scholarly journals Increase in somatostatin to glucagon ratio in islets of alloxan-diabetic dogs: effect of insulin-induced euglycemia

1993 ◽  
Vol 71 (7) ◽  
pp. 512-517 ◽  
Author(s):  
K. S. Rastogi ◽  
P. L. Brubaker ◽  
A. Kawasaki ◽  
S. Efendic ◽  
M. Vranic
Keyword(s):  
B Cell ◽  
Insulin Content ◽  
Cell Area ◽  
Pancreatic Glucagon ◽  
Marked Inhibition ◽  
A Cell ◽  
D Cell ◽  
Diabetic Dogs

We have previously shown that acute insulin-induced normalization of glycemia in alloxan-diabetic (A-D) dogs results in marked inhibition of total pancreatic glucagon content, but normalization of somatostatin content. We suggested that this glucagon deficiency might account for A-cell unresponsiveness in diabetes. To examine these changes in detail at the islet level, morphometric and immunologic analyses were carried out on pancreata from four normal (N), four hyperglycemic A-D dogs (HD), and four A-D dogs after acute normalization of glycemia with insulin (ND). The total number of islets per pancreas (3.9 × 106 ± 0.5 × 106; determined from the number of islets per square millimetre) was reduced by 60% (p < 0.001) in HD, and this was not affected by acute normalization of glycemia. Insulin content per islet was 1247 ± 205 pg in N, and this was reduced in both HD and ND to 2 and 5%, respectively (p < 0.001). Similarly, insulin-containing B-cell area was 76 ± 1% of the total islet area in N, and was unmeasurable in HD and ND. Glucagon content per islet was 89 ± 6 pg in N, and this was increased by 215% (p < 0.001) in HD, but was normalized in ND. The A-cell area increased concomitantly by 170% from 17 ±1 to 46 ± 2% (p < 0.01) of islet area in HD, and remained elevated in ND. In contrast, somatostatin content per islet was 3.0 ± 1.1 pg in N, but was increased by 567% (p < 0.01) in HD and fell to 200% (p = ns) of N in ND. D-cell area increased by 55% in HD, from 11.5 ± 0.8 to 17.8 ± 0.9% (p < 0.01), and remained elevated at 15.6 ± 1.1% (p < 0.01) in ND. The ratio of somatostatin to glucagon content in the islet was therefore 0.03 ± 0.01 in N, and this was increased by 167 (p = ns) and 333% (p < 0.05) in HD and ND, respectively. We speculate that the increase in the islet somatostatin to glucagon ratio in normoglycemic diabetic dogs may play a role in the suppression of glucagon responses in diabetes.Key words: islet, glucagon, somatostatin, diabetes, insulin-induced euglycemia.

Transient antibiotic-induced changes in the neonatal swine intestinal microbiota impact islet expression profiles reducing subsequent function

2021 ◽  
Author(s):  
Carla Sosa Alvarado ◽  
Kaiyuan Yang ◽  
Hongbo Qiu ◽  
Erinn Mills ◽  
Janelle M Fouhse ◽  
...  
Keyword(s):  
B Cell ◽  
Pancreatic Islets ◽  
Expression Profiles ◽  
Human Infant ◽  
Metabolic Phenotype ◽  
Insulin Content ◽  
Cell Area ◽  
Human Infants ◽  
16S Sequencing ◽  
Neonatal Piglets

Neonatal antibiotics administered to human infants initiate gut microbiota dysbiosis that may have long-term effects on body weight (BW) and metabolism. We examined antibiotic-induced adaptations in pancreatic islets of the piglet, a well-accepted model of human infant microbiota and pancreas development. Neonatal piglets randomized to amoxicillin (30mg/kg BW/day; n=7, ANTI) or placebo (vehicle control; n=7, CON) from postnatal day (PND)0-13 were euthanized at PND7, 14 and 49. The metabolic phenotype along with functional, immunohistological and transcriptional phenotypes of the pancreatic islets were studied. The gut microbiome was characterized by 16S sequencing and microbial metabolites and microbiome-sensitive host molecules were measured. Compared with CON, ANTI PND7 piglets had elevated transcripts of genes involved in GLP-1 synthesis or signaling in islets (p<0.05) coinciding with higher plasma GLP-1 (p=0.11), along with increased Tnf (p<0.05) and Npg1 (p<0.05). Antibiotic-induced relative increases in Escherichia, Coprococcus, Ruminoccocus, Dehalobacterium and Oscillospira of the ileal microbiome at PND7 normalized after antibiotic withdrawal. In ANTI islets at PND14, the expression of key regulators Pdx1, Igf2 and Tcf7l2 was down-regulated, preceding a 40% reduction of b-cell area (p<0.01) and islet insulin content at PND49 (p<0.05). At PND49, a 2-fold elevated plasma insulin concentration (p=0.07) was observed in ANTI compared with CON. We conclude that antibiotic treatment of neonatal piglets elicits gut microbial changes accompanied by phasic alterations in key regulatory genes in pancreatic islets at PND7 and 14. By PND49, reduced b-cell area and islet insulin content were accompanied by elevated non-fasted insulin despite normoglycemia, indicative of islet stress.

scholarly journals Selection of a Nuclease-Resistant RNA Aptamer Targeting CD19

Cancers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 5220
Author(s):  
Carla L. Esposito ◽  
Katrien Van Roosbroeck ◽  
Gianluca Santamaria ◽  
Deborah Rotoli ◽  
Annamaria Sandomenico ◽  
...  
Keyword(s):  
B Cell ◽  
Binding Activity ◽  
Rna Aptamer ◽  
Transmembrane Glycoprotein ◽  
B Cell Malignancy ◽  
A Cell ◽  
Enrichment Protocol ◽  
Interesting Class ◽  
Exponential Enrichment ◽  
Cluster Of Differentiation

The transmembrane glycoprotein cluster of differentiation 19 (CD19) is a B cell–specific surface marker, expressed on the majority of neoplastic B cells, and has recently emerged as a very attractive biomarker and therapeutic target for B-cell malignancies. The development of safe and effective ligands for CD19 has become an important need for the development of targeted conventional and immunotherapies. In this regard, aptamers represent a very interesting class of molecules. Additionally referred to as ‘chemical antibodies’, they show many advantages as therapeutics, including low toxicity and immunogenicity. Here, we isolated a nuclease-resistant RNA aptamer binding to the human CD19 glycoprotein. In order to develop an aptamer also useful as a carrier for secondary reagents, we adopted a cell-based SELEX (Systematic Evolution of Ligands by EXponential Enrichment) protocol adapted to isolate aptamers able to internalise upon binding to their cell surface target. We describe a 2′-fluoro pyrimidine modified aptamer, named B85.T2, which specifically binds to CD19 and shows an exquisite stability in human serum. The aptamer showed an estimated dissociation constant (KD) of 49.9 ± 13 nM on purified human recombinant CD19 (rhCD19) glycoprotein, a good binding activity on human B-cell chronic lymphocytic leukaemia cells expressing CD19, and also an effective and rapid cell internalisation, thus representing a promising molecule for CD19 targeting, as well as for the development of new B-cell malignancy-targeted therapies.

Insulin release from a cloned precursor beta cell line

1987 ◽  
Vol 113 (1) ◽  
pp. 3-NP ◽  
Author(s):  
K. W. Ng ◽  
P. R. Gummer ◽  
B. L. Grills ◽  
V. P. Michelangeli ◽  
M. E. Dunlop
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Line ◽  
Insulin Release ◽  
Cell Lines ◽  
Neonatal Rat ◽  
Insulin Content ◽  
Morphological Evidence ◽  
Bicarbonate Buffer ◽  
Beta Cell Line

ABSTRACT This paper describes the establishment in long-term tissue culture of a functional, clonal beta (B) cell line UMR 407/3 derived from neonatal rat pancreas. Immunofluorescence demonstrated specific and uniform staining for insulin. Transmission electron microscopy showed the presence of microvilli and cytoplasmic granules. The doubling time in culture was approximately 60 h in 2% (v/v) fetal calf serum with inhibition of growth at confluence. Biochemical studies demonstrated the incorporation of [3H]leucine into proinsulin and insulin, with insulin comprising 43·6% of the total radioactivity incorporated into immune complexes. When incubated at 37 °C for 30 min with Krebs–Ringer bicarbonate buffer (pH 7·4), the amount of insulin released on stimulation by 16·7 mmol glucose/l, 20 mmol dl-glyceraldehyde/l or 20 mmol α-ketoisocaproate/l was significantly higher compared with 5·6 mmol glucose/l. The mean insulin content was equivalent to 99±0·4 fmol (s.e.m.)/5 × 105 cells. Regulated insulin release was maintained through at least 15 passages in culture. The cells showed morphological evidence of senescence after passage 26 and this was associated with significant reduction in stimulated insulin release as well as insulin content. The ability of the cells of this clonal line to grow in soft agar suggests that it is a precursor cell line. The clonal B cell lines isolated so far may thus represent variably committed rather than fully differentiated B cells in culture. These clonal non-neoplastic cell lines will be useful models with which to study the regulation of maturation/differentiation of B cells and insulin gene expression. Finally, the method described for the isolation of clonal B cell lines can be used to establish, in culture, precursor clonal lines from other normal tissues. J. Endocr. (1987) 113, 3–10

A cell type-specific transcriptomic approach to map B cell and monocyte type I interferon-linked pathogenic signatures in Multiple Sclerosis

2019 ◽  
Vol 101 ◽  
pp. 1-16 ◽  
Author(s):  
Martina Severa ◽  
Fabiana Rizzo ◽  
Sundararajan Srinivasan ◽  
Marco Di Dario ◽  
Elena Giacomini ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
B Cell ◽  
Type I Interferon ◽  
Type I ◽  
Cell Type ◽  
A Cell ◽  
Cell Type Specific

scholarly journals Inhibition of antibody-dependent cellular cytotoxicity and immunoglobulin synthesis by an antiserum prepared against a human B-cell Ia-like molecule.

1976 ◽  
Vol 144 (1) ◽  
pp. 113-122 ◽  
Author(s):  
L Chess ◽  
R Evans ◽  
R E Humphreys ◽  
J L Strominger ◽  
S F Schlossman
Keyword(s):  
Cell Surface ◽  
B Cell ◽  
Specific Antigen ◽  
Cell Populations ◽  
Antibody Dependent Cellular Cytotoxicity ◽  
Physical Separation ◽  
Effector Cells ◽  
Antigen Complex ◽  
A Cell ◽  
Human B Cell

Rabbit antisera to the human B-cell-specific antigen complex, p23,30, was used to define further the functional heterogeneity of isolated human lymphocyte subpopulations. Specific depletion of p23,30-bearing cells from Ig-negative cell populations and Ig-negative, E rosette-negative (Null) populations by either complement-mediated lysis or by physical separation on goat antirabbit Fab immunoabsorbent columns, eliminates the antibody-dependent cellular cytotoxic (ADCC) function. Furthermore, binding of anti-p23,30 serum to the effector cell surface inhibits ADCC but does not interfere with EA rosette formation. Apparently p23,30 represents a cell surface site which is distinct from the Fc receptor but which is important in the triggering of ADCC. In addition, depletion of p23,30-bearing cells from unfractionated cell populations, Ig-positive B-cell populations and Ig-negative, E rosette-negative (Null) populations eliminates the capacity of these populations to secrete immunoglobulin during subsequent culturing. Thus both the Ig-secreting cells and the ADCC effector cells within the Ig-negative, E rosette-negative (Null) population reside in the same population of cells which bears the p23,30 antigen.

scholarly journals Endotoxin protein: a B-cell mitogen and polyclonal activator of C3H/HeJ lymphocytes.

1976 ◽  
Vol 144 (3) ◽  
pp. 821-827 ◽  
Author(s):  
B M Sultzer ◽  
G W Goodman
Keyword(s):  
B Cell ◽  
Lipid A ◽  
Protein A ◽  
Cell Wall Protein ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Lipopolysaccharide Endotoxin ◽  
Polyclonal Activator ◽  
A Cell ◽  
Cell Mitogen

A cell wall protein that is ordinarily complexed to the lipopolysaccharide endotoxin in gram-negative bacteria has been separated by the use of aqueous phenol. The protein is active as a B-cell mitogen and polyclonal activator of murine lymphocytes including the C3H/HeJ strain which is a nonresponder to lipoplysaccharide or lipid A.

scholarly journals BINDING OF SOLUBLE IMMUNE COMPLEXES TO HUMAN LYMPHOBLASTOID CELLS

1974 ◽  
Vol 140 (4) ◽  
pp. 877-894 ◽  
Author(s):  
Argyrios N. Theofilopoulos ◽  
Frank J. Dixon ◽  
Viktor A. Bokisch
Keyword(s):  
Cell Surface ◽  
B Cell ◽  
Cell Lines ◽  
Immune Complexes ◽  
Surface Membrane ◽  
Raji Cells ◽  
Human Lymphoblastoid Cell ◽  
C Cell ◽  
A Cell ◽  
Soluble Immune Complexes

In the present work we studied the expression of membrane-bound Ig (MBIg) as well as receptors for IgG Fc and complement on nine human lymphoblastoid cell lines. When MBIg and receptors for IgG Fc were compared, four categories of cell lines could be distinguished: (a) cell lines having both MBIg and receptors for IgG Fc, (b) cell lines having MBIg but lacking receptors for IgG Fc, (c) cell lines lacking MBIg but having receptors for IgG Fc, and (d) cell lines lacking both MBIg and receptors for IgG Fc. Two types of receptors for complement could be detected on the cell lines studied, one for C3-C3b and one for C3d. When sensitized red cells carrying C3b or C3d were used for rosette tests, three categories of cell lines could be distinguished: (a) cell lines having receptors for C3b and C3d, (b) cell lines having receptors only for C3d and (c) cell lines lacking both receptors. However, when a more sensitive immunofluorescent method was used instead of the rosette technique, it was found that cell lines unable to form rosettes with EAC1423bhu were able to bind soluble C3 or C3b which indicated the presence of these receptors on the cell surface. Inhibition experiments showed that receptors for C3-C3b and receptors for C3d are distinct and that receptors for C3-C3b and C3d are different from receptors for IgG Fc. A cell line (Raji) without MBIg but with receptors for IgG Fc, C3-C3b, and C3d was selected for use in studying the binding mechanism of soluble immune complexes to cell surface membrane. Aggregated human gamma globulin was used in place of immune complexes. Immune complexes containing complement bind to Raji cells only via receptors for complement, namely receptors for C3-C3b and C3d. Binding of immune complexes containing complement to cells is much greater than that of complexes without complement. Immune complexes bound to cells via receptors for complement can be partially released from the cell surface by addition of normal human serum as well as isolated human C3 or C3b. We postulate that such release is due to competition of immune complex bound C3b and free C3 or C3b for the receptors on Raji cells.

Establishment of a cell line from a chemotherapy resistant diffuse large B-cell lymphoma

2007 ◽  
Vol 48 (5) ◽  
pp. 1038-1041 ◽  
Author(s):  
Mattias Berglund ◽  
Ulf Thunberg ◽  
Marie Fridberg ◽  
Anette Gjörloff Wingren ◽  
Joachim Gullbo ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Line ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Large B Cell Lymphoma ◽  
A Cell ◽  
Large B Cell

Enhanced B Cell Activation in the Absence of CD81

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2578-2578
Author(s):  
Mrinmoy Sanyal ◽  
Rosemary Fernandez ◽  
Shoshana Levy
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Activation ◽  
Cell Receptor ◽  
Free Calcium ◽  
B Cell Activation ◽  
Membrane Reorganization ◽  
A Cell

Abstract CD81 is a component of the CD19/CD21 coreceptor complex in B cells. This tetraspanin molecule was previously shown to enable membrane reorganization in B cells responding to complement-bound antigens. Here we stimulated B cells via their B cell receptor (BCR) and demonstrate that Cd81−/− B cells fluxed higher intracellular free calcium ion along with increased phosphorylation of PLCγ2 and Syk. The stimulated Cd81−/− B cells also proliferated faster and secreted higher amounts of antibodies. Moreover, activation of the TLR4 pathway in Cd81−/− B cells induced increased proliferation and antibody secretion. Furthermore, Cd81−/− mice mounted a significantly higher immune response to T-cell independent antigens than their wildtype counterparts. Finally, analysis of Cd81−/− B cells that were generated by bone marrow transplantation into Rag1−/− mice confirmed a cell intrinsic hyperactive phenotype. Taken together, these results indicate that CD81 plays a negative role in B cell activation in vitro and in vivo.

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