bluuebunny/crossref_metadata_2025_split huggingface dataset:
Localization of lymphocyte subpopulations in peripheral lymphoid organs: Directed lymphocyte migration and segregation into specific microenvironments
Authors: Rouse Robert V. , Reichert Roger A. , Gallatin W. Michael , Weissman Irving L. , Butcher Eugene C. 
Published: February 2005

AbstractThe distribution of lymphocytes in the peripheral lymphoid organs is controlled by recirculatory and microenvironmental factors. Specific interactions between recirculating lymphocytes and high endothelial venules in various lymphoid sets and subsets in those organs. Separate endothelial determinants on peripheral node and Peyer's patch endothelium along with complementary lymphocyte receptors mediate this organ specificity. B and T cells also exhibit nonrandom organization within lymphoid tissues; after entry via high endothelial venules they segregate into their respective domains, which appear to be determined by distinct types of nonlymphoid stromal cells. Antigenic stimulation results in changes in lymphocyte phenotype as well as in the lymphoid microenvironment. The response to most complex antigens is the formation of germinal centers (GC) composed primarily of proliferating B cells; the phenotype of the few T cells therein is supportive of the GC as a site of B‐T interaction. The phenotype of the B cells in GCs suggest a role for GCs in immunoglobulin class switching and the determination of subsequent homing specificity.
Functional anatomy of germinal centers
Authors: Nieuwenhuis P. , Opstelten D. 
Published: February 2005

AbstractThis year we celebrate the first centennial of the discovery of germinal centers by Flemming in 1884. The present paper reviews and adds new data to the functional anatomy of a germinal center. Emphasizing its reactive nature, we first describe a germinal center reaction and then deal with its infrastructural aspects and constituent cell populations, both lymphoid and nonlymphoid. Elements involved in the de novo formation of a germinal center, like antigen, T cells, and the mysterious germinal‐center‐precursor cell, are discussed. Next, attention is paid to the requirements for lymphoid cells to migrate into germinal centers, and novel features of germinal‐center‐seeking cells are presented. Subsequently, we discuss kinetic aspects of the high proliferative activity in a germinal center; and finally a description of the functional capacities of germinal‐center‐derived cells, such as B memory cells and IgM‐antibody‐forming cell precursors, completes this picture of present‐day knowledge of the germinal center, a structure which has yet to reveal its last secrets.
Gut‐ and bronchus‐associated lymphoid tissue
Authors: Bienenstock John , Befus Dean 
Published: February 2005

AbstractBronchus‐associated and gut‐associated lymphoid tissues (BALT and GALT) have both functional and morphologic similarities and are involved in seeding lung, gut, and other mucosal sites with predominantly IgA‐containing B cells. Both types of lymphoid tissue are engaged in the regulation and the controlled amplification of immune responses, which vary from positive mucosal responses in both mucosae and peripheral tissues to local mucosal responses and systemic tolerance. Their further involvement in provision of cells destined to reside in the epithelial compartment of the body appears likely but requires further investigation. Their role in the provision of precursors of mucosal mast cells must also be explored further, but some participation in this event appears likely. The mucosa‐associated lymphoid tissue (MALT) system appears to be integrated with the systemic immune system but may be considered as separate from it in several functional ways.
The hematopoietic stroma
Authors: Weiss Leon , Sakai Hidetaka 
Published: February 2005

AbstractThe stroma of the hematopoietic tissues includes a number of diverse cell types, i.e., bone‐lining cells and related capsular and trabecular structures, epithelial‐reticular cells and other epithelial cells, reticular cells, macrophages, and antigen‐presenting cells. These stromal cells possess a variety of mechanical and metabolic functions. They support and confine the hematopoietic tissues and their vasculature. They regulate the migrations of blood and hematopoietic cells. Stromal cells contribute to the microenvironment that induces the differentiation of stem cells into the several blood‐cell lines. The nature of the interactions of stromal and hematopoietic cells depends upon long‐ and short‐range humoral factors, and upon such cell‐surface compounds as immunoglobulins and major histocompatability antigens. Blood cells themselves, as neutrophils and lymphocytes, play regulatory roles in hematopoiesis along with stromal cells. Moreover, certain stromal cells, such as macrophages, originate as blood cells and have migratory phases. Distinctions between blood cells, their derivatives, and stromal cells may therefore be difficult to draw.
The anatomy of peripheral lymphoid organs with emphasis on accessory cells: Light‐microscopic immunocytochemical studies of mouse spleen, lymph node, and peyer's patch
Authors: Witmer Margit D. , Steinman Ralph M. 
Published: February 2005

AbstractAntigen, lymphocytes, and accessory cells interact within peripheral lymphoid organs to generate immunity. Two cell types have been studied for accessory function in culture: mononuclear phagocytes and nonphagocytic Ia‐rich dendritic cells. The monoclonal antibodies which have been used to study isolated murine macrophages (MØ) and dendritic cells (DC) include α‐macrophage (F4/80, M1/70), α‐dendritic cell (33D1), α‐Fc receptor (2.4G2), and α‐Ia (B21‐2) reagents. In this paper, the antibodies have been used to stain accessory cells in cryostat sections of mouse spleen, lymph node, and Peyer's patch. Each organ is known to contain subregions that are rich in either macrophages, B cells, or T cells. We found that the accessory cells in each subregion had a different phenotype. (1) Macrophage‐rich regions: Macrophages that lined the site of antigen delivery (marginal zone of spleen, around afferent lymphatics of node, and below the epithelium of Peyer's patch) were stained with M1/70 but not with F4/80. F4/80 was abundant on macrophages in other sites: spleen red pulp, node medulla, and around Peyer's patch efferent lymphatics. (2) B‐lymphocyte‐rich follicles: Follicular dendritic cells, which retain immune complexes extracellularly, are concentrated on the outer aspect of the germinal center. This region stained strongly with α‐Fc receptor antibody 2.4G‐2, but not with M1/70, F4/80, or 33D1. (3) T areas: The interdigitating cells of T areas have been linked to isolated dendritic cells. Irregular Ia‐rich cells were distributed uniformly in the T areas of each organ. However, staining with 33D1 was not detected and was restricted to foci of nonphagocytic cells at the spleen red/white pulp junction. F4/80, M1/70 or 2.4G2 also did not stain the T area, except for the region close to splenic central arteries. Therefore the principal surface markers and location of the candidate accessory cells in murine lymphoid organs are M1/70+ macrophages at the site of antigen entry; F4/80+ macrophages around regions of lymphocyte efflux; germinal center dendritic cells, which may be rich in 2.4G2; and Ia‐rich interdigiting cells in the T area.
Antigen processing and presentation by macrophages
Authors: Allen Paul M. , Unanue Emil R. 
Published: February 2005

AbstractThe classical macrophage is one of the most important cells involved in presenting antigen to helper T cells, because of its ability to regulate its expression of Ia molecules and to encounter and process particulate and soluble antigens. We have summarized in this report studies examining the handling by macrophages of two different antigens, the bacteria Listeria monocytogenes and the protein hen egg white lysozyme (HEL). The purpose was to identify potential sources of immunogenic peptides. Presentation of Listeria required an intracellular processing stage sensitive to lysosomotropic drugs. The Listeria required internalization and processing, after which immunogenic molecules were recognized by T cells on the macrophage surface. Metabolic studies showed that Listeria‐derived peptides were released by macrophages that had phagocytosized the bacteria. The release of these peptides was a temperature‐dependent process, unaffected by inhibiting lysosomal catabolism by treatment with chloroquine. Listeria‐derived peptides were also detected on the surface of the macrophage. These peptides behaved like integral membrane proteins, some of which persisted for at least 24 hr at the macrophage surface. When tested for immunogenicity, the released peptides were very weakly immunogenic. The membrane‐associated peptides alone could not stimulate Listeria‐specific T cells, but could be reprocessed by additional macrophages and subsequently stimulate the T cells. A defined antigen system using HEL‐specific T‐cell hybridomas was used to examine the processing of HEL. Presentation of HEL required a choloroquine‐sensitive intracellular processing stage. In examining two T‐cell hybridomas, a differential requirement for antigen processing was determined. The immunogenicity of released HEL from HEL‐pulsed macrophages was also tested, and no “processed” antigen was detected capable of directly stimulating T cells; however, native HEL was released from the macrophage and could be processed and presented by other macrophages.
Cells of the fetomaternal interface: Their role in the maintenance of viviparous pregnancy
Authors: Lala P. K. , Kearns M. , Colavincenzo V. 
Published: February 2005

AbstractAn immune system capable of discriminating between self and nonself evolved in nature long before the appearance of the viviparous mode of pregnancy, which brings maternal cells into a direct physical contact with genetically disparate cells of fetal origin. In the hemochorial type of placentation, the former include cells of the maternal immune system. This article briefly reviews the possible mechanisms that may protect the semiallogeneic conceptus in nature, with special reference to the role of the cells at the fetomaternal interface. We also present some new data on the antigenicity of pre‐ and postimplantation trophoblast cells and the immunobiology of decidual cells. Systemic changes in the maternal immune system appear to represent homeostatic responses to the presence of a semiallogeneic conceptus, unrelated to its protection; mechanisms for this protection must reside locally at the fetomaternal interface. We find that the lack of immunogenicity of the outer (trophoblast) cells of the preimplantation blastocyst can be explained by a transient disappearance of the major histocompatibility (MHC) antigens on their cell surface. However, following implantation and the formation of the placenta, class 1 MHC antigens reappear on certain classes of trophoblast cells, i.e., labyrinthine and spongiotrophoblast cells of the murine placenta. Similarly, cytotrophoblast cells of the early human placenta exhibit the presence of class 1 MHC antigens. An absence of class 2 MHC antigens despite the presence of class 1 antigens cannot entirely explain the lack of trophoblast immunogenicity. A local immunosuppression mediated by trophoblast cells themselves as well as maternal cells of hemopoietic origin in the decidua remain as a strong possibility. Typical decidual cells appear to play a central role in the maintenance of pregnancy because of their numerous functions: nutritive, endocrine, and immunoregulatory. Our studies reveal that they are descendants of bone‐marrow‐derived precursors, have unique surface markers recognizable with monoclonal antibodies nonreactive with other hemopoietic cell lineages, and have the ability to abrogate mixed lymphocyte reactions in vitro in a genetically unrestricted manner. Further studies directed at the cells of the fetomaternal interface should provide a better insight into the mode of survival of the nature's most commonplace allograft.
Influence of colchicine and vinblastine on the intracellular migration of secretory and membrane glycoproteins: II. Inhibition of secretion of thyroglobulin in rat thyroid follicular cells as visualized by radioautography after 3H‐fucose injection
Authors: Wild G. , Bennett G. 
Published: February 2005

AbstractYoung (40 gm) rats were given a single intravenous injection of colchicine (4.0 mg) or vinblastine (2.0 mg). At 10 min after colchicine and 30 min after vinblastine administration, the rats were injected with 3H‐fucose. Control rats received 3H‐fucose only. All rats were sacrificed 90 min after 3H‐fucose injection and their tissues processed for radioautography.In thyroid follicular cells of control animals, at this time interval, 57% of the total label was associated with colloid and secretory vesicles in the apical cytoplasm while 27% was localized in the Golgi apparatus and neighboring vesicles. In experimental animals, the proportion of label in colloid and apical vesicles was reduced by more than 69% after colchicine and more than 83% after vinblastine treatment. The proportion of label in the Golgi region, on the other hand, increased by more than 125% after colchicine and more than 179% after vinblastine treatment. Within the Golgi region, the great majority of the label was associated with secretory vesicles which accumulated adjacent to the trans face of the Golgi stacks. It is concluded that the drugs do not interfere with passage of newly synthesized thyroglobulin from the Golgi saccules to nearby secretory vesicles, but do inhibit intracellular migration of these vesicles to the cell apex. In most cells the number of vesicles in the apical cytoplasm diminished, but this was not always the case, suggesting that exocytosis may also be partially inhibited. The loss of microtubules in drug‐treated cells suggests that the microtubules may be necessary for intracellular transport of thyroglobulin.
Influence of colchicine and vinblastine on the intracellular migration of secretory and membrane glycoproteins: III. Inhibition of intracellular migration of membrane glycoproteins in rat intestinal columnar cells and hepatocytes as visualized by light and electron‐microscope radioautography after 3h‐fucose injection
Authors: Bennett G. , Carlet E. , Wild G. , Parsons S. 
Published: February 2005

AbstractIn the first paper of this series (Bennett et al., 1984), lightmicroscope radioautographic studies showed that colchicine or vinblastine inhibited intracellular migration of glycoproteins out of the Golgi region in a variety of cell types. In the present work, the effects of these drugs on migration of membrane glycoproteins have been examined at the ultrastructural level in duodenal villous columnar cells and hepatocytes.Young (40 gm) rats were given a single intravenous injection of colchicine (4.0 mg) or vinblastine (2.0 mg). At 10 min after colchicine and 30 min after vinblastine administration, the rats were injected with 3H‐fucose. Control rats received 3H‐fucose only. All rats were sacrificed 90 min after 3H‐fucose injection and their tissues processed for radioautography.In duodenal villous columnar cells, 3H‐fucose labeling of the apical plasma membrane was reduced by 51% after colchicine and by 67% after vinblastine treatment; but there was little change in labeling of the lateral plasma membrane. Labeling of the Golgi apparatus increased. This suggests that labeled glycoproteins destined for the apical plasma membrane were inhibited from leaving the Golgi region, while migration to the lateral plasma membrane was not impaired. In hepatocytes, labeling of the sinusoidal plasma membrane was reduced by 83% after colchicine and by 85% after vinblastine treatment. Labeling of the lateral plasma membrane also decreased, although not so dramatically. Labeling of the Golgi apparatus and neighboring secretory vesicles increased. This indicates that the drugs inhibited migration of membrane glycoproteins from the Golgi region to the various portions of the plasma membrane. Accumulation of secretory vesicles at the sinusoidal front suggests that exocytosis may also have been partially inhibited. In both cell types, microtubules almost completely disappeared after drug treatment. Microtubules may, therefore, be necessary for intracellular transport of membrane glycoproteins, although the possibility of a direct action of these drugs on Golgi or plasma membranes must also be considered.
Ultrastructural and cytochemical observations on 5‐fluorouracil‐induced cleft‐palate development in hamster
Authors: Shah Ravindra M. , Wong David T. W. , Suen Roger S. K. 
Published: February 2005

AbstractSequential alterations in 5‐fluorouracil‐treated hamster fetal palate were studied by light and electron microscopy and by acid phosphatase cytochemistry. At an early stage in 5‐fluorouracil‐treated fetuses, when the palatal shelves were vertical, lysosomes first appeared in cells of the prospective fusion epithelium and then in the cells of subjacent mesenchyme. In contrast to controls, increasing numbers of both the epithelial and mesenchymal cells of the vertical palate showed lysosomal injury in 5‐fluorouracil‐treated fetuses as development progressed. Subsequently, the basal lamina in the vertical palate showed alterations, characterized initially by disturbances in lamina lucida, by fingerlike extensions of lamina densa, and ultimately by its complete breakdown. At a later stage, when shelves became horizontal, the lysosomes were absent in both the epithelial and mesenchymal cells, and the basal lamina continuity was restored. Unlike controls, however, 5‐fluorouracil‐treated horizontal shelves never contacted one another. Instead, the epithelia of the horizontal shelves underwent stratification. It appears that premature formation of lysosomes in palatal epithelial and mesenchymal cells following 5‐fluorouracil treatment disrupts normal cytodifferentiation and affects the integrity of the basal lamina; both effects are associated with cleft‐palate development.
The nasopalatine ducts and associated structures in the rhesus monkey (Macaca mulatta): Topography, prenatal development, function, and phylogeny
Authors: Zingeser Maurice R. 
Published: February 2005

AbstractMorphological and developmental characteristics of the rhesus monkey nasopalatine duct system and associated primary palatal structures are described along with functional and phylogenetic considerations. Examination of five adult palates and coronal sections of 13 fetal palates together with dissections of a sixth adult specimen and of a 119‐day‐old fetal palate reveal that the lateral lobes of the tripartate incisive papilla cover clefts leading into the ducts. The ducts pierce the bony palate to enter the nasal fossae in proximity to the incisive suture. The ontogenetic stability of the duct path reflects the retention of ancient duct and primitive choanae relationships and functionally maintains an optimal oral odorant‐to‐receptor channel.Sixteen timed pregnancy specimens (35–100 days) provided histological material for documenting rostral nasopalatal development. Duct primordia, identified at 35 days, had by 40 days formed the medial duct walls (conjoined septum‐papilla from the primary medial palatal component), the lateral duct walls (maxillary processes), and the rostral walls (fused maxillary‐intermaxillary components). The caudal walls derive from the fusion of palatal shelves with the papilla (45 days), thus distinguishing primary and secondary fusion modes. Duct epithelial maturation occurs between 70 and 100 days.The absence of a vomeronasal system is attributed to reduction of olfaction in reproductive behavior, while the presence of the coevolved nasopalatine ducts is linked to the persistence of epiglottal‐velar valving. The ducts serve as oral food‐odor conduits in otherwise functionally separated respiratory and digestive tracts.
Cellular composition and organization of ductal buds in developing rat mammary glands: Evidence for morphological intermediates between epithelial and myoepithelial cells
Authors: Ormerod E. Jane , Rudland Philip S. 
Published: February 2005

AbstractIn the developing rat mammary gland, terminal end buds (TEBs), lateral buds and alveolar buds represent the major sites of morphogenetic activity and cellular differentiation. The morphology and cellular composition of these buds from 20‐to 22‐day‐old rats and cycling rats have been studied by immunocytochemical and electron microscopic techniques. The mammary buds are composed of a heterogeneous collection of cells including epithelial and myoepithelial cells, irregular loosely adherent cells, and occasional large clear cells. The irregular, loosely packed cells or cap cells are mainly situated around the periphery of the TEBs and lateral buds. “Chains” of irregularly shaped cells also extend from the peripheral cap cell layer to the center of the TEB; and, where they converge on lumina, they display microvilli and junctional complexes. At the tips of the end buds, the cap cells are of undifferentiated appearance; however, similar cells situated toward the subtending mammary ducts show a gradation in ultrastructure to that of myoepithelial cells. This change is accompanied by an increase in the amounts of immunoreactive myosin and keratin seen within the cells and a 200‐fold increase in the thickness of the basement membrane. In contrast, the peripheral cells of the alveolar buds are more closely packed, contain a greater number of myofilaments, and show increased staining with antisera to myosin. We suggest that the undifferentiated cap cells do not represent a discrete cell type, since they show transitional forms to myoepithelial cells within the subtending mammary ducts, and that the tendency toward the myoepithelial phenotype is predominant in the more differentiated structures, the alveolar buds.
Changes in the fine structure of rat visceral yolk‐sac placenta during prolonged pregnancy
Authors: Jollie William P. 
Published: February 2005

AbstractVisceral yolk‐sac membranes were obtained surgically from viable rat fetuses which had been retained experimentally in utero in lactating animals for as long as 3 days beyond delivery of their littermates. They were examined with the electron microscope. The fine structure of the yolk‐sac placental membrane (i.e., the tissues separating vitelline capillary lumina from the uterine cavity) remained unimpaired during the delay period. Progressive changes included a decrease in the height of the endodermal epithelium, but a thickening of the basement membrane underlying it by repeated replication of the subepithelial basal lamina and an increase in collagen fiber content in the reticular lamina. Transcytosis across the endothelium of the capillaries of the peripheral vitelline circulation remained unchanged throughout the delay period; endocytosis of materials, presumably maternal serum proteins, from the uterine cavity into the apices of the endodermal epithelium, however, decreased with time. At the oldest stage (26 days post‐coitum) most endocytosed materials had been stored for hydrolysis in large subapical vacuoles which were identified as secondary lysosomes; and evidence of uptake from the uterine lumen was essentially absent. Accordingly, placental transport of protein by the visceral yolk sac of the rat can be regarded as a perinatal process. The action of an elaborately developed and well‐preserved Golgi apparatus in both cellular mechanisms, viz., digestion of maternal proteins and protein transfer, was inferred.