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Biomedical subjects

W Born

Publications and source records attributed to W Born.

At least 37 records · Page 2Linked to original sources
PubMed1993

Stimulation of calcitonin/CGRP-I and CGRP-II gene expression by dibutyryl cAMP in a human medullary thyroid carcinoma (TT) cell line.

In a human medullary thyroid carcinoma (TT) cell line, expression of the calcitonin (CT)/CT gene-related peptide (CGRP-I) gene (CALC-I or alpha) at the level of mRNA and of encoded peptides is higher than that of the closely related CGRP-II gene (CALC-II or beta). In response to 1 mM dibutyryl cAMP ((Bu)2cAMP), mature CGRP-II mRNA and intact cellular CGRP-II were raised 65- and 10-fold, respectively, at 72 h. Also at 72 h, 1 mM sodium butyrate enhanced CGRP-II mRNA only 9-fold and cellular CGRP-II 2-fold; stimulation of CGRP-I and CT mRNA and of cellular CGRP-I and CT by both (Bu)2cAMP and sodium butyrate was similarly low. During the same incubation time period secreted CGRP-II was raised 44-fold in response to (Bu)2cAMP, and CGRP-I and CT 8- and 42-fold, respectively. In conclusion, gene products of CALC-I (CGRP-I and CT) are present in higher amounts in TT cells than those of CALC-II (CGRP II). Yet (Bu)2cAMP predominantly stimulates the expression of CALC-II.

Bucladesine↗
PubMed1992

Comparison of a calcitonin gene-related peptide receptor in a human neuroblastoma cell line (SK-N-MC) and a calcitonin receptor in a human breast carcinoma cell line (T47D).

A specific CGRP-binding protein of M(r) 60,000 has been identified in the human neuroblastoma cell line SK-N-MC. After N-deglycosylation a M(r) of 48,000 was found. The M(r) were indistinguishable from those determined in the human cerebellum. Receptor binding of CGRP is coupled to cyclic AMP formation. The latter is antagonized by hCGRP-I8-37. CT and DAPamide interact only minimally with the CGRP receptor, whereas CGRP and DAPamide are full agonists in T47D cells. The CT receptor on human breast cancer cell line T47D is clearly different from the human CGRP receptor.

Amino Acid Sequence↗
PubMed1992

Heat shock protein Hsp60-reactive gamma delta cells: a large, diversified T-lymphocyte subset with highly focused specificity.

Previously, we detected a subset of gamma delta T cells in the newborn mouse thymus that responded to the mycobacterial heat shock protein Hsp60, as well as with what seemed to be a self-antigen. All of these cells expressed V gamma 1, most often in association with V delta 6+. It was not clear, however, whether similar, mature gamma delta cells with Hsp60 reactivity are common outside of the thymus, or rather, whether they are largely eliminated during development. From the data presented here, we estimate that gamma delta cells responding to Hsp60 comprise 10-20% of normal splenic and lymph node gamma delta T cells. Such cells, derived from adult spleen, always express a V gamma 1-J gamma 4-C gamma 4 gamma chain, although not all cells with this gamma chain show Hsp60 reactivity. Many of these V gamma 1+ cells also express V delta 6-J delta 1-C delta, though fewer than in V gamma 1+ cells from the newborn thymus. Extensive diversity is evident in both the gamma and delta chain junctional amino acids of the receptors of these cells, indicating that they may largely develop in the thymus of older animals or undergo peripheral expansion. Finally, we found that all such cells responding to both a putative self-antigen and to mycobacterial Hsp60 respond to a 17-amino acid synthetic peptide representing amino acids 180-196 of the Mycobacterium leprae Hsp60 sequence. This report demonstrates that a large subset of Hsp60-reactive peripheral lymphoid gamma delta T cells preexists in normal adult mice, all members of which respond to a single segment of this common heat shock protein.

Animals↗
PubMed1992

Intracolonic bioavailability of human calcitonin in man.

Human calcitonin (hCT) injected into the lumen of the descending colon of normal human subjects was absorbed within minutes and could be recognized intact in plasma as shown by RIA in combination with reverse-phase HPLC. The absorption was low and variable, with bioavailabilities ranging from 0.01% to 2.7% relative to intravenously administered hCT (area under the concentration-time curve). With intravenous hCT serum calcium was lowered and the fractional urinary excretion of calcium, phosphorus, sodium and chloride was significantly stimulated. With the intracolonic hCT, the fractional urinary excretions of calcium, sodium and chloride were also marginally stimulated relative to intracolonic vehicle (placebo). In conclusion, hCT is absorbed intact from the colon, but the bioavailability is low and highly variable.

Adult↗
PubMed1991

Characterization and photoaffinity labeling of a calcitonin gene-related peptide receptor solubilized from human cerebellum.

Calcitonin gene-related peptide (CGRP) receptors were solubilized from human (h) cerebellum with use of the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS). Scatchard analysis of equilibrium binding data indicated that the soluble extract contained a single class of CGRP binding sites with apparent dissociation constants of 50 pM for the intact 125I-hCGRP-I(1-37) and 160 pM for the antagonist 125I-hCGRP-I(8-37). Unlabeled hCGRP-I and -II and hCGRP-I(8-37) displaced 125I-hCGRP-I from solubilized CGRP receptors with similar potencies (ID50 = 70-150 pM). Human CGRP-I(15-37), -(21-37), and -(28-37) were less potent (ID50 greater than or equal to 70 nM), suggesting that amino acid residues 8-14 may be important for maintaining high binding affinity. A novel photoreactive analogue of hCGRP-I, 125I-[C gamma-(4-azidoanilino)Asp3] hCGRP-I, was prepared by carbodiimide coupling of 4-azidoaniline to 125I-hCGRP-I. Photoaffinity labeling of soluble CGRP receptors with the photoreactive analogue and analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography revealed three specifically labeled binding proteins with apparent molecular weights (Mr) of 60,000, 54,000, and 17,000. Cross-linking of 125I-hCGRP-I and -II and 125I-hCGRP-I(8-37) to soluble CGRP binding sites using disuccinimidyl suberate revealed three specifically labeled binding proteins with the same Mr. The C-terminal fragment 125I-hCGRP-I(8-37), unlike the intact peptide, was, furthermore, cross-linked specifically to a 95,000 Mr protein. The CGRP receptor is N-glycosylated. Treatment with endoglycosidase F/N-glycosidase F converted the 60,000 and 54,000 to 46,000 and 41,000 Mr components.(ABSTRACT TRUNCATED AT 250 WORDS)

Affinity Labels↗
PubMed1991

Diagnostic relevance of the amino-terminal cleavage peptide of procalcitonin (PAS-57), calcitonin and calcitonin gene-related peptide in medullary thyroid carcinoma patients.

We have identified the amino-terminal cleavage peptide of procalcitonin (PAS-57) in the plasma of normal human subjects and of medullary thyroid carcinoma (MTC) patients together with calcitonin (CT) and CT gene-related peptide (CGRP). Major components on reversed-phase high-pressure liquid chromatography had the retention times of synthetic PAS-57, CT and CGRP as well as of precursor proteins. Plasma levels of PAS-57 (290 +/- 50 pgeq/ml; mean +/- S.E.M.), CT (27 +/- 8 pgeq/ml) and CGRP (8.4 +/- 0.8 pgeq/ml) were respectively 2.3-, 1.6- and 1.5-fold higher in normal men (n = 10) than in women (n = 8). In response to 1 min intravenous calcium infusions (2 mg per kilogram body weight) PAS-57 and CT were increased 3.5- and 2.7-fold (P less than 0.001), respectively, but CGRP remained unchanged. In MTC patients (n = 57) with raised levels of PAS-57 and CT, the molar ratio between PAS-57 and CT was 1.7-times higher than in normal subjects (P less than 0.01). We have found that PAS-57 is a predominant CT/CGRP gene derived product in the circulation of normal subjects and of MTC patients and a potential new MTC tumor marker.

Adult↗
PubMed1991

Alpha beta T-lymphocyte depleted mice, a model for gamma delta T-lymphocyte functional studies.

Adult mice can be depleted of essentially all mature alpha beta T lymphocytes by chronic treatment with the framework-recognizing, pan-specific anti-TCR alpha beta mAb, H57-597. Similar findings have been reported in rats, gamma delta cell populations remain essentially unaltered in size and reactivity. Suppression of alpha beta T-cell development results in the loss of alloantigen reactivity and of B-cell help, suggesting that gamma delta and alpha beta populations differ in their functional capabilities. Indirect effects of the antibody treatment include quantitative changes in splenic B cells, as well as reduced sizes and weights of experimental animals. alpha beta-suppressed mice and rats may provide model systems for studies on gamma delta cell function in vivo.

Animals↗
PubMed1991

Recognition of a single hsp-60 epitope by an entire subset of gamma delta T lymphocytes.

We can conclude that a large subset of gamma delta cells, present in both murine newborn thymus and in adult spleen, respond to the stress protein, hsp60. hsp60 seems to be stimulatory whether it is derived from a foreign pathogen such as mycobacteria, or whether it originates from the mouse's own cells. The gamma delta cells that respond to this antigen bear very similar receptors, all expressing V gamma 1 and most expressing V delta 6, although their junctional variations indicate that not all members of the subset stem from clonal expansion of only one or a few cells. The hsp60-reactive subset has not at this time been shown to "home" to an epithelial location, in contrast to other known gamma delta cell subsets, and may rather carry out its functions while in circulation. Whether the hsp60 antigen requires a "presenting" molecule remains at this point unclear, but because the gamma delta cells all respond to a synthetic peptide representing an epitope of hsp60, presentation is implied. Human gamma delta cells that respond to PPD from mycobacteria, as do the mouse hsp60-reactive gamma delta cells, have also been described, many as members of a major subset in peripheral blood, although only rarely have these been reported to respond to mycobacterial hsp60. The antigenic source in PPD for these cells has not yet been determined, but as for the mouse, a low molecular weight peptide appears to be sufficient for stimulation (P. Brennan and R. Modlin, personal communication). The PPD-reactive gamma delta cells, when their receptors have been characterized, have been found to express a V gamma 9+ chain. Some evidence indicates that these cells can also recognize self hsp60; hence, in several ways, this human subset has characteristics similar to the mouse hsp60-reactive subset. Perhaps gamma delta cells that respond to hsp60 play an important role, in both mice and humans, in the detection of transformed self cells or cells containing intracellular pathogens, that escape detection by alpha beta T cells.

Amino Acid Sequence↗
PubMed1991

Possible links between immune system and stress response: the role of gamma delta T lymphocytes.

Heterologous heat shock proteins (hsps) are antigens in many infectious diseases involving bacteria, parasites and perhaps even fungi. T and B lymphocytes recognize multiple epitopes on these proteins. Recently, lymphocytes expressing gamma delta T cell receptors (gamma delta cells) were also found to react with hsps that are members of the 60 kiloDalton (kDa) family. The response of gamma delta cells to hsp 60 differs from that of alpha beta T cells and B cells in several ways: the frequency of reactive gamma delta clones is high. Many clones recognize the same portion of this protein instead of scattered antigenic epitopes; and most gamma delta cells that react with the mycobacterial hsp-60 homolog are also stimulated by the autologous homolog. Perhaps, such (self) hsp-reactive gamma delta populations function by distinguishing stressed from not stressed states in autologous cells and tissues, rather than by discriminating 'self' and 'non-self'.

Bacterial Proteins↗
PubMed1991

Heat shock proteins as antigens for gamma delta T cells.

Recently, there have been a number of reports that gamma delta T cells are stimulated by heat shock, or stress, proteins. Although some alpha beta T cells are capable of recognizing heat shock proteins, we speculate that most or a group of gamma delta cells generally recognize this type of antigen. Recognition of heat shock proteins would enable gamma delta cells to respond to autologous tissue, and perhaps thus eliminate those cells that exhibit signs of stress, due for example to intracellular infection or transformation.

Animals↗
PubMed1990

Expression of gamma/delta T cell receptors on lymphocytes from the lactating mammary gland.

gamma/delta cells were at least four times more frequent in lactating mouse mammary glands than among T cells of the most proximal lymph nodes. Two-color staining of freshly isolated T cells and a study of clonally expressed gamma/delta receptors on hybridomas further revealed that the mammary gamma/delta population is heterogeneous, including at least three different subsets, among them cells expressing V gamma 5, V gamma 4 together with V delta 4, or none of these V regions.

Animals↗
PubMed1990

Isolation from adult human serum of four insulin-like growth factor (IGF) binding proteins and molecular cloning of one of them that is increased by IGF I administration and in extrapancreatic tumor hypoglycemia.

We have isolated four insulin-like growth factor binding proteins (IGFBPs) from adult human serum by insulin-like growth factor (IGF) I affinity chromatography and high performance liquid chromatography. A 36-kDa binding protein (BP), not digestible with N-glycanase, is increased in patients with extrapancreatic tumor hypoglycemia and during IGF I administration in healthy adults. Its 38 NH2-terminal amino acids are identical to those of an IGFBP sequence derived from a human cDNA that cross-hybridizes with the rat IGFBP-2 cDNA. With probes encoding a NH2-terminal, COOH-terminal, and a middle region of this protein we have obtained three cDNA clones from a Hep G2 cDNA library; one encodes human IGFBP-2, and the other two presumably represent unspliced heteronuclear and alternatively spliced mRNA, respectively. A 28-30-kDa IGFBP represents a novel BP species in human serum. Its 30 NH2-terminal amino acids are not homologous to IGFBP-1, -2, or -3. It is not digestible with N-glycanase and does not bind 125I-IGF I. The NH2-terminal sequences of a 42/45- and a 31-kDa IGFBP are identical to that of human IGFBP-3. The 42/45-kDa proteins are two glycosylation variants of BP-3. The 31-kDa protein presumably is a degradation product of BP-3 that lacks the COOH terminus. It is likely that the different IGFBPs modulate auto-/paracrine and endocrine effects of IGFs on growth and metabolism in a different and specific manner.

Adult↗
PubMed1990

Recognition of a peptide antigen by heat shock--reactive gamma delta T lymphocytes.

Small synthetic peptides that correspond to different portions of the 65-kilodalton mycobacterial heat shock protein (Hsp65) were used to identify a putative antigenic epitope for gamma delta cells. Weaker gamma delta responses to the equivalent portion of the autologous homolog, mouse Hsp63, were also seen. The stimulatory epitope overlaps with an epitope recognized by arthritogenic alpha beta T cell clones. The data suggest that gamma delta cells have a role in autoimmune disorders and imply that these cells recognize ligands by a mechanism similar to that of alpha beta T lymphocytes, that is, in the form of small processed protein fragments bound to antigen-presenting molecules.

Amino Acid Sequence↗
PubMed1990

Recognition of heat shock proteins and gamma delta cell function.

Recently evidence has accumulated suggesting that gamma delta cells may participate in the immune response to mycobacteria and other infectious organisms. Many mouse gamma delta cells are stimulated by the 65 kDa heat shock protein of M. bovis and human gamma delta cell lines reactive with this mycobacterial protein have also been isolated. Indirect evidence further suggests that gamma delta cells can recognize autologous heat shock proteins. In this article, Willi Born and colleagues focus on these and other recent findings and speculate on their importance to gamma delta cell function in vivo.

Animals↗