Comparative migration of B- and T-Lymphocytes in the rat spleen and lymph nodes.

B-lymphocytes were obtained either by thoracic duct cannulation of thymectomized, irradiated rats or by isolation of complement-receptor-bearing lymphocytes from normal rats. They were labeled in vitro with [³H]-leucine and injected iv into syngeneic recipients from which samples of spleen and lymph node were taken at intervals from 15 min to 48 hr after injection. The sites of initial localisation of B- and T-lymphocytes were identical suggesting that the cells migrated into both organs by a common entrance. The two cell types remained closely associated for several hours in the paracortex of lymph nodes and at the periphery of the periarteriolar lymphoid sheath of the spleen. After 1–6 hr, B-cells segregated from T-cells by moving on into the adjacent part of the lymphocyte corona in the follicular area. By 24 hr, B-cells were evenly distributed throughout the corona. A definite minority of B-cells but no T-cells were seen within the germinal centres. In the spleen, T-cells moved into the central area of the periarteriolar sheath before returning to the blood. The immunological significance of the routes of B- and T-cell migration is discussed.     

Changes in rat leukocyte populations in peripheral blood, spleen, lymph nodes, and synovia during Erysipelas bacteria-induced polyarthritis.

Kinetics of leukocyte subsets were followed for several weeks in rats suffering from polyarthritis induced by experimental infection with erysipelas bacteria (Erysipelothrix rhusiopathiae, serovar 2, strain T28). A marked leukocytosis was found in peripheral blood, and, with some delay, in the synovia and draining lymph nodes of affected joints. In the lymphoid organs tested considerable blast formation of lymphoid cells with a paucity of polymorphonuclear granulocytes was found, while the latter represented the majority of leukocytes in acutely inflamed joints. Cells isolated from spleen showed only moderate and transient alterations in proportions of subpopulations during the first week after inoculation of erysipelas bacteria. In contrast, cells isolated from synovia of inflamed joints and draining lymph nodes displayed more intense and longer lasting alterations: In arthritic animals, the proportion of MHC class II-positive lymphocytes generally increased and remained elevated at least during the first three weeks of the disease. Spontaneous release of IL-2 from cells isolated up to 20 days post induction of the arthritis indicated a considerable activation of lymphocytes in vivo. Interestingly, with exception of synovia, the relative amount of T-lymphocytes including their major CD4+ and minor CD8+ subsets showed little alteration during the course of the disease. Much more pronounced were the rapidly and the extent the membrane Ig-positive B-lymphocytes increased in the synovia as well as in the lymph nodes. Thus, B-lymphocytes may be of particular relevance for elucidating pathomechanisms of erysipelas polyarthritis.     

Ontogenetic aspects of immune-complex trapping in the spleen and popliteal lymph nodes of the rat

Summary An ontogenetic approach was used to obtain information about the relation between structure and function of lymphoid tissues. In particular the development of the capacity to trap immune complexes was studied in relation to the development of the lymphoid compartments. For this purpose isologous horseradish (HRP)-anti-HRP complexes were injected into neonatal rats, and their fate was studied in the spleen and popliteal lymph nodes. Immune-complex trapping occurred as soon as primary follicles could be recognized; without follicles no trapping was observed. Several explanations for this simultaneous development of trapping capacity and follicular structure are discussed.Abbreviations i.v. intravenous(ly) - s.c. subcutaneous(ly) - HRP horseradish peroxidase - MZ marginal zone - PALS periarteriolar lymphocyte sheath     

Clasmatosis: Ultrastructure of cytoplasmic fragments from the spleen,lymph nodes,and thymus of the rat

Summary The cytoplasmic fragments forming as a result of clasmatosis were isolated by centrifugation from cellular suspensions of the spleen, submandibulur lymph nodes and thymus of August rats and were studied electron microscopically. It has been established that the cytoplasmic fragments widely vary in organelle saturation within the same organ and that this saturation diminishes in the spleen-lymphatic nodes-thymus series. With the exception of the centrioles and the Golgi complex the cytoplasmic fragments may contain any cytoplasmic organelles and inclusions characteristic of lymphoid cells. The results have been discussed from the point of view of the possible relation of clasmatosis to the process of lymphocyte maturation.     

Time course of the ventilatory response to adjuvant arthritis in the rat

The present study determined the time course of the ventilatory response to adjuvant arthritis in the rat. It was found that the minute ventilation of arthritic rats reliably exceeded that of control animals during a period of about 4 weeks. The ventilatory response had its onset during the 2nd week after inoculation of $\text{Mycobacterium butyricum}$ in the tail base, peaked on day 21, and was statistically reliable up to the 35th day. A smaller difference persisted throughout the further six weeks of the study, which covered 77 days in all. The changes in minute ventilation appeared to be closely time-locked with the changes in body weight and paw diameter which are characteristic of rats with adjuvant arthritis. The peak minute ventilation of individual animals also correlated in a significant manner with changes in weight and in paw diameter. The data are consistent with an earlier attempt to characterize the time course of the chronic pain which is presumably associated with adjuvant arthritis in the rat; minute ventilation is discussed as a possible measure of this putative pain.     

Intramuscular electroporation with the pro-opiomelanocortin gene in rat adjuvant arthritis

Endogenous opioid peptides have an essential role in the intrinsic modulation and control of inflammatory pain, which could be therapeutically useful. In this study, we established a muscular electroporation method for the gene transfer of pro-opiomelanocortin (POMC) in vivo and investigated its effect on inflammatory pain in a rat model of rheumatoid arthritis. The gene encoding human POMC was inserted into a modified pCMV plasmid, and 0-200 microg of the plasmid-POMC DNA construct was transferred into the tibialis anterior muscle of rats treated with complete Freund's adjuvant (CFA) with or without POMC gene transfer by the electroporation method. The safety and efficiency of the gene transfer was assessed with the following parameters: thermal hyperalgesia, serum adrenocorticotropic hormone (ACTH) and endorphin levels, paw swelling and muscle endorphin levels at 1, 2 and 3 weeks after electroporation. Serum ACTH and endorphin levels of the group into which the gene encoding POMC had been transferred were increased to about 13-14-fold those of the normal control. These levels peaked 1 week after electroporation and significantly decreased 2 weeks after electroporation. Rats that had received the gene encoding POMC had less thermal hypersensitivity and paw swelling than the non-gene-transferred group at days 3, 5 and 7 after injection with CFA. Our promising results showed that transfer of the gene encoding POMC by electroporation is a new and effective method for its expression in vivo, and the analgesic effects of POMC cDNA with electroporation in a rat model of rheumatoid arthritis are reversed by naloxone.     

Immunostimulatory DNA sequences influence the course of adjuvant arthritis.

Bacterial DNA is enriched in unmethylated CpG motifs that have been shown to activate the innate immune system. These immunostimulatory DNA sequences (ISS) induce inflammation when injected directly into joints. However, the role of bacterial DNA in systemic arthritis is not known. The purpose of the present experiments was to determine whether ISS contributes to the development of adjuvant arthritis in Lewis rats after intradermal injection of heat-killed Mycobacterium tuberculosis (Mtb). The results showed that Mtb DNA was necessary for maximal joint inflammation in adjuvant arthritis but could be replaced by synthetic ISS oligodeoxynucleotides. The arthritis-promoting effect of the Mtb DNA or of the ISS oligodeoxynucleotides correlated with an increased Th1 response to Mtb Ags, as measured by the production of IFN-gamma and increased production of the osteoclast differentiation factor, receptor activator of NF-kappaB ligand (RANKL). The Mtb DNA did not enter the joints but dispersed to the bone marrow and spleen before the onset of systemic joint inflammation. Thus, adjuvant arthritis is a microbial DNA-dependent disease. In this model, we postulate that massive and prolonged activation of macrophages, dendritic cells, and osteoclast precursors in the bone marrow may prime the joints for the induction of inflammatory Th1 immune responses to Mtb Ags.     

Osmium-zinc iodide reacts with interdigitating cells in the mouse lymph nodes and spleen.

It is known that epidermal Langerhans cells react with osmium-zinc iodide (ZIO) mixtures; therefore they can be visualized by this histochemical method. In the last few years it has been shown that Langerhans cells are closely related to the class of interdigitating cells (IDC) which are antigen presenting cells located in the T-dependent areas of lymph nodes and spleen. In this study the reactivity of murine IDC to ZIO has been assessed. Results demonstrate that ZIO procedure yields to a brilliant and selective staining of IDC. The reactivity pattern is quite similar to that previously observed in epidermal Langerhans cells. This finding gives further support to the concept that Langerhans cells and IDC are closely interrelated cell types.     

Pathomorphologic characteristics of the regional lymph nodes in hydronephrosis]

The dependence of pathomorphological changes in the regional lymphatic ganglia of the dog's kidney upon the duration of experimental hydronephrosis is shown. The development of necrosis in some of them points out indirectly to the participation of the renal lymphatic system in carrying off the urine saturated with toxic products persisting in it for a long period. Increased dilatation of intermediate and medullary sinuses is connected with continuous inflow of the lymph that contributes to its congestion and then leads to the retrograde flow. A mechanical obstraction appears on the way of lymph and this fact aggravates mechanical insufficiency of the lymph circulation. At the same time this particular case is lymphogenic sclerosis, which is induced by acumulation of disturbed metabolism products in the intermediate tissue brought by the lymph.     

On the dynamics of T-cell activation in lymph nodes

The immune system is a complex network comprising many different organs and cell types, all of which have to work together in a highly accurate manner to exert their function. How is it, then, that the key players of adaptive immunity, T cells, B cells and dendritic cells (DC) move through this network? How is compartmentalization maintained and how do they interact? Over the past decade much attention has been paid to how and where T-cell/DC interactions take place, but only recently--with the advent of new techniques--has research been directed to investigate 'live' T-cell/DC interactions ex vivo and in situ. Whereas the overall sequence of events leading to T-cell activation is largely undisputed, many of the cellular and molecular details of early T-cell priming remain undefined or controversial. This review will focus on recent findings and discuss their implications for T-cell activation.     

Cytotoxicity of effector cells of the peripheral blood, lymph nodes and spleen in Hodgkin's disease

The mononuclear cells and T-lymphocytes of the blood, spleen and lymph nodes from 83 patients with Hodgkin's disease and 50 healthy donors were tested in assays for lectin-dependent (LD) and natural killer (NK) cytotoxic activity (CTA). On an average, peripheral blood T cell LD-CTA of patients did not differ from that of the donors. However, the CTA appeared to be dependent on the stage of the disease; in the IVth stage LD-CTA was decreased 2-fold. The LD-CTA was also dependent on the histological type of disease and the lowest level of LD-CTA (50% of the control level) was associated with the "lymphocyte depletion" type. The CTA of T-lymphocytes from the affected areas of the patients' spleen was more marked than that of the unaffected areas. Spleen cell CTA showed no other correlations. The CTA of lymphocytes from the affected lymph nodes was drastically lower than CTA of blood and spleen lymphocytes. The NK activity of the patients' blood and spleen lymphocytes was twice as less as the control level (healthy donors) and did not correlate with a stage and/or a histological type of the disease. It was assumed that in Hodgkin's disease the specific antitumor immunity remains mostly within normal and is decreased only in the last, terminal stage of the disease.     

Extra-organic lymphatic vessels and regional lymph nodes of the kidneys in dogs

An anatomical investigation of extraorganic lymphatic vessels and regional renal lymph nodes has been performed in 70 dogs. The regional lymph nodes in the right kidney are stated to be quantitatively constant, as well as cranial and caudal lateroaortal lymph nodes in the left kidney in regard to the middle left lateroaortal nodes, that get lymph from the left kidney parenchyma. One middle left lateroaortal lymph node is found in 47 animals examined, two lymph nodes--in 17 animals. In 6 cases a lymphatic vessel, that gets lymph from the renal parenchyma and independently runs into the cistern of the thoracic duct is found for the first time. The variant revealed is an exception from the rule known in lymphology: lymph in its way from periphery to the central collector runs, at least, through one lymph node.     

Structure of the non-lymphoid cells during the postnatal development of the rat lymph nodes

This study describes the postnatal development of the nonlymphoid cells with special reference to the fibroblastic reticulum cells (FRCs) and interdigitating cells (IDCs). The first lymphocytes of the neonatal lymph nodes are located in the developing deep cortex units (DCUs) identified by the Gomori's technique for reticulin fibres. Ultrastructural studies demonstrate that FRCs form the stroma of the DCUs. By light and electron microscopy, it is demonstrated that FRCs occupy the outer cortex in the following stages of development of the lymph nodes. Thus, FRCs form the stroma of the primary follicles and, later, are transformed in follicular dendritic cells (FDCs) of the germinal centres. Immature or pro-IDCs appear as migrating elements in the deep cortex of lymph nodes of the neonatal rats. The ultrastructure of the pro-IDCs resembles that of the mature IDCs but not that of the phagocytic cells. Pro-IDCs are transformed into mature IDCs whose cytoplasmic expansions contact lymphocytes via tight junctions. Some of these lymphocytes are likely apposed to FRCs of the DCUs. No cells containing Birbeck granules were found in the parenchyma of the lymph nodes during the postnatal development. The role of these nonlymphoid cells is discussed with respect to the immunologic function of mammalian lymph nodes.