Spatial-temporal organization of the deep cortex of the lymph node

In various areas of the deep cortex: central and peripheral parts, as well as T-territory (adjoining the fundus of the germinative center) various cells (small and middle lymphocytes, immunoblasts, plasmoblasts, immature and mature plasma cells and mitotically dividing cells) have been counted. The population density of various immunocompetent cells differs significantly in various areas of the deep cortex. Immunoblasts predominate in the center, cells of the plasmic line--in the periphery of the deep cortex and in the T-territory. Fluctuations of the population density are time-dependent. Spectral composition and parameters of rhythmicity for each cellular type and general course of the process are estimated. In the spectral composition ultradian components predominate. The circadian components are more specific for T- than for B-dependent zone. For immunoblasts in all the zones a common period of fluctuations, nearly 10 h, is revealed, and for the cells of the plasmic line 7 hours' period is common; therefore, it is possible to suppose presence of synchronizing pace-makers of the rhythm for T-lymphocytes, on the one hand, and for antibody-forming cells, on the other hand. Spectral composition of rhythmicity of the cells in the T-territory and in other part of the deep cortex has a number of similar components, that demonstrates functional unity of these zones. A higher part of the cells of the plasmic line in the T-territory and in the periphery of the deep cortex is, perhaps, connected with their migration along these areas towards medullar cords. The general process is of a complex character, rises and drops are registered at various time of the day.     

The effect of trauma on the structural-temporal organization of the T-dependent zone of a regional lymph node]

Experiments in 238 white mice have shown that after trauma there was a change in the population density (PD) of immune competent cells in the T-dependent zone of the regional lymph node (LN) both in the center of the deep cortex and in the T-territory adjacent to the germinative center. PD of small lymphocytes increases on the 1st-3rd days after trauma and returns to the initial level by the 4th-5th day. PD of mitotically dividing cells, immunoblasts, plasmablasts, immature and mature plasmocytes dramatically decreased on the 3rd day while an inconsiderable elevation of their PD took place on the 1st day in T-territory. The increased PD of small lymphocytes in the regional LN seems to be associated with their intensified release from the injury focus. The suppressed proliferation and differentiation of the plasmocyte line cells is the reaction to operation stress: in the posttraumatic period the spectral composition of fluctuations of PD of cells and parameters of its rhythmical components (both in the center of the deep cortex and in T-territory) were changed. As a rule, there was a displacement of acrophase and lessening of the rhythm amplitude. The general potency of the process after trauma increased. The amount of circadian components in the spectral composition of rhythmicity and their potency increased which speaks of central hormonal influences becoming greater.     

Morpho-functional status of the lymph nodes of rats during rehabilitation after exposure to vapors of dimethyl sulfate]

By means of histological methods inferior tracheobronchial lymph nodes have been investigated in 48 Wistar rats in 2 weeks and 3 months after cessation of inhalation of DNSV at maximum possible dose (0.1 mg/m3) for 2 and 14 days. Cell composition of the lymph nodes and cross sections of structural components have been compared. The cross section of the cortex decreases, while that of the medulla increases in comparison with corresponding parameters of the acute experiment. In 2 weeks and 3 months after DMSV effect for 2 days the part (%) of poorly differentiated cells and middle lymphocytes increases, while content of plasma cells in the medullary cords decreases. During rehabilitation after DMSV effect for 14 days a low level plateau is noted (as in the acute experiment). However, in lymphoid nodules++ within content of the poorly differentiated cells and middle lymphocytes in the cortical germinative centers in 2 weeks and 3 months the number of the poorly differentiated and reticular cells increases essentially, as well as mitotically dividing cells (in comparison to the acute experiment). In the medullary cords of the lymph nodes after 3 months of rehabilitation content of immature plasma cells is essentially higher than in 2 weeks of rehabilitation and than in the acute experiment. During rehabilitation the level of cells destruction in the lymph nodes noticeably decreases in comparison to the acute experiment.     

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.     

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.     

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.     

The reaction of somatic lymph nodes to experimental exposure to sulfide baths]

Influence of strong sulfide baths of the sanatorium "Talgi" to the popliteal and superficial inguinal lymph nodes (LN) has been studied in 35 rats (140-150 g of body mass) and 15 animals have been used as the control. The slices are stained with hematoxyli-eosin, after van Gieson, Romanovsky-Giemsa, Kurnik and silver nitrate impregnation after Foot. The section area of the LN decreases, but amount of lymphoid nodules increases (especially in deep layers of the cortex). In the germinative centers amount of middle lymphocytes and mitoses becomes larger. In the internodular zones of the popliteal nodes amount of macrophages and eosinophiles enlarges significantly, and in the inguinal-amount of mast cells and eosinophiles. In the medullary sinuses amount of macrophages declines. In the medullary cords amount of immature plasma cells and blasts increases, while amount of mature cells decreases.     

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.     

Effect of trauma on space-time organization of B-dependent area of the regional lymph node cortex

In the experiment performed on 238 non-inbred white mice it has been demonstrated that after trauma in the concha auricularis population density (PD) of immune-competent cells in the germinative center (GC) and in the crown of the regional lymph node (LN) changes. The PD of small lymphocytes increases, and the PD of mitotically dividing cells, immunoblasts, plasmoblasts, immature and mature plasmocytes decreases sharply in both zones. The increase of small lymphocytes PD in the regional LN after the trauma is obviously connected with intensification of their inflow from the lesion focus. Inhibition of proliferation and differentiation of the immune-competent cells in the GC of the crown is a response to the operation stress. During the posttraumatic period both spectral composition and parameters of the constituents of rhythmical alteration of the cells PD change both in the GC and in the crown. As a rule, displacement of acrophase and decrease in amplitude of the rhythm take place. Total power of the process for various types of immune-competent cells alters unequally. In the spectral composition of the rhythmicity amount of circadian components increases, their power increases, too. This demonstrates an increase of central hormonal effects during the posttraumatic period. After trauma fluctuations of the cells PD of the plasmacytic line, as well as in mitotically dividing cells with a 7-hour's period, which has been revealed in intact animals before the trauma, are preserved. This demonstrates a relative independence of the given synchronizer of rhythmicity at a tissue level from any influence of the higher regulatory center.     

Biological rhythms of cells of the lymphoid series in the thymus-dependent zone of lymph nodes

Biological rhythms of density in the lymphoid line cell populations (small and middle lymphocytes, immunoblasts, plasmoblasts, immature and mature plasmocytes) have been investigated in the thymus-dependent zone of the mouse axillary lymph nodes. The observations have been performed for 572 h. The amount of the cells is counted over the nodes of the morphometrical net. The results of the observations are treated by means of the spectral cosinor-analysis. Circadian or similar to it rhythmicity is peculiar for all the types of the cells, besides plasmoblasts. Within the ultradian range rhythmicity of the small lymphocytes, immunoblasts and immature plasmocytes is presented by two components, and that of the plasmoblasts--by one. The complexity of the rhythm components demonstrates that the course of the process during the observation time does not repeat strictly every day running, since periods of the circadian components somewhat fluctuate from 24 h, and periods of the ultracircadian ones--do not make multiple parts from the duration of the circadian periods. The time of picks and troughs of the amount of the cells during successive 24 h also do not coincide with each other, as the circadian and ultradian components interact. During one 24-hour's period the curve does not possess a regular sinusoid form and additional picks and troughs are revealed, since certain oscillations of a higher frequency participate in the process. These data are necessary to estimate reactions at T-immunological response.     

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.     

Structure of the small-intestinal lymphoid patches in albino rats at various stages of their development

The following stages in lymphoid patches (LP) development have been revealed: I-1-6, II-7-14, III-15-21, IV-22-30 days; during these periods lymphoid noduli with germinative centers, cupolae and internodular areas are formed. Amount of all kinds of cells in the LP parenchyma and their rearrangement in the zones takes place. In one-month-old rats blast forms predominate in the LP germinative centers, and small lymphocytes--in the zone of small lymphocytes of the noduli and internodular areas. Under conditions of antenatal effect of an antibiotic on the system mother--fetus there is no disturbances in formation of the anatomical structures. However at each stage of development the small intestine LP are not mature, concerning their cellular composition. Amount of cells decreases, their interrelationship changes. Lympho- and plasmocytopoiesis decreases.     

Circadian variation of the response of T cells to antigen

Circadian clocks regulate many important aspects of physiology, and their disturbance leads to various medical conditions. Circadian variations have been found in immune system variables, including daily rhythms in circulating WBC numbers and serum concentration of cytokines. However, control of immune functional responses by the circadian clock has remained relatively unexplored. In this study, we show that mouse lymph nodes exhibit rhythmic clock gene expression. T cells from lymph nodes collected over 24 h show a circadian variation in proliferation after stimulation via the TCR, which is blunted in Clock gene mutant mice. The tyrosine kinase ZAP70, which is just downstream of the TCR in the T cell activation pathway and crucial for T cell function, exhibits rhythmic protein expression. Lastly, mice immunized with OVA peptide-loaded dendritic cells in the day show a stronger specific T cell response than mice immunized at night. These data reveal circadian control of the Ag-specific immune response and a novel regulatory mode of T cell proliferation, and may provide clues for more efficient vaccination strategies.     

Cellular composition of various structural zones of the iliac and mesenteric lymph node of pregnant rats

The dynamic of cellular reactions demonstrates certain changes in functional activity of all structures of the node during pregnancy. A similar trend of processes in the iliac (regional for the uterus) and mesenteric lymph nodes has been defined. At early stages of pregnancy, lymph nodule are the most active, this is demonstrated as an increasing portion of lymphoblasts, macrophages and dividing cells. During this period, cell composition of the cortical plateau is relatively stable. For the paracortical zone of the mesenteric lymph nodes a rather significant decrease in the portion of middle lymphocytes and reticular cells is characteristic. There is not any significant change in the relative amount of the cells in the same functional zone of the iliac lymph nodes during the same period of pregnancy. The medullar cords demonstrate an increasing number of blast forms and young plasmocytes. However, as the pregnancy develops, the structure of the paracortical zone undergoes an essential change--progressively increases the portion of lymphoblasts and large lymphocytes. The blastic reaction in the mesenteric lymph nodes is proved to depend, to some extent, on that in the iliac lymph nodes of the same animal. Mature plasma cells become the dominating cellular element in the medullary cords. At the end of the pregnancy a relative amount of the reticular cells increases in all structural zones of the node.     

Morphology of mesenteric lymph nodes after balneologic procedures

Strong and weak sulfate baths produce certain increase in amount and in area of the lymphoid noduli with the germinative center, in the deep cortex and a decrease in the relative area of the medullary substance, while iodobromine baths facilitate to an outgrowth of the medullary cords and to ectasia of sinus lumens. After the balneoprocedures lymphoid noduli appear in the deep cortex; amount of destructive cells in the medullary sinuses, in the medullary cords and in the intermedullary zone decreases; amount of mast cells, eosinophiles and neutrophiles increases (slightly). Blast transformation of small lymphocytes and increase in number of middle lymphocytes are observed in the germinative centers.     

Changes in the H-alloantigen-recognizing function of mouse lymphoid cells following hydrocortisone administration]

The capacity of spleen, thymus, and bone marrow cells of intact (control) and of hydrocortisone-treated mice CBA to induce the lymph node type of graft-v-host reaction (GVHR) in hybrids F1 (CBA X c57bl) was studied. After hydrocortisone injection (2.5 mg per mouse) the donor spleen cells became more active in GVHR, considering the value of lymph node indices and immunoblast content in the regional lymph node as compared with a control group. Following transplantation of thymus cells taken from the hydrocortison-treated donors the immunoblast count was higher, although the lymph node weight remained the same as in the control group. On the contrary, following the transfer of the bone marrow cells from the hydrocortisone-treated mice the lymph nodes enlarged, while the immunoblast count remained as low as in control. Consequently, exogenously conditioned increase in the hydrocortisone level was accompanied by an enrichment of the spleen and thymus cell populations with T-lymphocytes, proliferating in response to H-alloantigens.     

Terminal galactosyl residues of cell-surface glycoconjugates exposed on both human and murine immature T- and B-cells

Summary Exposure of terminal galactosyl residues on cell-surface molecules as detected by their ability to bind peanut lectin (PNL) is found to be characteristic for immature cortical human and murine thymic lymphocytes. While in prenatal mice PNL staining is found to be uniformly distributed among all thymic lymphocytes, in adult thymi a cortico-medullary gradient is detectable concerning the PNL-binding capacity of thymic cortical lymphocytes, a phenomenon that appears to be correlated to their maturational degree.In secondary lymphatic tissue, i.e. lymph nodes and spleen of man, mouse and rat, strongly labeled cells are found exclusively in germinal centers. Ultrastructurally, these cells could be identified as centrocytes and centroblasts. These observations suggest that exposed galactosyl moieties of cell-surface glycoconjugates are expressed by undifferentiated lymphocytes of both T-and B-cell lineage.Furthermore, it could be shown that PNL-binding properties of immature cells are not restricted to lymphatic tissue but can also be demonstrated on various embryonic cells of non-lymphatic origin in distinct developmental stages. Thus, they might have a fundamental significance in the course of maturation processes.Supported by the Deutsche Forschungsgemeinschaft     

Surface immunoglobulin on rabbit lymphoid cells. II. Ultrastructural distribution of b4 allotypic determinants and morphology of spleen lymphocytes

Surface immunoglobulin allotypic determinants on rabbit spleen lymphoid cells are ultrastructurally localized by labeling with antiallotype antisera and soluble complexes of ferritin and rabbit antiferritin of a given allotype. At 0 °C surface Ig is visualized in patches on the membrane of 54% of the spleen lymphocytes examined. Four morphologically distinct categories of spleen lymphocytes display different amounts of labeled surface Ig. Type I cells are essentially identical to peripheral blood lymphocytes and demonstrate rapid endocytosis of surface Ig at 37 °C. Type II cells greater amounts of surface Ig, demonstrate little endocytosis, and are consistent with lymphoblast cells. Type III cells have the greatest amount of surface Ig, reveal some endocytosis, and are morphologically consistent with proplasmacytes and plasmablast cells. Type IV cells are immature plasma cells and have very little detectable surface Ig. The percentage of each cell type making up the labeled population is Type I, 28%; Type II, 21%; Type III, 50%, and Type IV, 1%. Immunoferritin labeled Ig determinants may be modulated from the surface of these cells at 37 °C by endocytosis and/or by shedding after reaction with anti-Ig antisera.     

Studies on the germinal center

Summary Ultrastructure of mitotic cells in human lymph node germinal centers was deliberately studied in contrast to that of plasma cells in mitosis which were rarely found in medullary cords or lymphatic sinuses of the same materials. It was demonstrated that the mitotic cells in germinal centers are evidently different from the latter in the absence of lamellary arranged endoplasmic reticulum with ribosomes and Golgi apparatus, and are quite similar to the ultrastructure of thymic lymphocytes in mitosis reported by Murray et al. It should be concluded from these findings that the cells produced locally within the germinal centers in human lymph nodes are lymphocytic as has been repeatedly suggested by the authors.Supported by Grant in Aid from the Ministry of Education of Japan (69-9254).