Selective labeling of mesenteric lymph nodes: Cell production and emigration ofnewly formed lymphocytes to other organs

Lymphocyte production by mesenteric lymph nodes of normal young pigs was studied by intranodal injections of either tritiated thymidine or tritiated deoxycytidine as DNA precursors. One or two days after selective labeling of the mesenteric lymph nodes the relative and absolute number of lymphocytes derived from mesenteric lymph nodes were determined autoradiographically in the following organs: mesenteric, cervical and inguinal lymph nodes, spleen, thymus, bone marrow, peyer'spatches, tonsil, different regions of the gut, lung and liver. The overall cell production of mesenteric lymph nodes, as derived from the sum of all labeled cells one day after labeling, was estimated to be about 7 × 10⁹ lymphocytes. Up to 40% of all newly formed lymphocytes had already left the lymph nodes within one day and were found in all organs studied. There was a preferential homing to the mucosa of the small intestine, but a considerable number migratedto the spleen and even to the thymus and bone marrow. In lymphoid organs all labeled cells were small and medium-sized lymphocytes one and two days after labeling. In cervical lymph nodes, spleen, tonsil and peyer's patches the relative distribution to T and B cell areas was determined. There was an obvious preference of newly formed lymph node cells to home to T cell areas. The differences of labeling between thymidine or deoxycytidine were surprisingly low.     

Migration of newly formed small lymphocytes from bone marrow to lymph nodes during primary immune response

Selective DNA labelling of bone marrow cells in vivo was used to determine the effect of antigenic stimulation on the migration of small lymphocytes from bone marrow to popliteal lymph nodes. Following footpad injection of keyhole limpet haemocyanin (KLH) in guinea-pigs the regional nodes showed an early increase in weight and cellularity together with a progressive increase in cell proliferation. When [³H]thymidine was injected into tibial and femoral marrow 2 days before KLH administration the DNA radioactivity of the KLH-stimulated nodes increased rapidly and always exceeded that of contralateral nodes. Simultaneously, in radioautographic sections of lymph nodes labelled small lymphocytes, indicative of an origin from marrow precursors, appeared throughout the cortex, post-capillary venules, subcapsular sinus, medullary cords and sinuses. In KLH-stimulated nodes the number of labelled small lymphocytes per section was higher than in contralateral nodes, especially in the cortex, and some of these cells appeared in germinal centres. Labelled large blast cells and macrophages were also increased in numbers. Similar changes were observed in lymph nodes of parental strain rats following intramyeloid [³H]thymidine administration and footpad injection of lymphoid cells from F1 hybrid rats. The results demonstrate that, during the early response of lymph nodes to various antigens, local changes in cell traffic include an enhanced accumulation of newly formed small lymphocytes, putative virgin B lymphocytes, generated in the bone marrow prior to the antigenic stimulation.     

Proliferation and emigration of newly formed lymphocytes from pig spleens during an immune response

Normal young pigs were immunized intravenously with sheep red blood cells (SRBC). At various times after a second SRBC injection the spleens were connected to an extracorporeal perfusion system, and proliferating lymphoid cells in the spleens were selectively labelled with tritiated thymidine. One day later the relative and absolute numbers of spleen-derived lymphocytes were determined by autoradiography in the following organs: various parts of the spleen, mesenteric and cervical lymph nodes, thymus, bone marrow, Peyer's patches, tonsils, intestine, lung, liver and blood. From 1 to 7 days after the second SRBC injection, the spleens produced increasing numbers of lymphocytes, and labelled cells were found especially in the blood and bone marrow. The newly formed splenic lymphocytes migrated preferentially to T- but also to B-cell areas in lymph nodes, Peyer's patches and tonsils. In all organs outside the spleen nearly all labelled spleen-derived lymphocytes were small lymphocytes. However, the bone marrow contained a high proportion of labelled immature and mature plasma cells. The spleen produced large numbers of lymphocytes during the secondary immune response, many of which migrated to different organs probably as memory cells, while others were found in the bone marrow as effector cells from the immune response.     

Mast cell responses in mesenteric lymph nodes to infection of rats with the nematode, Nippostrongylus brasiliensis

The number of mast cells and their distribution in rat mesentery lymph nodes were assessed after a primary infection and after several successive infections with the nematode, Nippostrongylus brasiliensis. Following primary infection with N. brasiliensis, two peaks in total mast cell counts were observed. An initial small increase was restricted to day 5 and to the region of entrance to the lymph node. During the second peak, a marked increase in the number of mast cells occurred after day 15, the majority of cells is migrating through the afferent lymphatics, and then advancing from the cortical to the medullary region. The number of cells found in the hilus always remained low, indicating that mast cells accumulate and degranulate within the lymphoid organ.

In rats infected several times with the nematode parasite, mast cell numbers were markedly increased and the distribution pattern was similar to that found on day 21 after a primary infection. The observation that the percentage of cells found in the capsule was rather low in these animals indicates that local proliferation might have contributed to the high mast cell counts.

     

Ability of intestinal Escherichia coli to survive within mesenteric lymph nodes.

Identification of mesenteric lymph node (MLN) bacteria showed that indigenous streptomycin-sensitive Escherichia coli could be recovered from MLN at least 48 h after this organism had been essentially eliminated from the cecal flora by antibiotics and replaced with exogenous streptomycin-sensitive E. coli JK. Additional experiments with antibiotic-treated rats also showed that indigenous streptomycin-sensitive E. coli could be recovered from the MLN 4 days after elimination of this organism from the cecal flora. These findings suggest that the time of bacterial translocation to MLN may be kinetically different from the time of recovery of bacteria from MLN and that the MLN may be a focus of infection with intestinal bacteria.     

In situ demonstration of dendritic cell migration from rat intestine to mesenteric lymph nodes: relationships to maturation and role of chemokines

Dendritic cells (DCs) are continuously transported from the intestine to mesenteric lymph nodes (MLNs). The objective of this study was to determine the migration kinetics of DCs via intestinal lymph and to investigate regulatory factors affecting their migration in vivo. DCs were obtained from spleen or thoracic duct lymph of mesenteric lymphadenectomized rats. The DCs were fluorescently labeled and injected into the subserosa of the small intestine near the cecum, and their migration patterns into MLNs were determined. Isolated DCs from intestinal lymph express intercellular adhesion molecule-1 (ICAM-1), CD11b/c, CD80/86, and major histocompatibility complex class II but maintain their ability to phagocytize latex particles, suggesting the presence of immature DCs. The isolated DCs accumulated in MLNs in a time-dependent manner with maximal accumulation at 48 h. Cytokine-induced maturation of lymph DCs did not cause a change in cell number but accelerated their transport into MLNs with a maximum at 24 h. Splenic DCs showed an intermediate level of maturation and a migration pattern similar to mature DCs. Inhibition of ICAM-1 or CD11b/c did not affect DC migration. Migration of mature DCs to MLNs was specifically blocked by desensitization of CCR7 with CCL21. In contrast, freshly isolated lymph DCs were not chemotactic for CCL21, but their migration to MLNs was mainly inhibited by desensitization of CCR6 with CCL20. The migratory ability of DCs correlates well with their degree of maturation, and different chemokine/chemokine receptor use may be the main regulator of DC migration kinetics through intestinal lymph.     

The appearance of fluorescein-labelled lymphocytes in lymph following in vitro or in vivo labelling: the route of lymphocyte recirculation through mesenteric lymph nodes

Fluorescein isothiocyanate (FITC) has been used to study lymphocyte migration in sheep. After being labelled in vitro with FITC, lymphocytes migrated from blood into lymph at the same rate and with the same recovery as lymphocytes labelled with with the radioisotope 51chromium. The in vivo labelling of mesenteric lymph nodes (MLN) with FITC resulted in high numbers of labelled lymphocytes appearing in prescapular lymph. However, the appearance of the FITC-labelled lymphocytes in the prescapular lymph could be prevented by cannulating the main intestinal lymph duct prior to the in vivo labelling procedure. It was concluded that lymphocytes labelled in vivo within the MLN required an intact lymphatic system to reach the blood circulation and did not enter the venous circulation directly from the MLN.     

多排螺旋CT在检测肠系膜淋巴结中的应用及其意义

目的以健康人群为研究对象,探讨肠系膜淋巴结在薄层螺旋CT图像上的分布特点及其临床意义。方法选择60例健康体检者,其中男性35例,女性25例;年龄26～67岁,平均年龄55岁。用Siemens Definition AS 128层螺旋CT进行腹部扫描,成像参数:120 kV,280 mA,128 i×0.6 mm,0.5 s/r,螺距0.6,扫描层厚、层间距均为8 mm。由3名放射学工作者应用同一图像贮存和传输系统(PACS)工作站阅读所有CT图像,记录所有短轴大于3 mm的肠系膜淋巴结的大小、数目及位置(肠系膜根部、周边肠系膜或右下腹肠系膜区)。结果有54例检测到短轴直径大于3 mm肠系膜淋巴结,其中12例(22.2%)检测到10个以上淋巴结,31例(57.4%)检测到5个以上淋巴结,其余11例(20.4%)检测到5个以下淋巴结。同时所有体检者都检测到多个短轴直径小于3 mm的肠系膜淋巴结,短轴直径多为2 mm左右。在所有检测到的淋巴结中,最大淋巴结直径范围为5.4～9.2 mm,平均直径范围为3.5～6.5 mm。54例中,肠系膜根部发现较多淋巴结者25例(46.3%),右下腹肠系膜区22例(40.7%),肠系膜周边部7例(13.0%)。结论128层螺旋CT能检出更多、更小的肠系膜淋巴结。这些淋巴结直径可小于3 mm。在健康人群中发现这些淋巴结,无临床意义,不需要进一步的影像学检查及临床治疗。     

Polypoid gastrointestinal stromal tumor of small bowel metastasizing to mesenteric lymph nodes: a case report

Gastrointestinal stromal tumor (GIST) is the commonest gastrointestinal mesenchymal tumor, which rarely metastasizes to lymph nodes. Therefore, unlike cases of adenocarcinoma, lymphadenectomy is seldom warranted. We describe an unusual case of a polypoid GIST of the small bowel which metastasized to the regional mesenteric lymph nodes at the time of primary surgery. The patient was a 79-year-old female who presented with partial bowel obstruction and anemia. The presented case has three unusual features, as the tumor was grossly pedunculated, microscopically pleomorphic, and featured mesenteric lymph node metastasis at the time of diagnosis.     

The migration of lymphocytes from bone marrow to popliteal lymph nodes demonstrated by selective bone marrow labeling with 3H-thymidine in vivo

Guinea pig popliteal lymph nodes were examined by DNA radioassay and radioautography following the selective labeling of tibial and femoral marrow cells by intramyeloid injections of ³H-thymidine. The DNA radioactivity of the node increased for the first four days and at four to seven days exceeded that seen after an intraperitoneal injection of the same total dose of ³H-thymidine, indicating an export of radioactivity from the labeled marrow to the node. Simultaneously, radioautographic sections of the node revealed labeled cells indicative of an origin from marrow precursors. Small lymphocytes constituted 60–90% of the labeled cells and reached maximal numbers at four to six days. Most of them were observed in the cortex, including the subcapsular sinus, primary follicles, mantle zones around germinal centers, and the lumen and walls of post-capillary venules. However, the highest labeling indices of small lymphocytes occurred in the medulla, including the medullary cords, medullary sinuses and efferent lymphatic vessels. Labeled large mononuclear cells, including large lymphoid cells, monocytes and large blast cells, were confined almost exclusively to the cortex. A small number of labeled plasma cells was observed in the medullary cords. It is concluded that newly-formed bone marrow lymphocytes migrate continuously into immunologically quiescent lymph nodes and become widely distributed throughout the cortex and medulla, while some enter the recirculating small lymphocyte pool.     

Immunologic characterization of Reed-Sternberg cells and other cell components in lymph nodes with Hodgkin's disease

Seven lymph nodes from patients with Hodgkin's disease were immunologically studied. Histologically these cases consisted of 3 lymphocyte predominance, 2 mixed cellularity, and 2 nodular sclerosis. Positive staining of mononuclear Hodgkin- and multinuclear Reed-Sternberg (RS) cells were obtained with anti-Ia like antigens and OKT9 (anti-transferrin receptor) monoclonal antibodies. No supportive data for discussing similarity of RS cells with ordinary histiocytes, B-lymphocytes or T-lymphocytes were obtained from the study of surface phenotype, although some analogy was present with histiocytes. Small lymphocytes around RS cells were helper/inducer T-lymphocytes, and the relationship between these T lymphocytes and RS cells was discussed.     

CD4+ lymphocytes are extracted from blood by peripheral lymph nodes at different rates from other T cell subsets and B cells

The circulation of lymphocyte subsets through prescapular lymph nodes in sheep has been quantified using a panel of monoclonal antibodies against sheep lymphocyte surface antigens. Differences in the extraction of lymphocyte subsets from blood by the lymph node were found with CD4+ lymphocytes being extracted at a faster rate (1/2) than CD8+, SBU-T19+, major histocompatibility complex class II+ and B cells (1/4 to 1/5). In order to accommodate existing data on organ-specific adhesion molecules, one subset specific and one tissue specific, expressed on vascular endothelium could act jointly to regulate the migration of recirculating lymphocytes.     

The mononuclear cells of human mesenteric blood, intestinal mucosa and mesenteric lymph nodes: compartmentalization of NK cells.

The proportions of T cell subsets and Leu 7+ cells and the spontaneous cell-mediated cytotoxicity (SCMC) of isolated mononuclear cells have been determined across the mesenteric vascular bed and along the intestinal mucosal-mesenteric lymph node (MLN) axis in patients undergoing abdominal surgery. Whereas the proportion of T4+ and T8+ cells were similar in simultaneously taken PVB and mesenteric venous blood (MVB), the proportion of Leu 7+ cells was higher in MVB in 16 of 17 studies (15.4 +/- 6.8%, 10.8 +/- 5.1%). Additional studies showed that the proportions of lymphocyte subsets in peripheral arterial blood are the same as those in PVB. Thus, an enrichment of Leu 7+ cells occurs across the mesenteric vascular bed. Isolated intestinal and MLN mononuclear cells contained similarly high proportions of T4+ and T8+ cells as in PVB but Leu 7+ cells made up a minority subpopulation in intestinal (1.3 +/- 0.8%) and MLN mononuclear cells (1.0 +/- 0.9%). The SCMC of intestinal and MLN mononuclear cells was low and paralleled the proportion of Leu 7+ cells. Despite the higher proportions of Leu 7+ cells in MVB, the SCMC was less than that of PVB in eight patients with inflamed intestine and not significantly different from PVB in seven patients with normal intestines. These paradoxical findings were at least in part due to inhibitory factors in mesenteric plasma. In conclusion, NK cells appear to be largely confined within the vascular system and the enrichment of Leu 7+ cells across the mesenteric vascular bed suggests that this compartmentalization may be due to differences in the traffic of lymphocyte subpopulations through the intestinal mucosa and MLN.     

Colon composited B cell lymphoma involving intestinal mesenteric lymph nodes combined with adenocarcinoma and schistosome infection: a case report

Here we reported one rare case of colon composited B cell lymphoma associated with adenocarcinoma. The composited B cell lymphoma composed of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) and large B-cell lymphoma. Additionally, adjacent intestinal mesenteric lymph modes were involved. And interestingly, schistosome infection was also found in lymphoma and adjacent tissues. The patient was given a usual local intestinal resection for colon adenocarcinoma. But in the site of one surgical margin, 10 cm away from intestinal carcinoma, we found another mass. Beneath the neoplasm, several swollen intestinal mesenteric lymph nodes were detected. By H&E staining and immunohistochemistry, it was eventually demonstrated the patient suffered complicated neoplasms. So far, there were just several references about colon lymphoma combined with adenocarcinoma. But the present case is the first to report that colon composited B cell lymphoma associated with adenocarcinoma and schistosome infection.     

Relationship between cecal population levels of indigenous bacteria and translocation to the mesenteric lymph nodes.

Translocation is defined as the passage of viable bacteria from the gastrointestinal tract to the mesenteric lymph nodes (MLN) and other organs. The extent of translocation of certain indigenous, oxygen-tolerant bacteria from the cecum to the MLN, spleen, liver, kidney, and peritoneal cavity were determined in diassociated or triassociated gnotobiotic mice. Minimal bacterial translocation occurred to the spleen, liver, kidney, or peritoneal cavity. However, most bacterial strains readily translocated to the MLN. The percentage of the total population of each bacterial strain in the ceca was compared with the percentage of the total population of that strain in the MLN. There was a direct relationship between the numbers of a particular bacterial strain populating the ceca of diassociated or triassociated mice and the numbers of viable bacteria of this strain present in the MLN. Thus, the cecal population level of a particular bacterial strain determined the numbers of viable bacteria of this strain translocating to the MLN. The translocation of these bacterial strains from the gastrointestinal tract is an important first step in the pathogenesis of infection caused by members of the normal intestinal microflora.