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At least 649 records · Page 36Linked to original sources
PubMed1986

Effects of a perfluorocarbon emulsion, Fluosol-DA, on rat lymphoid tissue and immunological competence.

The effects of administration of low doses (5 or 10 ml/kg body wt) of the proprietary perfluorocarbon emulsion blood substitute, Fluosol-DA 20%, on rat lymphoid tissue and antibody production against sheep red blood cells (SRBC) have been studied. Spleen and mesenteric lymph nodes (MLN) were significantly heavier at eight days after injection of Fluosol, whereas liver and thymus weights were unchanged. The mean plasma antibody titre to sheep red blood cells was significantly (P less than 0.05) increased in animals injected intraperitoneally with both doses of Fluosol-DA before immunization. These results show that there are differences in the uptake of perfluorochemicals by certain rat lymphoid tissues and that immunological competence can be altered following administration of such materials.

Animals↗
PubMed2001

Ischemia-induced neuronal expression of the microglia attracting chemokine Secondary Lymphoid-tissue Chemokine (SLC).

Recently, it has been demonstrated that Secondary Lymphoid-tissue Chemokine (SLC) is constitutively expressed in secondary lymphoid organs and controls the homing of naive T-cells and mature dendritic cells. By screening cDNA isolated from ischemic mouse brain, we found expression of SLC mRNA 6 h up to 4 days after the onset of ischemia. In situ hybridization combined with immunohistochemistry showed neurons expressing SLC mRNA in the ischemic area of the cortex. SLC mRNA expression was also found in cultured neurones after various treatments known to induce neuronal death, but not in cultured glial cells. Stimulation with SLC induced intracellular calcium transients and chemotaxis in cultured microglia. Since mRNA encoding CXCR3, an alternative receptor for SLC, but no CCR7 mRNA was found in microglia, we suggest that the effects of SLC on microglia are mediated by CXCR3. This assumption was corroborated by cross-desensitization experiments using IP-10 as a ligand for CXCR3. The inducible expression of SLC in neurones acting on microglia suggests a new and important role of SLC in the neuroimmune system. We propose that SLC is part of a neurone-microglia signaling system which is related to pathological conditions of the brain like ischemia.

Animals↗
PubMed2002

MUC1 mucin expression in follicular dendritic cells and lymphoepithelial lesions of gastric mucosa-associated lymphoid tissue lymphoma.

Membrane-associated mucin MUC1 is expressed in various adenocarcinoma cells and active T lymphocytes. We tried to find out whether MUC1 is expressed in gastric mucosa-associated lymphoid tissue (MALT) lymphoma lesion. MUC1 was not expressed in infiltrating T lymphocytes; however, MUC1 was found on the cell surface of follicular dendritic cells (FDC) of germinal centers and in the epithelial cytoplasm of lymphoepithelial lesion (LEL) of the lymphoma, which were immunohistochemically detected by monoclonal antibodies DF3 and MY.1E12. MUC1 was also expressed in the FDC of control cases (gastrectomy specimen containing reactive lymphoid follicles, n = 10, MUC1/ DF3, 100%; MUC1/MY.1E12, 40%), and FDC in MALT lymphomas (n = 59) showed lower MUC1 expression rates (MUC1/ DF3, 32%; MUC1/MY.1E12, 0%) than the control (P < 0.001). Lymphoepithelial lesion in the low-grade MALT lymphomas (n = 23) showed a higher MUC1/DF3 expression rate (30%) than those in the high-grade MALT lymphomas (n = 36; 6%; P < 0.05). T lymphocytes in the surface mucosa were more frequent in MALT lymphoma (91.4 +/- 80.6/unit area) than those in the control (20.0 +/- 23.6) (P < 0.001). S100-positive dendritic cells around LEL were more frequent in the low-grade (19.0 +/- 9.4/unit area) than in the high-grade (11.7 +/- 9.7) (P < 0.005). This study demonstrated MUC1 mucin expression on FDC for the first time. Mucosa-associated lymphoid tissue lymphoma, especially low-grade, shows immunologically active state, where FDC MUC1 expression may be suppressed by some factors released from lymphoma cells. Further study to elucidate the pathogenetic role of MUC1 in MALT lymphoma is necessary.

Aged↗
PubMed1995

The B-cell response in lymphoid tissue of mice immunized with various antigenic forms of the influenza virus hemagglutinin.

Protection of BALB/c (H-2d) mice against secondary challenge with influenza A viruses is primarily dependent on appropriate recognition of the hemagglutinin (HA) molecule by effectors of humoral immunity, the B lymphocytes and their product the immunoglobulin molecules. The influence of the antigenic form of the HA in eliciting protective antibodies is not clearly defined. We directly monitored the kinetics, character, localization, and helper T-cell dependence of the primary antibody-forming cell (AFC) response and the development of B-cell memory in lymphoid tissues associated with the upper and lower respiratory tracts, and in the spleen and bone marrow, to three forms of HA with various degrees of antigenic organization. Our results show that the antigenic organization of HA substantially influences B-cell immunity, namely, the capacity to generate both primary AFCs and memory B cells responsive to lethal challenge. Immunization by infection is the most efficient means of generating protective memory B cells, in contrast to subunit vaccine. The data also indicate that memory AFCs are predominantly localized to the regional lymphoid tissue where challenge HA is found, unlike primary AFCs, which are restricted to the priming site and which require in vivo CD4+ T-cell help.

Animals↗
PubMed2000

A bone marrow-derived APC in the gut-associated lymphoid tissue captures oral antigens and presents them to both CD4+ and CD8+ T cells.

We have previously reported that feeding OVA to C57BL/6 mice can lead to a weak CTL response that is dependent on CD4+ T cell help and is capable of causing autoimmunity. In this study, we investigated the basis of the class I and class II-restricted Ag presentation required for such CTL induction. Two days after feeding OVA, Ag-specific CD4+ and CD8+ T cells were seen to proliferate in the Peyer's patches and mesenteric lymph nodes. Little proliferation was evident in other lymphoid tissues, except at high Ags doses, in which case some dividing CD4+ T cells were observed in the spleen and peripheral lymph nodes. Using chimeric mice, the APC responsible for presenting orally derived Ags was shown to be derived from the bone marrow. Examination of the Ag dose required to activate either CD4+ or CD8+ T cells indicated that a single dose of 6 mg OVA was the minimum dose that consistently stimulated either T cell subset. These data indicate that oral Ags can be transported from the gut into the gut-associated lymphoid tissue, where they are captured by a bone marrow-derived APC and presented to both CD4+ and CD8+ T cells.

Administration, Oral↗
PubMed1992

Complement activation in the follicular light zone of human lymphoid tissues.

A comparative immunohistochemical study of the distribution pattern of complement components and regulatory proteins within secondary lymphoid follicles was performed by the immunoperoxidase technique. Fifteen lymphoid tissues including appendices. Peyer's patches and tonsils were analysed. Sixty secondary lymphoid follicles with evident polarity, that is, the distinct coexistence of a light zone, dark zone and mantle zone in the same lymphoid follicle, were tested with single antibodies. The light zones were consistently immunostained in a dendritic meshwork pattern with all antibodies. The immunostaining patterns were classified into two major groups based on the immunoreactivity of the dark zone. One immunostaining pattern was characterized by no immunostaining of the dark zone to the majority of the antigens. The second group was characterized by a diffusely weak to moderate dendritic meshwork pattern of the dark zone to some of the immunostainings of C9 (monoclonal), S-protein, and DF-DRC1, and all immunostainings of CR1 (CD35), Ber-Mac-DRC (CD35), CR2 (CD21), and R4/23. All four complement regulatory proteins were localized by immunoelectron microscopy attached to the cell surface of the cells, including follicular dendritic cells, in the light zone. Our data indicate that there is an evident functional difference between the light zone and the dark zone, and that complete activation of the complement system occurs only in the light zone.

Antigens, Differentiation, B-Lymphocyte↗
PubMed2003

[Bronchial-associated lymphoid tissue lymphoma].

Two cases of non-Hodgkin's endobronchial or bronchial-associated lymphoid tissue lymphoma are reported; such cases are either extremely rare or underestimated. We emphasize the need to perform endoscopic examination in patients with lymphoma and clinical findings that suggest bronchial disease.

Aged↗
PubMed1996

Phenotypic classification of porcine lymphocyte subpopulations in blood and lymphoid tissues.

The pig is a useful model for the heterogeneity of the mammalian immune system and has also recently received attention as a possible source of organs for human transplantation. Here we report a detailed analysis of porcine lymphocyte phenotypes. Peripheral blood alpha beta T cells consisted of four subsets (CD4+8-, CD4+8lo, CD4-8lo and CD4-8hi) and gamma delta T cells of three (CD2-4-8-, CD2+4-8lo and CD2+4-8-). There were in addition, a large proportion of non-T-non-B lymphocytes with CD2+3-4-8lo surface immunoglobulin-negative phenotype containing natural killer (NK) activity. A striking observation was the relatively low frequency of alpha beta T cells in the blood of young pigs. Similar phenotypes were also identified in the cells from peripheral lymphoid tissues, though the proportions of the gamma delta T cells and the non-T-non-B lymphocytes in the lymph nodes and tonsil were much lower and the majority of the gamma delta T cells in the lymphoid tissues bore CD2 and or CD8. In thymus, the small thymocytes were predominantly CD3-4+8+ while the mature large thymocytes displayed phenotypes similar to those of peripheral T cells. Thus this work has directly defined porcine alpha beta and gamma delta T cells demonstrated the T-cell nature of the unique CD4+8+ subset of peripheral lymphocytes, revealed the high heterogeneity of the CD8+ cells, and established the phenotype of NK cells. The functional properties of these defined porcine lymphocyte subsets can now be experimentally determined in health and disease.

Animals↗
PubMed1982

IgA-producing hybridomas are readily derived from gut-associated lymphoid tissue.

Eight hybridomas secreting IgA monoclonal antibodies were obtained by using gut-associated lymphoid tissue as a primed plasmablast source. IgA secretors are obtained at higher frequencies by this technique than by conventional splenic fusions. This technique provides useful tools for the study of mucosal protection, and it demonstrates that exaggerated potential of gut-derived B cells, compared to splenic B cells, for IgA expression.

Animals↗
PubMed1985

Weight reduction of thymus and depletion of lymphocytes of T-dependent areas in peripheral lymphoid tissues of mice infected with Francisella tularensis.

When BALB/c mice (young and adult animals of both sexes) were infected intraperitoneally with 10(3) viable cells of Francisella tularensis (10(2) 50% lethal dose), all mice in these groups died on day 4. Reductions in thymus weights and in numbers of thymic cortex lymphocytes were observed in all the groups, but the decline was not so severe in the young females. Increases of plasma corticosterone in the adult males began 1 day after infection, but in the young females, the levels did not increase until day 3, the same days on which the respective thymus weights began to decline. Depletion of the thymus weights in the infected mice was prevented by adrenalectomy. The lymphocytes of the thymus (T)-dependent areas in peripheral lymphoid tissues in all groups were destroyed. By using an electron microscope, we found a large quantity of F. tularensis within the macrophages in the T-dependent areas but not in the thymus. The destruction of lymphocytes in the T-dependent areas was not prevented by adrenalectomy. Therefore, it was concluded that the weight reduction of the thymus is due to the stress of the F. tularensis infection. However, we think other mechanisms are responsible for the depression of lymphocytes in the T-dependent areas of peripheral lymphoid tissues.

Adrenalectomy↗
PubMed2003

Gastric mucosa-associated lymphoid tissue lymphoma.

The connection between Helicobacter pylori and gastric mucosa-associated lymphoid tissue (MALT) lymphoma is well established. H. pylori infection causes an immunological response, leading to chronic gastritis with formation of lymphoid follicles within the stomach. These lymphoid follicles resemble nodal tissues found throughout the body and are composed of reactive T cells and activated plasmal cells and B cells. The B cells are responsible for initiating a clonal expansion of centrocyte-like cells that form the basic histology of MALT lymphoma. Early diagnosis of MALT lymphoma is difficult but essential for adequate treatment. Clinical symptoms are vague and varied, with abdominal pain being a common presenting complaint. The endoscopic appearance of this tumor is varied and can be infiltrative, exophytic, or ulcerative. In addition, the tumor can have a multifocal distribution, and therefore aggressive tissue sampling is crucial for diagnosis. Endoscopic ultrasound is essential to document the extent of disease and is more accurate than CT scan in detection of spread to perigastric lymph nodes. Lesions that are confined to the mucosa or submucosa of the gastric wall are believed to be dependent on H. pylori stimulation and therefore can be successfully treated with H. pylori eradication. Those MALT lymphomas that present at more advanced stages require more aggressive management and can be treated with surgical resection, radiation, or chemotherapy. Follow-up is critical in all patients who have been treated with H. pylori eradication and consists of multiple endoscopic biopsies for histological and molecular studies as well as endoscopic ultrasound at 3, 6, and 12 months after treatment. The reappearance of MALT lymphomas has been seen years after treatment, and therefore follow-up of these patients should be indefinite.

Anti-Bacterial Agents↗
PubMed2005

Dopamine nerve fibres and related receptors in bronchus-associated lymphoid tissue (BALT).

Age-related changes of the dopamine nerve fibres of bronchus associated lymphoid tissue (BALT) were investigated in male Wistar rats of 3 months (young), and 24 months (old/aged). Dopamine histofluorescence techniques have been used, associated with image analysis for the detection of dopamine nerve fibres. In young rats, white, fluorescent nerve fibres supply BALT. This tissue is innervated by a delicate network of nerve fibres rich in varicosities. In old rats these fluorescent nerve fibres are strongly reduced. Moreover, dopamine D1a and D1b receptors were stained using fluorescent monoclonal antibodies. The BALT of young rats possesses a higher number of D1a and D1b receptors, while, in the old rats, these receptors are strongly reduced. The possible significance of reduced dopamine neurotransmission in BALT of aged rats is discussed.

Aging↗
PubMed2006

Primary breast mucosa-associated lymphoid tissue (MALT) lymphoma with high-grade transformation evidenced by prominent lymphoepithelial lesions.

Primary breast lymphoma, particularly primary mucosa-associated lymphoid tissue (MALT) lymphoma, is a rare disease. We report here a case of a MALT lymphoma of the breast with high-grade transformation. An 84-year-old woman presented with a Pagetoid mass in her right breast. After a clinical diagnosis of breast cancer, T2N1M0, stage II B, she underwent mastectomy with axillary lymph node dissection. She had no history of autoimmune disease such as Hashimoto thyroiditis or Sjögren disease. Pathologically the tumor tissue was composed of small to large lymphoid cells. The large cells contained a considerable number of centroblasts, forming a sheet-like proliferation centrally. Among the small cells many small cleaved cells were present, which were more predominant in the peripheral areas. Immunohistochemistry revealed that these cells were positive for CD20 and CD79a. The tumor cells infiltrated the ductular epithelial cells, distorting the duct structures, to form lymphoepithelial lesions. Immunohistochemistry for cytokeratin and CD20 was helpful for identification. No germinal centers were formed. MALT lymphoma with high-grade transformation was diagnosed. Rituximab (anti-CD20 antibody) was prescribed as systemic treatment without chemotherapy or irradiation. After 18 months, no tumor recurrence was observed. We emphasize the importance of lymphoepithelial lesions for the diagnosis of MALT lymphoma of the breast.

Aged↗
PubMed2004

A human CR1-like transcript containing sequence for a binding protein for iC4 is expressed in hematopoietic and fetal lymphoid tissue.

Primate immune adherence receptors are erythrocyte complement receptors (E-CR) that favorably influence the clearance of circulating immune complexes (IC). The human E-CR is the type one complement receptor (CR1), most commonly expressed as a 220 kDa protein containing 30 short consensus repeats (SCRs). The chimpanzee E-CR is a 75 kDa protein composed of eight SCRs, and is encoded by an ortholog of human CR1-like (CR1L), a genetic element related to CR1. Human CR1L was previously identified from genomic clones that predict exons for seven SCRs, and there have been no reports of CR1L expression. The purpose of this study was to determine if human CR1L is expressed. Amplification of human bone marrow cDNA using primers specific for CR1/CR1L yielded a product similar to chimp CR1L encoding sequence. The first 6.5 SCRs matched 100% with the predicted human CR1L sequence, while the second half of SCR 7 was homologous to the comparable chimp CR1L sequence but with a stop codon. Expression in COS-7 cells yielded a human CR1L protein of approximately 50 kDa that exhibited binding specificity for iC4 but not for iC3. Neither northern nor western blot analysis of human bone marrow revealed the presence of the CR1L transcript or protein. However, northern blot analysis of various other lymphoid tissue identified a candidate CR1L transcript in human fetal liver. PCR amplification of a cDNA panel of human fetal tissue confirmed the presence of the CR1L transcript in fetal liver, and to a lesser extent in fetal spleen and thymus. Thus, expression of the CR1L transcript appears to be limited to hematopoietic and fetal lymphoid tissue.

Amino Acid Sequence↗
PubMed1992

t(11;18)(q21;q21.1): a recurring translocation in lymphomas of mucosa-associated lymphoid tissue (MALT)?

A distinct subtype of extranodal malignant lymphoma derived from mucosa-associated lymphoid tissues (MALT) has recently been defined. We have detected an acquired t(11;18)(q21;q21.1) in a patient with a MALT lymphoma of the stomach. This translocation has previously been described in two other patients with extranodal lymphoma. The BCL2 oncogene, which is located at band 18q21.3 and is activated by the t(14;18)(q32;q21) in follicular lymphoma, was not rearranged in this case. This newly identified t(11;18) may be a recurring translocation specifically associated with MALT lymphomas. Genes located at the breakpoint sites of chromosome 11 and/or chromosome 18 may be crucial to the pathogenesis of this type of malignant lymphoma.

Base Sequence↗
PubMed1981

Fibroblastic and dendritic reticulum cells of lymphoid tissue. Ultrastructural, histochemical, and 3H-thymidine labeling studies.

Fibroblastic reticulum cells of different lymphoid organs were investigated to clarify their relationship to other stationary cells of the lymphoid tissue and to fibroblasts of the connective tissue. Fibroblastic reticulum cells have many ultrastructural characteristics of fibroblasts but differ from them in containing prominent bundles of microfilaments and in reacting strongly with antibodies to smooth muscle type myosin and actin. The fibroblastic reticulum cell may be thus classified as a myofibroblast. Enzyme-histochemical studies showed that fibroblastic reticulum cells contain a definite alkaline phosphatase isoenzyme. During ontogeny fibroblastic and dendritic reticulum cells are derived from the local mesenchyme and may be considered as primary stationary reticulum cells. During the formation of the follicle in the splenic white pulp in young rats fibroblastic and dendritic reticulum cells show a different turnover which speaks in favor of a proliferation of dendritic reticulum cells or their precursors in follicle formation.

Alkaline Phosphatase↗
PubMed1992

[Immunoresponses to the external antigen in conjunctival-associated lymphoid tissue].

The local immunity of the ocular surface is governed by conjunctival-associated lymphoid tissue (CALT), secretory IgA and immunocytes. The authors performed a histological investigation of the time-course changes in CALT caused by invasion of antigen to the ocular surface through the instillation of horseradish peroxidase (HRP) into the guinea pig eye. We used PAS staining, peroxidase staining, alkaline phosphatase staining. The lymphoepithelial cells of CALT phagocytized HRP 30-60 min after the instillation, and formed intraepithelial pockets 24 hours after instillation. The follicular area of CALT was strongly positive for alkaline phosphatase 2 weeks after instillation. These changes were considered to be the first step in the manifestation of local immunity on the ocular surface. Each staining technique revealed differences between the lymphoepithelium and conjunctival epithelium, suggesting that lymphoepithelium has characteristics different from those of conjunctival epithelium.

Animals↗