Regional features of the cellular composition of different zones of lymph nodes in the adult human

The amount of plasma cells is connected with intensity of humoral immunological reactions. In people died an accidental death, the amount of immature plasma cells is the least in the axillary and the greatest--in the mesenteric nodes, especially in the thymus-independent zone. The amount of lymphoblasts and large lymphocytes, reflecting intensity of the humoral and cellular immune reactions, is also the greatest in the mesenteric lymph nodes, both in the thymus-dependent and in the thymus-independent zone. In all probability, the intensity of the immunological processes is minimal in the axillary, it is middle in the iliac and cervical and it is maximal in the mesenteric lymph nodes. In each case it is probably connected with peculiarities of antigenic composition of the lymph inflow. The mesenteric lymph nodes are on the way of the foreign protein getting into the intestine. This is evidently reflected by the highest content of immature plasma cells, lymphoblasts and large lymphocytes in them.     

Changes in the iliac lymph node of the rat in aseptic uterine inflammation and during its correction]

In the lymphoid tissue of the iliac lymph node at an aseptic inflammation in the uterus the greatest changes have been revealed in 48 h from the moment, when the foreign body has been introduced. They are manifested at the tissue level (increasing content of macrophages, lymphoblasts, large lymphocytes, plasmoblasts, immature plasmocytes, mast cells, neutrophils), as well as at the organic level (increasing amount of secondary lymph noduli, increasing area of the paracortical zone, decreasing area of the cortical plateau, of the medullary intermediate sinus, medullary cords). Use of carbomineral sorbents ensures correction of the inflammation; this is demonstrated as reduction of reactive changes in the regional lymph node.     

Functional morphology of the lymphatic system of the rat uterus during pregnancy

In the regional lymph nodes of the uterus the comparative volume of the paracortical zone significantly increases, especially within the period of the 13th-17th days of pregnancy. In the popliteal lymph node similar effect is not discovered. From the 7th up to the 11th day edema, vasodilatation, infiltration with special leucocytes are revealed. Endothelium of the postcapillary venules is hypertrophied, contains many migrating lymphocytes, which accumulate around the vessels mentioned. The volume of the microcirculatory bed is moderately increased. By the 17th day plasmoblasts, plasmocytes, Motta's cells, monocytes and especially macrophages appear in the paracortical zone. In B-zones and in medullary sinuses blasts, plasma cells, monocytes, macrophages, mitotically deviding cells increase in number. The part of the reticular cells decreases. The tensometric method demonstrates an increasing pressure of lymph in the iliac lymph node at pregnancy. Collateralies appear in the ovarian vein system, in the broad ligament of the uterus, in the lumbar area. The uterine vascular system is supposed to participate in adaptation to pregnancy. In genesis of the regional lymph node changes, discirculatory shifts, predominating during placental organogenesis, combine with phenomena of cell migration and proliferation (clearly revealed by the time when formation of the placenta is completed).     

Morpho-functional changes in the lymph nodes during fever reaction]

Lymph nodes (mesenteric, popliteal, cervical) of rabbits in fever reaction of different duration have been studied in our work. As a whole morpho-functional changes in lymph nodes in fever reaction indicate the increase of their functional activity: hyperplasia of lymphatic substance with the growth of lymphocytes number and slightly differentiated lymphoid cells in follicles and paracortical zone, hyperplasia of pulposus bands, the signs of macrophagal reaction and plasmatization of lymph nodes are to be observed and all these create prerequisites for the increase of tensity of cellular and humoral immunity. Simultaneously the signs of destruction of cellular elements--lymphocytolysis in the porta tract and the growth of number of PAS-positive cells in the parenchyma of the nodes take place.     

Structural changes in popliteal lymph nodes in the graft vs. host reaction to H-Y antigen in male C57BL/6-strain mice

Regional popliteal lymph nodes in intact, control and experimental (I, II, III groups, respectively) have been studied by means of the morphometric method in male C57Bl/6 line mice at the pick of the reaction produced by injection of spleen cells and mesenteric lymph nodes obtained from syngenic females and repeatedly immunized to H-Y antigen (10 animals in each group). Injection of the cell suspensions from the immunized and intact females of the C57Bl/6 mice result nearly in two-fold increasing mass of the regional popliteal node at the expense of enlarged size of all its zones. Changes in cytoarchitectonics of the node structural components result from redistribution of certain cellular elements. The essential changes in the cell composition of the lymph nodes in the II and III male groups are accompanied with an increasing part of the stromal reticular cells. Simultaneously, content of small lymphocytes decreases significantly. In the III group of mice there is a sharp increase in the content of young forms of the lymphoid line cells in all structural components of the node, as well as in eosinophilic granulocytes in medullary cords. In the dark cortical zone of the nodes (III group) there occur tissue basophils (mast cells), that, together with increasing number of acidophilic granulocytes and appearance of neutrophilic cells, demonstrates that there is an inflammatory reaction in the organ studied as a response to the lymphocytic suspension injected. In the experimental group of the animals a complete disappearance of plasma cells is noted in the node cortex, but some increase of their part takes place in the medullary cords.     

Structure of the arterial bed in human lymph nodes

Blood vessels, that bring blood to various areas of the human superficial inguinal lymph nodes are predominantly arterioles and precapillaries. They are often arranged radially from the hilus to the capsule and from the capsule towards the portal thickening. The arteries and arterioles of the portal and capsular trabeculae reach the paracortical zone, occupying an intermediate position between the medullary cords and the cortex of the lymph node. The arterioles of the paracortical zone, passing between the cortex and the medullary cords, acquire an arcuate appearance. In both directions from them (into central and peripheral areas of the node) precapillaries branch off at a right angle. The cortex is supplied with blood by the arteriolar branches of the paracortical zone and the capsule of the node. The cortical precapillaries branch into capillaries either within the lymphoid nodules, or along their periphery. In the medullary cords those arterioles branch, that get from the portal thickening, portal trabeculae and paracortical zone.     

A study of lymphocyte subsets in human normal tonsil and lymph node

A series of T and B lymphocyte specific monoclonal antibodies was used to determine the localization of lymphocyte subpopulation in frozen and paraffin tissue sections of human normal tonsil and lymph node by means of immunocytochemical technique. In the paracortical and interfollicular area of tonsil and lymph node, most lymphocytes reacted with Leu 1, Leu 3 a, Leu 4 and OKT4. The numbers of Leu 2 a and OKT8 positive cells were rare in tissue. These cells were not only limited in paracortical area, they also appeared in considerable numbers in medullary cords of lymph nodes. Leu 2 a and OKT 8 positive cells decreased with prominent follicular hyperplasia of tonsils. In addition, substantial leu 3 a and Leu 4 cells were found in the germinal centers. This finding supports the importance of these lymphocyte subsets in regulation of human immune response. In the mantle zone of secondary follicles, the majority of lymphocytes were positive for OKB 2 and BA 1, whereas, the IgM positive cells were predominately observed in the cytoplasma and extracellular substance of B lymphocytes in the germinal centers, but the lymphocytes bearing sIgM were rarely observed. In the mantle zone, the IgM were frequently found on the surface of membrane of small lymphocytes, however, the staining intensity was much than that in the germinal centers.     

Structure of the thymus, iliac and mesenteric lymph nodes in the rat at different stages of pregnancy

Development of pregnancy results in a systemic reaction of the immunogenetic organs: the structure of both the central (thymus) and peripheral lymphoid organs (lymph nodes) undergoes certain changes, beginning from its earliest stages (preimplantation period). Unidirection of the processes in the iliac (that are regional for the uterus) and mesenteric lymph nodes is stated. The reconstruction of the node occurs according to the reaction type at tissue allotransplantation, when hypertrophy of the thymus-dependent zone comes forward. During the period of the greatest manifestations of these alterations, however (the second half of pregnancy) the migration process of lymphocytes from blood into the lymph node is significantly inhibited. This is essentially clear in the iliac lymph nodes. The reconstruction of the thymus is in general similar with phenomena of accidental involution. However, accumulation of thymocytes in the medulla demonstrates blocking of their discharge into the blood stream. The disturbed processes of recirculation of result in incompleteness of the immune response at pregnancy and, perhaps, are included into the protective mechanisms of the offspring reproduction.     

High endothelial venules of the lymph nodes express Fas ligand.

Fas (CD95, APO-1) is widely expressed on lymphatic cells, and by interacting with its natural ligand (Fas-L), Fas induces apoptosis through a complex caspase cascade. In this study we sought to survey Fas-L expression in vascular and sinusoidal structures of human reactive lymph nodes. Immunohistochemical Fas-L expression was present in all paracortical high endothelial venules (HEVs), in cells lining the marginal sinus wall, and in a few lymphocytes, but only occasionally in non-HEV vascular endothelium. In the paracortical zone over 60% of all vessels and all paracortical HEVs showed Fas-L expression, whereas in the medullary zone less than 10% of the blood vessels were stained with Fas-L. Normal vessels outside lymph nodes mostly showed no Fas-L expression. We show that in human reactive lymph nodes Fas-L expression is predominantly present in HEVs. Because the circulating lymphocytes gain entry to nodal parenchyma by transendothelial migration through HEVs, the suggested physiological importance of Fas-L expression in these vessels lies in the regulation of lymphocyte access to lymph node parenchyma by possibly inducing Fas/Fas-L mediated apoptosis of activated Fas-expressing lymphoid cells. The Fas-L expressing cells in the marginal sinus might have a similar function for cells accessing the node in afferent lymph.     

Degree of chromatin activity and the RNA level in lymphocytes of popliteal lymph nodes of dogs after administration of an antigen]

In the experiment performed on 127 dogs by means of cytospectrofluorometric analysis, using fluorochrome acridine orange in dynamics up to 1 year, changes in the level of chromatin activation and RNA content have been studied in lymphocytes of the germinative centers and the crown of lymphoid nodules, in the paracortical zone and medullary cords of the regional and contralateral popliteal lymph nodes, after subcutaneous injection of antigen (BCG vaccine, 0.2 mg/kg) into the lateral area of the foot of the left pelvic extremity. The immune response is accompanied with a periodical increase in the level of chromatin activation and RNA content in populations of lymphocytes in the regional and contralateral popliteal lymph nodes with maximum in 6 h, 3-7 days, 1-3 months after the antigen injection. The intensity of these processes has an unequal level in lymphoid cells of various structural components; it is higher in lymphocytes of the contralateral lymph node.     

Microanatomical organization and cytoarchitectonics of lymphoid tissue in the mesenteric lymph nodes under conditions of experimental total hyperthermia

Microanatomical organization and cell composition of the rat mesenteric lymph nodes have been studied under conditions of experimental total hyperthermia. Possibilities of the compensatory-adaptive reactions of the lymphoid tissue have been determined. Disturbances of microhemo-++- and lymphocirculation in the lymph nodes in different time after hyperthermia are accompanied with accumulation of mast cells and eosinophils in various zones of the node; they normalize certain physiological parameters of microcirculation and permeability of the metabolic microvessel walls. In 30 days after a single total overheating of the rat organism, the microanatomical organization changes in the lymph nodes investigated are manifested as atrophy of B-dependent zones and further volumetric increase of the paracortical zone. Therefore, it is possible to think about a decreasing intensity of the humoral immunity and increasing intensity of the cellular one.     

Morphocytochemical reaction of the lymph nodes in dogs to the administration of lysozyme

By means of morphological, morphometrical and histochemical methods pelvic and tracheobronchial lymph nodes have been studied in dogs and concentration of lysozyme has been estimated in blood serum, in lymph and the lymph nodes after a single intramuscular injection of lysozyme (2 mg/kg of body mass). In the material investigated total concentration of lysozyme reaches its maximal values in 6 h after injection, then it gradually decreases and in 48 h reaches its control level. Morphometrically changes in cell composition are revealed predominantly of immune-competent cells in T- and B-dependent zones of the lymph nodes. Thus, the volumetric part of lymphoblasts in the germinative centers of the lymphoid nodules reaches its maximal indices by 48 h after lysozyme injection, while plasmatization of the paracortical zone and of medullary cords increases up to the 7th day. By the 14th day the volumetric part of lymphoblasts, immunoblasts and plasmocytes decreases gradually, and in 21 days after injection of the drug contents of the blast forms of the cells in the structural-functional zones of the lymph nodes does not differ from that in the control. The data obtained demonstrate the immunomorphological rearrangement of the lymph nodes in response to the exogenic lysozyme administration.     

Cytoarchitectonics of ileocecal lymph nodes in newborn and sexually mature simians (pavian hamadrils)]

Cell composition of various components (cortical plateau, folliculi and cords) of ileocecal lymph nodes was studied in newborn, 1.5 and 2.5 months of age (2 animals) and in mature (3 animals) monkeys, Papio hamadryas. In histological sections obtained at the level of hilus of the lymph node cellular elements were counted by means of morphometric grid of Glagolev modifoed by S. B. Stefanov. The data obtained were statistically treated. Newborn and mature monkeys have their peculiar cytological profile in every structural component of the lymph node. The lymph nodes in the newborns contain much more reticular cells and young cellular forms (blast forms and large lymphocytes) than mature animals. In the newborns, the number of mitotically deviding cells in the cortical plateau and in folliculi is 6 times and in myelin cords 10 times as great as in mature monkeys. A much greater per cent of plasmatic cells in mature animals suggests their greater immunological activity. Age differences in cell composition of lymph nodes in young and mature monkeys seem to be connected with accumulation of cellular mass and growth of the node in young animals, as well as with general rearrangement of the organism as a whole (in particular with changes in nutrition, intensity of movement, hormonal background).     

Characteristics of the cellular reactions of the T- and B-dependent areas of the regional lymph nodes in dogs to the administration of immunodepressants

Mesenteric, bifurcational, axillary and popliteal lymph nodes have been studied in 22 healthy mature male dogs. Amount of blast cells, small lymphocytes, plasma cells and macrophages has been taken into account in the paracortical zone, in the germinative centers and in the medullary cords. For two weeks to one group of the animals every day imuran in turn with aurantin (10 mg/kg and 25 mg/kg) are injected, or antilymphocytic serum (ALS) intraperitoneally every other day (0.1 ml/kg). The combined injection of imuran and aurantin produces a more pronounced toxic effect to the hemopoietic organs than ALS. ALS is more specific for T-dependent zones of the lymph nodes. In the dose and interval mentioned ALS is an immunostimulating preparation for the immunocompetent cells of the germinative centers of the lymph nodes. The reaction of the lymph nodes depends on their regional belonging.     

降钙素基因相关肽(CGRP)mRNA在大鼠淋巴细胞中的表达

最近,我们研究发现大鼠胸腺和淋巴结淋巴细胞中存在降钙素基因相关肽（ＣＧＲＰ）样免疫反应活性。应用人工合成的可特异扩增降钙素／降钙素基因相关肽基因部分片断的寡核苷酸引物,通过逆转录－多聚酶链反应（ＲＴ－ＰＣＲ）,检测在大鼠脊髓背根神经节、胸腺细胞及肠系膜淋巴结淋巴细胞中是否存在ＣＧＲＰ ｍＲＮＡ,进一步研究大鼠淋巴细胞能否合成ＣＧＲＰ。结果显示,通过ＲＴ－ＰＣＲ从脊髓背根神经节（阳性对照）、胸腺和淋     

Comparison of local and systemic responsiveness of lymphocytes in vitro to Bovicola ovis antigen and Concanavalin A in B. ovis-infested and naive lambs

The in vitro proliferation assay was used to determine lymphocyte responsiveness to soluble antigen of B. ovis and to Concanavalin A (Con A) in peripheral blood, spleen and various lymph nodes from B. ovis-infested and naive lambs. From March to July, an assay of monthly blood samples showed generally higher proliferative responses to antigen and Con A in B. ovis-infested than naive lambs. The proliferative response of cells from the skin-draining prescapular lymph nodes to B. ovis antigen was significantly higher in B. ovis-infested than naive lambs. Responses of cells from the medial iliac, mediastinal and mesenteric lymph nodes (which do not receive lymph from the skin) and spleen showed no significant differences between groups. Within the B. ovis-infested lambs, the response of cells from the prescapular lymph node was significantly higher than that from any other lymphoid organ examined. Responsiveness of the prescapular, medial iliac and mesenteric lymph node and spleen cells to Con A was not significantly different between groups, while mediastinal lymph node cells showed a significantly higher response in B. ovis-infested lambs. The data indicate that the antigen-specific cellular immune response is operating mainly locally, at the level of the skin and draining lymph nodes. Responses to the T cell mitogen Con A did not support non-specific immunodepression as reported in other ectoparasite/host systems.     

Changes in the cell population of the thymus-dependent area of the regional lymph nodes following skin flap grafting

In the paracortical zone of the regional lymph node changes in the cell population density of small and middle lymphocytes, immunoblasts, immature and mature plasma cells are taken into consideration. The observations are carried out for 954 h after transplantation. As demonstrates the analysis of the process segmentation, certain stages of the changes are revealed with duration of 150-160 h; that corresponds to circadian (circaseptan) range of biological rhythms. The duration of the first stage makes about a half of the circaseptan period. In quantitative changes of every cell type a slow trend and a periodical component are present. It is possible to suppose that during the first 3-4 days mobilization of cell resources takes place, further up to 13-16 days active reactions occur, directed to exfoliation of allogenic tissue components, and then after the exfoliation of the graft the amount of the cells becomes stable, however, rhythmical fluctuations are preserved. The reaction of the cell composition in the paracortical zone of the lymph nodes is in concord with the dynamics of changes in the cell population and in the transplant itself.     

Fibroblast-type reticular stromal cells regulate the lymph node vasculature

The lymph node vasculature is essential to immune function, but mechanisms regulating lymph node vascular maintenance and growth are not well understood. Vascular endothelial growth factor (VEGF) is an important mediator of lymph node endothelial cell proliferation in stimulated lymph nodes. It is expressed basally in lymph nodes and up-regulated upon lymph node stimulation, but the identity of VEGF-expressing cells in lymph nodes is not known. We show that, at homeostasis, fibroblast-type reticular stromal cells (FRC) in the T zone and medullary cords are the principal VEGF-expressing cells in lymph nodes and that VEGF plays a role in maintaining endothelial cell proliferation, although peripheral node addressin (PNAd)(+) endothelial cells are less sensitive than PNAd(-) endothelial cells to VEGF blockade. Lymphotoxin beta receptor (LTbetaR) blockade reduces homeostatic VEGF levels and endothelial cell proliferation, and LTbetaR stimulation of murine fibroblast-type cells up-regulates VEGF expression, suggesting that LTbetaR signals on FRC regulate lymph node VEGF levels and, thereby, lymph node endothelial cell proliferation. At the initiation of immune responses, FRC remain the principal VEGF mRNA-expressing cells in lymph nodes, suggesting that FRC may play an important role in regulating vascular growth in stimulated nodes. In stimulated nodes, VEGF regulates the proliferation and expansion of both PNAd(+) and PNAd(-) endothelial cells. Taken together, these data suggest a role for FRC as paracrine regulators of lymph node endothelial cells and suggest that modulation of FRC VEGF expression may be a means to regulate lymph node vascularity and, potentially, immune function.     

Structure of the mesenteric lymph nodes in fetuses and offspring of white rats under the effect of indomethacin on the mother-fetus system

Mesenteric lymph nodes in fetuses and offspring of white rats have been studied during various age periods after indomethacin injection in doses 2.5 mg/kg and 1 mg/kg daily from the 18th up to 21st day of pregnancy. Dose-dependent retardation in formation of main structures of the mesenteric lymph nodes, decreasing amount of the lymphoid type cells have been revealed. Retardation in the capsule, sinuses and reticular fibers of the node takes place, as well as decrease in lympho- and plasmocytopoiesis. It is more pronounced after indomethacin in dose 2.5 mg/kg. Simultaneously, formation of the cerebral substance and appearance of lymphoid nodules and their germinative centers are delayed. After the drug effect (2.5 mg/kg), up to the age of 2 weeks the amount of tissue basophils and eosinophilic granulocytes decreases. When the dose of the drug is 1 mg/kg decreasing amount of these cells is substituted for their compensatory increase on the 2d-3d week. The data obtained demonstrate a decreasing function of the lymph nodes, that depends on the dose of indomethacin.     

Entamoeba histolytica: lymphoreticular changes in gerbils (Meriones unguiculatus) with experimentally induced cecal amebiasis

Antibody responses and changes in the lymphoreticular tissues of gerbils with experimental cecal amebiasis were studied from 5 to 60 days PI. Changes in the cecum consisted of lymphoid follicle hyperplasia and depletion of lymphocytes, followed by follicle atrophy and histiocytosis. Mesenteric lymphadenopathy, and histologic alterations in the lymph nodes paralleled the progressive development of amebic cecal lesions. Early in the infection (5 to 10 days PI) mesenteric lymph nodes showed cortical follicle hyperplasia, blastogenesis in the paracortical areas (PCA) and intense lymphoblast and plasma cell activity in the medullary cords. At 20 to 30 days PI, the cortical follicles, the PCA and the medulla were depleted of lymphocytes and there was histiocytosis throughout the organ. At 60 days PI, lymphocyte repopulation took place in the PCA, and cortical follicles had active germinal centers. Spleen follicles did not increase in number as the infection progressed, but became hyperplastic. Antibody titers to ameba were low throughout the cecal infection but rose whenever amebic metastasis to the liver occurred. The results of this study indicate that lymphocytes from the submucosal lymphoid follicles and the draining lymph nodes may control the pathogenesis of the infection. Lymphoreticular tissue alterations could result from antigenic stimulation and migration of cells to the sites of infection.