associated lymphoid tissue (MALT).     

Age-related changes in the morphology and the distribution of IgA and IgG in the pharyngeal tonsils of yaks (Bos grunniens)

To evaluate age-related changes in the morphology as well as the expression and localization of IgA and IgG in yak pharyngeal tonsils, 20 healthy yaks were divided into four age groups [newborn (1–7 days old), juvenile (5–7 months old), adult (3–6 years old) and old (7–10 years old)]. Morphologic characteristics were observed by histological techniques. The expression and localization of IgA and IgG in pharyngeal tonsils were detected by enzyme linked immunosorbent assay (ELISA) and immunohistochemistry, respectively. The results showed that the epithelium of the pharyngeal tonsils included nonreticular epithelium with an intact basement membrane and reticular epithelium with a discontinuous basement membrane and nonepithelial cell infiltration. In newborn yaks, only primary lymphoid follicles were observed in pharyngeal tonsils. In other age groups, both primary and secondary lymphoid follicles were observed, but some of the lymphoid follicles in the old yaks were degenerated. The number of lymphoid follicles increased from the newborn to the adult group and peaked in the adult group, but the number decreased in the old group. In addition, the age-related trends of IgA and IgG protein expression were similar to those of the number of lymphoid follicles. The concentration of IgG was significantly higher than that of IgA in all age groups. Both IgA and IgG antibody secreting cells (ASCs) were distributed in the subepithelial region of the nonreticular epithelium, the reticular epithelium, the lymphoid follicles, the interfollicular areas and in between the salivary glands. The densities of IgA and IgG ASCs in pharyngeal tonsils were similar to the expression trend of both proteins in each age group. The results indicate that the morphology and amount of lymphoid follicles in yak pharyngeal tonsils vary with age. Pharyngeal tonsils produce more IgG than IgA, indicating that IgG could be significant component of mucosal immune responses in yaks.     

Expression and function of tight junctions in the crypt epithelium of human palatine tonsils.

The human palatine tonsils have surface and crypt stratified epithelium and may be initiated via the epithelium to mount immune responses to various presenting antigens. Here we investigated the expression and function of tight junctions in the epithelium of human palatine tonsils from patients with tonsillar hypertrophy or recurrent tonsillitis. Occludin, ZO-1, JAM-1, and claudin-1, -3, -4, -7, -8, and -14 mRNAs were detected in tonsillar hypertrophy. Occludin and claudin-14 were expressed in the uppermost layer of the tonsil surface epithelium, whereas ZO-1, JAM-1, and claudin-1, -4, and -7 were found throughout the epithelium. In the crypt epithelium, claudin-4 was preferentially expressed in the upper layers. In freeze-fracture replicas, short fragments of continuous tight junction strands were observed but never formed networks. In the crypt epithelium of recurrent tonsillitis, the tracer was leaked from the surface regions where occludin and claudin-4 disappeared. Occludin, ZO-1, JAM-1, and claudin-1, -3, -4, and -14, but not claudin-7, mRNAs were decreased in recurrent tonsillitis compared with those of tonsillar hypertrophy. These studies suggest unique expression of tight junctions in human palatine tonsillar epithelium, and the crypt epithelium may possess an epithelial barrier different from that of the surface epithelium.     

Age-related aspects of the anatomy and topography of the human tubal tonsil

The tubal tonsil (TT) has been investigated in 60 preparations of the auditory tube (right and left), obtained from 30 corpses of persons at various age, those died from traumas and having neither any pathological changes in their acoustic organs, nor chronic inflammatory diseases by the time of death. The TT is presented as a solid or interrupted lymphoid tissue plate, situating in the mucosal membrane in the area of the pharyngeal opening to some extent in the inferior, posterior and anterior walls of the auditory tube. In newborns the TT is presented as a diffuse lymphoid tissue, where lymphoid nodules begin to form. The greatest amount of the lymphoid nodules in the TT are revealed in the infantile age and this sign is kept during subsequent age periods, including the first period of mature age. During these age periods on the surface of the mucosal membrane in the area of the pharyngeal opening numerous small eminences are seen--tubercles, corresponding in their position to lymphoid nodules under them. Beginning from the second mature period and up to old age the amount and size of the lymphoid nodules in the TT decreases. At that time on the surface of the mucosal membranes in the area of TT only single tubercles are revealed.     

Membranous cells in nasal-associated lymphoid tissue: a portal of entry for the respiratory mucosal pathogen group A streptococcus

Human tonsils are suspected to be an antibiotic-impervious human reservoir for group A streptococcus. An intranasal infection model in mice and a bioluminescent-tagged strain were used to investigate this possibility. Viable streptococci were predominantly found both intra- and extracellularly in nasal-associated lymphoid tissue (NALT), a human tonsil homologue. Ulex europaeus-1, a membranous (M) cell-specific lectin, identified cells harboring streptococci at the epithelial surface of NALT and blocked bacterial colonization of this tissue. These results suggest that M cells in NALT transport this Gram-positive pathogen across the epithelial layers in a manner similar to those in Peyer's patches, which permit enteric pathogens to invade deeper tissues from the gastrointestinal tract.