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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anti-idiotypic antibodies were prepared in (CBA X C57BL/6)F1 hybrid mice by immunization either with CBA anti-C57BL/6 alloantiserum or with purified CBA thymus-processed lymphoid cells (T cells) Iodinated anti-mouse Ig or triple sandwich ferritin-labeling techniques served to visualize the reaction between idiotype and anti-idiotype. From 5 to 10% of purified CBA T cells appeared to carry receptors for C57BL/6 antigens. Heavily labeled cells had the morphology of small lymphocytes.
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PMID:Idiotype positive T cells visualized by autoradiography and electron microscopy. 108 Dec 29

The fine structure of human appendix was studied from the earliest stages of lymphoid development in fetuses to the definitive relationships found in children up to 8 years old. Follicular accumulations of lymphocytes were observed first in the mesenchyme immediately beneath epithelium which contained a predominance of goblet cells on the surface and in the crypts. Larger accumulations of lymphoid cells in older fetuses were intimately related to surface epithelium but not to the epithelium of crypts. At the point of invasion of lymphoid cells into surface epithelium, the goblet cell population diminished and epithelial cells displaying a morphologically distinct form of differentiation were observed. They were characterized by the presence of irregular microvilli or microfolds and numerous apical micropinocytotic vesciles. This follicle-associated epithelium (FAE) appeared ultrastructurally identical with epithelium in chicken bursa of Fabricius, mouse Peyer's patch, and rabbit appendix, which has been shown to be capable of transporting ferritin and India ink tracer from the lumen to underlying tissue. It appeared identical to specialized epithelial cells of adult human Peyer's patches. FAE was maintained through the neonatal period into childhood. We speculate that the biological significance of FAE is to provide a channel through which antigens may stimulate clonal proliferation and seeding of B-lymphocytes throughout the lamina propria of internal mucous surfaces.
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PMID:Early lymphoepithelial relationships in human appendix. A combined light- and electron-microscopic study. 112 95

We have previously demonstrated that distinct binding sites exist for human recombinant H ferritin (HrHF) and human liver ferritin (HLF) on human T lymphoid cells (MOLT-4). This study demonstrates that these binding sites have the characteristics of receptors specific for HrHF, and the binding characteristics and internalization of HrHF to MOLT-4 cells have now been examined. Iodinated HrHF was displaced by an excess of unlabeled HrHF. Heavy ferritin was the major subunit bound with only a small amount of light-ferritin binding, consistent with our immunofluorescence studies. Scatchard plot analysis of the competitive binding data for HrHF revealed an association constant of 6.3 to 6.7 x 10(7) L/mol with approximately 6000 to 15,000 receptor sites per MOLT-4 cell. Internalization of HrHF was demonstrated with pronase. Chloroquine substantially reduced the uptake of HrHF. Release of internalized HrHF was not observed when cells were rewarmed to 37 degrees C. These results indicate that HrHF is internalized by a mechanism consistent with receptor-mediated endocytosis, with possible involvement of the lysosome. The internalized HrHF remains associated with the cell. Although lymphoid cell growth and differentiation were not examined in this study, the presence of the demonstrated receptors may indicate a regulatory role for heavy ferritin in such cells.
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PMID:Characterization of the ferritin receptors of human T lymphoid (MOLT-4) cells. 131 40

We have previously demonstrated the presence of receptors specific for human recombinant H ferritin (HrHF) on human T lymphoid cells (MOLT-4), and changes in receptor number and binding affinity with growth and cell cycling have now been examined. Specific binding of HrHF was maximal in MOLT-4 cells harvested during exponential growth with the cells in the DNA synthesis phase of the cell cycle. Specific binding decreased progressively to the plateau phase of growth with the cells in the resting phase of the cell cycle. Scatchard analysis of the competitive binding data for HrHF demonstrated that this decrease in binding was associated with a reduction in receptor number, from 42,140 per cell to 10,306 per cell. Receptor binding affinity increased only minimally over this period, from 7.1 x 10(7) L/mol to 14.9 x 10(7) L/mol. These results indicate that growth- and cell cycle-induced changes in H-ferritin receptor expression are primarily associated with changes in receptor number rather than receptor binding affinity. The present study demonstrates that the expression of this receptor is associated with the proliferative status of the cell and suggests that the H-ferritin receptor may mediate the putative regulatory role of H-ferritin.
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PMID:Effect of cell proliferation on H-ferritin receptor expression in human T lymphoid (MOLT-4) cells. 132 34

We used lipopolysaccharide (LPS) to provoke immune responses and observed the changes in the localization of iron and iron-related proteins, such as transferrin receptor, ferritin and hemosiderin in the rat spleen. After intravenous injection of 250 micrograms LPS (salmonella minnesota R595), spleen weight and serum IgM levels increased, cells incorporating 5-bromo-2'-deoxyuridine (BrdU), and transferrin receptor positive cells increased in the peripheral portion of the periarterial lymphoid sheath (PALS), the marginal zone (MZ) and the follicles. Ferritin positive cells increased markedly in the white pulp and stainable iron increased in the marginal metallophils (MM) and in the macrophages in the MZ and the outer PALS. Even in iron deficient rats, a similar change was observed for the localization of iron and iron-related proteins after injection of LPS. After injection of 0.4 mg keyhole limpet hemocyanin (KLH), changes similar to but less pronounced than that in the LPS injected rats were observed for serum IgM levels and for the localization of iron and iron-related proteins. These results showed that the iron in the MM and the macrophages in the white pulp have a dynamic response to immunological challenges and suggested that they play some role in immune responses.
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PMID:Mobilization of iron and iron-related proteins in rat spleen after intravenous injection of lipopolysaccharides (LPS). 144 84

Transfer factor activities have been studied in both clinical and basic science settings for several decades. Until now, highly purified transfer factors that are suitable for molecular analysis have not been available. This has impeded progress towards understanding the molecular and cellular basis of the activities of these important inducers of cell-mediated immune responses. Murine transfer factors with specificities for chicken egg albumin or horse spleen ferritin were purified to virtual homogeneity using a combination of affinity chromatography and reversed-phase and polytypic high performance liquid chromatography (hplc). Transfer factors prepared by this methodology were recovered in high yield and in biologically-active, antigen-specific forms. The purified materials were further analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis, chromatographic methods and an in vivo assay for immunological activity. For the first time definitions for unit transfer factor activity and specific activity are introduced. The results of these experiments indicate that transfer factors are a family of highly polar, hydrophilic molecules of low molecular weight (approximately 5,000) which are produced in small quantities by lymphoid cells and which have potent biological activity. The availability of purified transfer factors should facilitate definitive studies into the nature and mechanisms of production and action of these molecules.
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PMID:Purification of transfer factors. 154 96

A retrospective study of the 99 surviving heart and lung transplant (HLT) recipients at one center showed that 31% had significant anemia (hemoglobin less than 100g/L) six months after transplantation. Chronic anemia persisted in 18% of HLT recipients two years posttransplantation. A similar study of 100 heart transplant recipients showed no unexplained anemic patients. The prevalence of anemia after HLT was unrelated to the original diagnosis, immunosuppression, or acute rejection. All HLT recipients appeared to be unduly sensitive to the myelosuppressive effects of azathioprine. Detailed studies in 16 representative patients showed a normochromic, anisocytotic anemia with normal reticulocyte counts, B12 and folate levels, and haptoglobin levels and appropriate erythropoietin levels--but increased ESRs, low/normal iron levels and low/normal total iron binding capacity, normal or raised ferritin levels, and autoantibodies in 4 (25%). Bone marrow aspirates in 10 patients showed dyshemopoiesis out of proportion to the degree of anemia and colonies of activated lymphoid cells. The cause for this anemia appears to be a combination of anemia of chronic disease and dyshemopoiesis, both of uncertain etiology.
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PMID:The prevalence, course, and characteristics of chronic anemia after heart and lung transplantation. 160 80

Uptake of macromolecules (e.g., ferritin) by M cells in follicle-associated epithelium in small and large intestine was investigated in three healthy, conventionally raised, 2- to 3-week-old, female Holstein Frisian calves. A 2.5% solution of ferritin was injected into the ligated loops in mid-jejunum, in terminal ileum, in the ascending colon adjacent to the ileocecal junction, and in the proximal loop of the ascending colon containing gut-associated lymphoid tissue. After exposure times that ranged from 82 to 165 minutes, ferritin was detected in M cells of domes in the small intestine, as well as in cells in follicle-associated epithelium of proprial lymphoid nodules and lymphoglandular complexes of colon that morphologically resembled M cells of small intestine. Ferritin was found in apical invaginations, apical vesicles, multivesicular bodies, basal vesicles, and adjacent intercellular spaces. In addition to ferritin, apical vesicles, multivesicular bodies, and intercellular spaces contained 50-nm membrane-bound particles. More ferritin was endocytosed by M cells of the small intestine than by M cells of the large intestine. In the large intestine, higher amounts of ferritin were found in M cells of follicle-associated epithelium overlying proprial lymphoid nodules than in M cells of follicle-associated epithelium in the depth of lymphoglandular complexes. Based on these results, we concluded that M cells of follicle-associated epithelium in the colon of calves provide a route for antigen uptake into the intestinal lymphoid system.
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PMID:Uptake of ferritin by follicle-associated epithelium in the colon of calves. 163 55

Ultrastructural, flow cytometric, and molecular studies were performed on leukemia cells from bone marrow and pleural effusion of a 6-year-old boy diagnosed with undifferentiated (MO) leukemia, using routine histology and immunostains at diagnosis and relapse. Ultrastructurally, surface and/or intracellular ferritin particles were present on or in some blasts and the majority of blasts contained identifiable acid ferrocyanide reactive inorganic iron comparable to that seen in normal early erythroblasts. The cells lacked other evidence of differentiation, including diaminobenzidine-reactive or immunoreactive hemoglobin. Flow cytometric analysis of malignant cells showed a lack of lymphoid or myeloid markers. Anti-transferrin receptor antibody was positive on 93% of cells and antibody to glycophorin A reacted with 23% of cells. RNA blot analysis of leukemia cells with myeloperoxidase (MPO) showed an absence of appreciable levels of MPO mRNA. Chromosome analysis showed 51,XY, t(1;16)(p31;q24), +6, +10, +15, +19, +21. The oncogene c-myb, which is specifically expressed and regulated in hematopoietic cells and produces a DNA-binding protein responsible for myeloid differentiation, was found to be duplicated in the patient's tumor cells. Expression of c-jun, N-ras, c-myc, and p53 was normal. The data indicate that the malignant cells in this patient are of early erythroid lineage at diagnosis and relapse and that classification of cell lineage can be enhanced by ultrastructural Prussian blue staining. The failure of this otherwise undifferentiated leukemia to express or evolve into a myeloid phenotype is biologically and clinically distinct from previously described cases of erythroid and myeloid leukemia and may represent a previously unidentified phenotype which should be included in the spectrum of 'undifferentiated' childhood leukemia.
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PMID:Childhood undifferentiated leukemia with early erythroid markers and c-myb duplication. 170 34

The morphology of gut-associated lymphoid tissue and the ultrastructure of overlying lymphoepithelium of newborn and three-week-old conventionally raised calves were compared. In all calves patches of lymphoid nodules were found in the terminal rectum. In newborn calves lymphoid nodules in the submucosa with caps of lymphoid tissue in the lamina propria predominated. In three-week-old calves lymphoglandular complexes were as numerous as lymphoid nodules with caps. Scanning and transmission electron microscopical examination of superficial lymphoepithelium over caps and lymphoepithelium in epithelial diverticula of lymphoglandular complexes revealed groups or single cells morphologically resembling M cells, but with widely varying apical processes. To investigate whether these putative M cells in rectal lymphoepithelium internalise and transport macromolecules across the epithelial barrier, ferritin was injected into the rectum of three-week-old calves. Eighty to 150 minutes after exposure ferritin was detected in cells resembling M cells. Thus these cells ought to be considered as M cells. It may be hypothesised that gut-associated lymphoid tissue with specialised lymphoepithelium in the rectum of calves provides a route for the uptake of antigen.
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PMID:M cells in the rectum of calves. 189 24


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