scholarly journals Mast cell binding of neurotensin. II. Molecular conformation of neurotensin involved in the stereospecific binding to mast cell receptor sites.

1977 ◽  
Vol 252 (20) ◽  
pp. 7180-7183
Author(s):  
L H Lazarus ◽  
M H Perrin ◽  
M R Brown ◽  
J E Rivier
Keyword(s):  
Mast Cell ◽  
Molecular Conformation ◽  
Cell Receptor ◽  
Cell Binding ◽  
Receptor Sites

scholarly journals Red cell iron uptake in hereditary microcytic anemia

Blood ◽  
1975 ◽  
Vol 46 (3) ◽  
pp. 381-388 ◽  
Author(s):  
JA Edwards ◽  
JE Hoke
Keyword(s):  
Iron Uptake ◽  
Binding Capacity ◽  
Cell Receptor ◽  
Microcytic Anemia ◽  
Red Cells ◽  
Red Cell ◽  
Cellular Iron ◽  
Receptor Sites ◽  
Cellular Iron Uptake

The iron uptake in vitro of red cells from mice with hereditary microcytic anemia (gene symbol mk) was studied to examine the hypothesis of a generalized impairment of cellular iron uptake in this conidition. Reticulocyte-rich red cells from anemic (mk/mk) and acutely bled normal (+/+) mice were incubated in 59Fe-labeled mouse plasma and the radioiron uptake measured. The 59Fe uptake of the mk/mk and +/+ cells was related in the same way to the reticulocyte concentration, the duration of incubation, and the percentage saturation of the plasma iron-binding capacity. However, under the same conditions, the iron uptake of red cells from normal (+/+) mice was greater than that by red cells from anemic (mk/mk) mice. Furthermore, the cellular loss of radioiron on exposure to EDTA was greater for the mk/mk red cells, although the proportion of the radioiron taken up that was incorporated into heme was the same for mk/mk and +/+ red cells. These results support the hypothesis of a generalized impairment of cellular iron uptake in hereditary microcytic anemia and suggest that there might be a defect in red cell receptor sites for transferrin in this condition.

scholarly journals Mast cell–derived TNF can promote Th17 cell–dependent neutrophil recruitment in ovalbumin-challenged OTII mice

Blood ◽  
2006 ◽  
Vol 109 (9) ◽  
pp. 3640-3648 ◽  
Author(s):  
Susumu Nakae ◽  
Hajime Suto ◽  
Gerald J. Berry ◽  
Stephen J. Galli
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Th17 Cell ◽  
Neutrophil Infiltration ◽  
Cell Receptor ◽  
Neutrophil Recruitment ◽  
T Helper 17 ◽  
Ifn Γ

AbstractBoth mast cells and IL-17 can contribute to host defense and pathology in part by orchestrating neutrophil recruitment, but the possible role of mast cells in IL-17–induced inflammation remains to be defined. We found that mast cells and IL-17, but neither IFN-γ nor FcRγ signaling, contributed significantly to the antigen (Ag)–dependent airway neutrophilia elicited in ovalbumin-specific T-cell receptor (TCR)–expressing C57BL/6-OTII mice, and that IFN-γ significantly suppressed IL-17–dependent airway neutrophilia in this setting. IL-18, IL-1β, and TNF each contributed significantly to the development of Ag- and T helper 17 (Th17 cell)–mediated airway neutrophilia. Moreover, IL-17 enhanced mast cell TNF production in vitro, and mast cell–associated TNF contributed significantly to Ag- and Th17 cell–mediated airway neutrophilia in vivo. By contrast, we detected no significant role for the candidate mediators histamine, PGD2, LTB4, CXCL10, or IL-16, each of which can be produced by mast cells and other cell types, in the neutrophil infiltration elicited in this model. These findings establish that mast cells and mast cell–derived TNF can significantly enhance, by FcRγ-independent mechanisms, the Ag- and Th17 cell–dependent development of a neutrophil-rich inflammatory response at a site of Ag challenge.

An evaluation of antigen B family of Echinococcus granulosus, its conformational propensity and elucidation of the agretope

2009 ◽  
Vol 83 (3) ◽  
pp. 219-224 ◽  
Author(s):  
D. Bhattacharya ◽  
D. Pan ◽  
S. Das ◽  
A.K. Bera ◽  
S. Bandyopadhyay ◽  
...  
Keyword(s):  
Echinococcus Granulosus ◽  
Cell Receptor ◽  
Sensu Stricto ◽  
Predicted Amino Acid Sequence ◽  
Sequence Information ◽  
Mhc Ii ◽  
Antigen B ◽  
Receptor Sites ◽  
Antigenic Index ◽  
Hydrophilic Residues

AbstractThe present communication evaluates the antigen B (AgB) family of bubaline isolates of Echinococcus granulosus with respect to their conformational propensity and also discusses the stretches of agretope. AgB, which is abundantly present in hydatid cyst fluid, is encoded by a gene family, AgB1–AgB5. Hydatidosis is of zoonotic and economic importance in India. Buffaloes serve as the intermediate host. However, to date the AgB family has not been fully analysed. During the present study two different primers used for amplification of AgB1 revealed homology to Echinococcus canadensis (G8) as well as E. granulosus sensu stricto (G1/G2). The sequence of AgB3 is homologous to that of the well-defined species, Echinococcus ortleppi (G5), and the predicted amino acid sequence of AgB4 is homologous to bovine isolates identified earlier. α- and β-amphipathic structures were recorded in all the antigens designated as T-cell receptor sites. The antigenic index of different stretches correlated with hydrophilicity because the hydrophobic residues are not accessible to the cells. In this study, we investigated the binding propensity of AgB to MHC II in order to determine stretches of agretope. Agretopes began with four hydrophilic residues. Two to three additional hydrophilic residues were present in the internal motif. This comparison of AgB and its family of bubaline isolates, with respect to their sequence information, α- and β- amphipathic regions, antigenic index and stretches of agretope is the first such report from India.

scholarly journals Serum factors affecting the incorporation of [3H]uridine by lymphocytes stimulated by concanavalin A. Studies of the role of complement

1973 ◽  
Vol 132 (4) ◽  
pp. 803-812 ◽  
Author(s):  
P. Milthorp ◽  
D. R. Forsdyke
Keyword(s):  
Concanavalin A ◽  
Cell Activation ◽  
Cultured Cells ◽  
Calf Serum ◽  
Cell Receptor ◽  
Serum Factors ◽  
Factors Affecting ◽  
Receptor Sites ◽  
Sequential Binding ◽  
Optimum Response

1. Rat lymph-node cells cultured in serum and medium 199 were activated to transform and proliferate by concanavalin A. Initial cell activation was assessed by measuring the enhanced radioactive labelling of cells with [3H]uridine produced by concanavalin A during the first 6h of culture. 2. In medium containing serum the degree of activation was dependent on the ratio of concanavalin A to non-diffusible serum macromolecules; however, cells could be activated to a normal extent in a medium containing only diffusible molecules. This indicates that certain serum macromolecules buffer cell receptor sites against reaction with concanavalin A. 3. At high concanavalin A concentrations labelling was depressed below that of control cultures without concanavalin A. This inhibition of labelling (i) occurred in calf serum, but not in homologous serum, (ii) was removed by pretreatment of serum with various complement inhibitors, and (iii) first appeared after 1h of culture following an initial phase of cell activation by concanavalin A. Cells pre-labelled with [3H]uridine slowly released the label into the culture medium; this rate of release was suddenly accelerated after 1h of culture with concanavalin A if complement was present. The results suggest that inhibition of labelling requires the sequential binding of concanavalin A and then complement to the cell surface. 4. Results from experiments in which calf serum was mixed in various proportions with calf serum which had been preheated to inactivate complement, suggest (i) a requirement for complement in stoicheiometric quantities dependent on the number of cells being inhibited, and (ii) that preheated serum can inactivate complement in unheated serum. 5. The proliferative response over 3 days of culture was assessed by measuring the enhanced labelling of cells with [3H]thymidine produced by concanavalin A. In preheated calf serum two types of inhibition were noted. (i) A progressive inhibition at high concanavalin A concentrations so that the optimum response was shifted to lower concanavalin A concentrations as the duration of culture was extended; it is suggested that this reflects the secretion of complement by cultured cells. (ii) An inhibition of the optimum response appearing late in the culture period at high cell concentrations; it is suggested that this is due to the exhaustion of medium nutrients in most actively growing cultures.

scholarly journals Congenital hypoplastic anemia inhibition of erythropoiesis by sera from patients with congenital hypoplastic anemia

Blood ◽  
1975 ◽  
Vol 45 (1) ◽  
pp. 83-89 ◽  
Author(s):  
JA Ortega ◽  
NA Shore ◽  
PP Dukes ◽  
D Hammond
Keyword(s):  
Stem Cell ◽  
Cell Receptor ◽  
Normal Serum ◽  
Heme Synthesis ◽  
Receptor Sites ◽  
Hypoplastic Anemia ◽  
Marrow Cells

An in vitro marrow culture assay designed to measure erythropoietic capability was used to ascertain the presence of an inhibitor in the sera of patients with congenital hypoplastic anemia (CHA). Marrow cells from nine anemic CHA patients responded to the stimulatory effect of exogenous erythropoietin (EPO) by an increase in heme synthesis in the presence of normal serum. The effect on heme synthesis was less than that observed with normal marrow cells. CHA serum inhibited heme synthesis by both normal and CHA marrow cells. It is concluded that an in-inhibitor of erythropoiesis is present in serum from CHA patients. This inhibitor most likely blocks the EPO-sensitive stem cell receptor sites, causing decreased response to the hormone.

scholarly journals Rabaptin-5 regulates receptor expression and functional activation in mast cells

Blood ◽  
2008 ◽  
Vol 112 (10) ◽  
pp. 4148-4157 ◽  
Author(s):  
Eon J. Rios ◽  
Adrian M. Piliponsky ◽  
Chisei Ra ◽  
Janet Kalesnikoff ◽  
Stephen J. Galli
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Receptor ◽  
Small Gtpase ◽  
Receptor Expression ◽  
Interacting Protein ◽  
Surface Stability ◽  
Cell Adhesion And Migration ◽  
And Migration ◽  
High Affinity Ige Receptor

Abstract Rab5 is a small GTPase that regulates early endocytic events and is activated by RabGEF1/Rabex-5. Rabaptin-5, a Rab5 interacting protein, was identified as a protein critical for potentiating RabGEF1/Rabex-5's activation of Rab5. Using Rabaptin-5 shRNA knockdown, we show that Rabaptin-5 is dispensable for Rab5-dependent processes in intact mast cells, including high affinity IgE receptor (FcϵRI) internalization and endosome fusion. However, Rabaptin-5 deficiency markedly diminished expression of FcϵRI and β1 integrin on the mast cell surface by diminishing receptor surface stability. This in turn reduced the ability of mast cells to bind IgE and significantly diminished both mast cell sensitivity to antigen (Ag)-induced mediator release and Ag-induced mast cell adhesion and migration. These findings show that, although dispensable for canonical Rab5 processes in mast cells, Rabaptin-5 importantly contributes to mast cell IgE-dependent immunologic function by enhancing mast cell receptor surface stability.

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