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PubMed1975

Further observations of Fc receptors in human malignant tissue and normal lymphoid tissue.

Twenty human malignant solid tumors of various histologic types were tested for the presence of Fc receptor using cryostat sections or single cell suspensions of fresh tissue. Sheep erythrocytes sensitized by various amounts of rabbit IgG antibodies served as indicator cells (EA). All tumors possessed Fc receptor, but to varying degrees; eight reacted more strongly than normal spleen without any relation to histologic type. The tumors which gave the strongest reactions in sections also formed the highest percent of EA rosettes in suspensions, thus indicating surface localization of receptors. The reactions with spleen sections localized to the B cell and monocytic areas; the latter also showed high avidity in reactions with uncomplexed IgG. Rabbit antisera to tumors, spleen, and peripheral lymphocytes (polyvalent ALS) in inhibited the reactions, while a T-cell-specific ALS did not. Absorptions of the antisera with lymphocytes or tissue sediments of spleen and tumors removed the inhibiting activity, tissue sediments of muscle and kidney only reduced the titers. Again, results with spleen sections paralleled those obtained with tumor sections. Apparently, the tumor Fc receptor is very similar to the Fc receptors present in normal lymphoreticular tissues.

Absorption↗
PubMed2006

Perinodal adipose tissue and fatty acid composition of lymphoid tissues in patients with and without Crohn's disease and their implications for the etiology and treatment of CD.

The physiological bases for roles of adipose tissue and fatty acids in the symptoms and dietary treatments of Crohn's disease are poorly understood. The hypothesis developed from experiments on rodents that perinodal adipocytes are specialized to provision adjacent lymphoid tissues was tested by comparing the composition of triacylglycerol fatty acids in homologous samples of mesenteric adipose tissue and lymph nodes from patients with or without Crohn's disease. Mesenteric perinodal and other adipose tissue, and lymph nodes, were collected during elective surgery for Crohn's disease and other conditions. Fatty acids were extracted, identified, and quantified by thin-layer and gas-liquid chromatography. Perinodal adipose tissue contained more unsaturated fatty acids than other adipose tissue in controls, as reported for other mammals, but site-specific differences were absent in Crohn's disease. Lipids from adipose and lymphoid tissues had more saturated fatty acids, but fewer polyunsaturates in Crohn's disease patients than controls. In adipose tissue samples, depletion of n-3 polyunsaturates was greatest, but n-6 polyunsaturates, particularly arachidonic acid, were preferentially reduced in lymphoid cells. Ratios of n-6/n-3 polyunsaturates were higher in adipose tissue but lower in lymphoid cells in Crohn's disease patients than in controls. Site-specific differences in fatty acid composition in normal human mesentery are consistent with local interactions between lymph node lymphoid cells and adjacent adipose tissue. But these site-specific properties are absent in Crohn's disease, causing anomalies in composition of lymphoid cell fatty acids, which may explain the efficacy of elemental diets containing oils rich in n-6 polyunsaturates.

Adipose Tissue↗
PubMed2005

Frequency and potential cause of bronchus-associated lymphoid tissue in fetal lungs.

Bronchus-associated lymphoid tissue consists of lymphoid follicles with or without a germinal center within the bronchial wall. Bronchus-associated lymphoid tissue is part of the integrated mucosal immune system and present in about 50% of healthy infants. We examined a series of 141 fetal and neonatal lungs and detected bronchus-associated lymphoid tissue in 100% of cases with amniotic infection while postpartum perinatal pneumonia did not elicit bronchus-associated lymphoid tissue formation. Only rarely and in low density, bronchus-associated lymphoid tissue was present in non-infected fetuses. The in utero formation of bronchus-associated lymphoid tissue seems to be a reactive phenomenon and - as has been shown in another study - does not portend an adverse prognosis.

Autopsy↗
PubMed1988

Effect of cortisol on the plasma and lymphoid tissue distributions of tritiated glucocorticoids in C57BL/6 mice.

The mechanism of action of very high doses of corticosteroids, such as those administered as bolus doses in the treatment of inflammatory and immune diseases or those currently used in rodents to isolate the small proportion of medullary thymocytes considered to be corticoresistant, is still undefined. The possible existence of selective local concentration by some tissues, particularly lymphoid organs, cannot be excluded. Therefore, using C57BL/6 mice, the kinetics of lymphoid tissue and plasma radioactivities after i.p. injection of steroids, either alone or with an excess of non-radioactive cortisol hemisuccinate (up to 10 mg/animal, i.e. 500 mg/kg) were studied. There was a rapid and dose-dependent retention of [3H]corticosterone and [3H]cortisol in the thymuses of cortisol-treated compared with control animals. The spleen also appeared to be capable of accumulating steroids. However, when the tissue/plasma ratio of [3H]steroid concentration and the change in extracellular space in the presence of an excess of nonradioactive cortisol were taken into consideration, only the thymus was able to concentrate steroids above concentrations in the plasma. Moreover, this effect did not appear to be specific for glucocorticoids, since tracer accumulation was also observed when sex steroids were used as tracers. The cells of the reticulo-endothelial system may, in part, be responsible for this phenomenon of steroid concentration in lymphoid organs.

Animals↗
PubMed1992

The role of nasopharyngeal lymphoid tissue.

Nasal-associated lymphoid tissue (NALT), which comprises paired lymphoid organs in the nasopharynx of rodents, is the principal mucosal lymphoid tissue of the respiratory tract. As described in this review, NALT bears certain similarities to the Peyer's patches of the intestine but the two differ remarkably in morphology, lymphoid migration patterns and the binding properties of their high endothelial venules (HEV).

Animals↗
PubMed1982

Intrapulmonary lymphoid tissue in mink infected with Aleutian disease virus.

Pulmonary lymphoid tissue was studied histologically in mink infected experimentally and naturally with Aleutian disease virus, an infection characterised by systemic lymphoid tissue hyperplasia. Lymphoid tissue hyperplasia was observed in the lamina propria of the bronchial tree, in perivascular tissue, in interlobular septae and subpleurally by day 42 after experimental aerosol infection. Four forms of pulmonary lymphoid tissue were recognised: lymphoepithelial nodules or bronchus-associated lymphoid tissue; lymphoid clusters; lymph nodes and diffuse lymphoid tissue. The cel components of these pulmonary reactions were indistinguishable from those seen in the kidney and the liver of the same experimental animals, except for lymphoepithelial nodules which have a specialised association with respiratory epithelium. Pulmonary lymphoid tissue hyperplasia was a significant feature of experimental aerosol infection with Aleutian disease virus but not of natural infections with this virus.

Aleutian Mink Disease↗
PubMed1989

Relative V beta transcript levels in thymus and peripheral lymphoid tissues from various mouse strains. Inverse correlation of I-E and Mls expression with relative abundance of several V beta transcripts in peripheral lymphoid tissues.

We have measured the relative levels of transcripts for 15 of the 22 known V beta gene segments. The level of transcripts for the highest and lowest expressed V beta gene segment differed by greater than 20-fold in the thymus and an even larger difference was observed in the periphery. The levels of expressions were unrelated to the order of the V beta genes on the chromosome. For most of the V beta gene segments, the relative transcript levels were the same in the thymus and periphery, suggesting that thymic selection in general does not act solely upon the V beta gene segment. One V beta gene segment in the BALB and B10 mice strains was an exception to this rule. V beta 5.2 expression in the periphery of BALB and B10 mice inversely correlated with the expression of the MHC class II molecule I-E. Five V beta gene segments had reduced transcript levels in the periphery of Mls-1a mice compared with their thymic levels or to the levels found in Mls-1b mice. The peripheral level of V beta 3 transcripts vary with MHC and Mls-2 haplotypes. The observation that certain V beta transcript levels are reduced in the periphery when compared with the thymus favors the hypothesis that self tolerance at the T cell level results in the elimination of self-reactive T cells, rather than paralysis by a block at some post-transcriptional step. Finally, the wide variability of V beta gene segment expression in the thymus suggests mechanisms exist to import an early bias to the repertoire. Whether this bias results from differential V beta segment rearrangement rates, differential V beta expression rates, or events occurring after TCR-alpha/beta expression on immature/nonmature thymocyte cell surfaces is yet to be determined.

Animals↗
PubMed1990

Morphologic studies of intrapulmonary airway mucosa-associated lymphoid tissues in swine.

Morphologic structures of the lymphoid tissues associated with the mucosa of the respiratory tract in swine aged 11 to 13 weeks were studied by dissecting, light, and transmission electron microscopy. Tissues along the respiratory tract were collected for further examination. Light microscopic examination showed that the lymphoid tissues were associated with bronchi (8.38%), bronchioles (81.63%), and respiratory bronchioles (9.98%). The lymphoid tissues were identified at different levels of the airways and were designated intrapulmonary airway mucosa-associated lymphoid tissues. Anatomically, the lymphoid tissues were found mostly in the bronchiolar bifurcations, with an arteriole frequently nearby. Histologically, the lymphoid tissues contained a single dome-shaped lymphoid follicle, which bulged out from the mucosal surface into the airway, where it was covered along the mucosal side by a layer of specialized epithelium. Ultrastructurally, the mucosal surface of the specialized epithelial cells was equipped with microfolds or cytoplasmic projections instead of cilia. The cytoplasm was elongated, and therefore much thinner than that of ordinary epithelial cells. Many lymphocytes were found scattered in the mucosal epithelium between or beneath the specialized epithelial cells. This structure was similar to that seen in the Peyer's patches of the small intestine in swine and other animals.

Animals↗
PubMed1995

Pathogenic insights from studies of lymphoid tissue from HIV-infected individuals.

Studies of lymphoid tissue from HIV-infected individuals have provided critical insights into the pathogenesis of HIV disease. Systemic dissemination of virus via the lymphatic system occurs at a very early stage after infection. Explosive viral replication within lymphoid tissue ensues, before the development of cell-mediated and humoral immune responses. By the time potent immune responses downregulate viral expression, an immense viral reservoir within lymphoid tissue has already been established. During the stage of dichotomy in viral load between lymph node and peripheral blood, the viral reservoir is maintained by the ability of the follicular dendritic cells (FDC) network to efficiently trap extracellular virions, as well as by immunologic and microenvironmental factors favoring infection of susceptible cells and sequestration of cells already infected. Degeneration of the FDC network and wholesale disruption of lymphoid architecture herald late-stage disease. The dysfunctional lymphoid tissue contributes directly to immunodeficiency and to sharp increases in viral burden and replication as mechanical and immune controls are lost. Studies in HIV-infected long-term nonprogressors indicate that these individuals are able to maintain cell-mediated and humoral immune responses against HIV. These immune responses are responsible, at least in part, for the maintenance of intact lymphoid tissue architecture and the low levels of viral burden and replication detected in these individuals. Studies of the effect of antiretroviral therapy on HIV infection in lymphoid tissue show that decreases in plasma viremia are associated with and most likely are caused by decreases in viral replication within lymphoid tissue. Further understanding of the pathogenic mechanisms within lymphoid tissue will have important implications for early intervention aimed at inducing a long-term nonprogressor state (i.e., preventing disruption of lymphoid tissue integrity), and later intervention aimed at arresting or even reversing damage to the lymphoid system.

Antiviral Agents↗
PubMed2006

Normal structure, function, and histology of mucosa-associated lymphoid tissue.

The mucosa-associated lymphoid tissue (MALT) initiates immune responses to specific antigens encountered along all mucosal surfaces. MALT inductive sites are secondary immune tissues where antigen sampling occurs and immune responses are initiated. Effector sites, present as diffuse lymphoid tissue along all mucosal surfaces are the sites of IgA transport across the mucosal epithelium. Though there are many differences between inductive sites in various organs, they all contain the same basic compartments-follicles, interfollicular regions, subepithelial dome regions, and follicle-associated epithelium. The morphologic differences between MALT and other secondary lymphoid tissues, between the MALT sites of differing anatomic locations, and species differences among laboratory animals are described. The morphologic changes in MALT associated with aging, route of nutrition, and genetic mutation (i.e., the nude and SCID mutations) are also discussed. MALT tissues comprise the mucosal immune system which can function independently of the systemic immune system and are, therefore, an important and often overlooked aspect of immunopathology.

Aging↗
PubMed1995

[Activation of the major omentum-associated lymphoid tissue in Crohn disease].

The mucosa associated lymphoid tissues of the intestinal lamina propria or the bronchial mucosa, respectively, represent a separated and well defined immunologic compartment. Due to highly specialized functions, subpopulations of lymphoid cells are distributed unevenly between the compartments and unique regulatory mechanisms developed to sustain integrity of mucosal surfaces. With this study we investigate whether an omentum associated lymphoid tissue exists and whether it partakes in immunologic processes involved in the perpetuative intestinal inflammation in Crohn's disease. Mononuclear cells from surgically resected omentum tissue (10 patients with Crohn's disease, 10 patients with malignomas or inflammatory control diseases (diverticulitis)) were isolated by collagenase digestion and subsequent serial density centrifugation. Phenotypic analysis was carried out by immunofluorescent labeling with a panel of monoclonal antibodies as well as peanut agglutinin. Most interestingly, the percentage of CD4-T(Helper) cells among omentum mononuclear cells was decreased in comparison with peripheral blood mononuclear cells, whereas the percentage of monocytes/macrophages and of natural killer cells appeared to be increased. In comparison with normal peripheral blood a higher percentage of normal omentum mononuclear cells were activated. It thus appears that a defined immunologic compartment exists which is different in its cellular composition from peripheral blood as well as from intestinal mucosa associated lymphoid tissue and which may be called omentum associated lymphoid tissue. In Crohn's disease subpopulations of omentum mononuclear cells did not change in number, however immunologic activation increased further and appears to be highly increased in comparison to both omentum cells from disease specificity controls (diverticulitis) and Crohn's disease peripheral blood cells. We conclude that omentum associated lymphoid tissue may be described as an unique immunologic compartment which may play a role in activating events in chronic intestinal inflammation in Crohn's disease. Further studies will address functional characteristics of the omentum associated lymphoid tissue and will investigate regulatory mechanisms which may contribute to the inflammatory process in Crohn's disease.

Adult↗
PubMed2005

Bronchus- and nasal-associated lymphoid tissues.

The bronchus-associated lymphoid tissue (BALT) and the nasal-associated lymphoid tissue (NALT) constitute organized lymphoid aggregates that are capable of T- and B-cell responses to inhaled antigens. BALT, located mostly at bifurcations of the bronchus in animals and humans, is present in the fetus and develops rapidly following birth, especially in the presence of antigens. Humoral immune responses elicited by BALT are primarily immunoglobulin A secretion both locally and by BALT-derived B cells that have trafficked to distant mucosal sites. Similarly located T-cell responses have been noted. On the basis of these findings, the BALT can be thought of as functionally analogous to mucosal lymphoid aggregates in the intestine and is deemed a member of the common mucosal immunologic system. NALT has been described principally in the rodent nasal passage as two separate lymphoid aggregates. It develops after birth, likely in response to antigen, and B- and T-cell responses parallel those that occur in BALT. It is not known whether NALT cells traffic to distant mucosal sites, although mucosal responses have been detected after nasal immunization. NALT appears from many studies to be a functionally distinct lymphoid aggregate when compared with BALT and Peyer's patches. It may exist, however, in humans as a diffuse collection of isolated lymphoid follicles.

Animals↗
PubMed1984

Heterogeneity of macrophage populations in human lymphoid tissue and peripheral blood.

Human lymphoid tissue and peripheral blood leukocytes were stained with six monoclonal antibodies directed against monocyte/macrophage populations. The staining pattern described by each of these monoclonal reagents was compared with the distribution of morphologically distinguishable tissue macrophages. The results show that there exists considerable heterogeneity of tissue macrophages based on the expression of surface and/or cytoplasmic antigens; furthermore, the distribution of cells bearing particular antigenic determinants is associated with distinct regions in normal lymphoid tissue. Double staining methods demonstrated that these antibodies bind to different, as well as to identical, macrophage populations. OKM-1 antibody binds predominantly to sinus histiocytes and tingible body macrophages. The Leu M-1 reagent stains interdigitating reticulum cells, while the KiM-4 antibody labels follicular dendritic cells. Leu M-3 antibody identifies cells predominantly in the germinal center, and histiocytes lining the sinuses. Both CM-1 and BRL-M.1 appear to stain tissue macrophages distributed throughout the lymphoid tissue.

Antibodies, Monoclonal↗
PubMed2002

Immunohistochemistry of the lymphoid tissues of the tammar wallaby, Macropus eugenii.

The lymphoid tissues of the metatherian mammal, the adult tammar wallaby, Macropus eugenii, were investigated using immunohistochemical techniques. Five cross-reactive antibodies previously shown to recognize surface markers in marsupial tissues and five previously untested antibodies were used. The distribution of T-cells in the tissue beds of spleen, lymph node, thymus, gut-associated lymphoid tissue (GALT) and bronchus-associated lymphoid tissue (BALT) was documented using antibodies to CD3 and CD5. Similarly, B-cells were identified in the same tissues using anti-CD79b. Antibodies to CD8, CD31, CD79a and CD68 failed to recognize cells in these tissue beds. In general the pattern of cellular distribution identified using these antibodies was similar to that observed in other marsupial and eutherian lymphoid tissues. This study provides further information on the commonality of lymphoid tissue structure in the two major groups of extant mammals, metatherians and eutherians.

Animals↗
PubMed1986

Immunohistochemical analysis of human peripheral blood and lymphoid tissues using monoclonal antibodies immunoreactive with non-lymphoid cells.

Immunoperoxidase methods were used to study human peripheral blood and lymphoid tissues using a panel of monoclonal antibodies to non-lymphoid cells. The majority of peripheral blood monocytes were immunoreactive for LeuM1, LeuM2, LeuM3 and LeuM5. Rare peripheral blood monocytes were immunoreactive for R4/23. The different antibodies showed characteristic patterns of immunoreactivity in peripheral lymphoid tissues. LeuM1 was immunoreactive with scattered cells in the paracortex of lymph node and tonsil and with many cells in the marginal zone of the spleen. LeuM2 was immunoreactive with endothelial cells in lymph node and tonsil. A few cells in the red pulp of the spleen were immunoreactive for LeuM2. LeuM3 and R4/23 showed distinctive immunoreactivity in germinal centers of secondary follicles, giving a "lacy" pattern. LeuM3 was also immunoreactive with endothelium in lymph node and tonsil and with sinus lining cells in lymph node. LeuM5 was immunoreactive with macrophages in the germinal center, fibroblastic reticulum cells in the mantle zone and interdigitating reticulum cells in the paracortex of lymph node and tonsil.

Antibodies, Monoclonal↗
PubMed2003

Development of lymphoid tissues of the stripe-faced dunnart (Sminthopsis macroura).

The development of the lymphoid tissues of a model marsupial, the stripe-faced dunnart, has been described from birth to weaning, a period of 2.5 months. At birth the lymphoid tissues, including the thymus, lymph nodes and mucosa-associated lymphoid tissues, were undeveloped. A thoracic thymus consisting primarily of stromal tissue was observed by day 4 after birth but by day 12, lymphocytes were observed in the thymus and some cortico-medullary differentiation was apparent. Lymph nodes were histologically mature by day 31, the earliest day investigated for this tissue. In gut tissue, lymphoid follicles were first observed by day 57 post-partum. No bronchus-associated lymphoid tissue was observed in any lung samples. The thymus, lymph nodes and gut-associated lymphoid tissues were all distinguishable before weaning (day 70) but not all were histologically mature. The sequence of development of the lymphoid tissues in the stripe-faced dunnart was similar to those observed in other marsupial species.

Adipose Tissue↗
PubMed2007

Role of Helicobacter pylori in conjunctival mucosa-associated lymphoid tissue lymphoma.

OBJECTIVE: Conjunctiva-associated lymphoid tissue is the conjunctival equivalent to mucosa-associated lymphoid tissue (MALT). Mucosa-associated lymphoid tissue lymphoma has been shown to be associated with Helicobacter pylori. In this study, the prevalence and possible role of H. pylori infection in conjunctival MALT lymphoma were evaluated. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Thirteen cases of conjunctival MALT lymphoma were investigated. Five samples of conjunctival lymphoid hyperplasia and 20 biopsies of normal conjunctiva served as controls. METHODS: The specimens were investigated for the presence of H. pylori with immunohistochemistry (IHC) and nested polymerase chain reaction (PCR) techniques. For each case of conjunctival MALT lymphoma, information regarding gender, age at presentation, conjunctival localization, and information of generalized MALT lymphoma were collected. MAIN OUTCOME MEASURES: Detection of H. pylori and patient characteristics. RESULTS: The 13 conjunctival MALT lymphomas originated from 8 women and 5 men with an average age of 62 years (range, 25-87). Only 1 patient had evidence of systemic MALT lymphoma. H. pylori could not be identified in any of the conjunctival MALT lymphomas, in conjunctival lymphoid hyperplasia, or in normal conjunctival biopsies using IHC and PCR techniques. CONCLUSIONS: An association between H. pylori and localized conjunctival MALT lymphoma could not be verified. Antigens other than H. pylori may take part in the development of conjunctival MALT lymphoma.

Adult↗