scholarly journals A monoclonal antibody that blocks adhesion of Chlamydomonas mt+ gametes.

1986 ◽  
Vol 103 (6) ◽  
pp. 2449-2456 ◽  
Author(s):  
W J Snell ◽  
M G Kosfiszer ◽  
A Clausell ◽  
N Perillo ◽  
S Imam ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Chlamydomonas Reinhardtii ◽  
Adhesion Molecules ◽  
Cyanogen Bromide ◽  
Surface Molecule ◽  
Surface Adhesion ◽  
Vegetative Cells ◽  
Mating Reaction

During the mating reaction (fertilization) in the biflagellated alga, Chlamydomonas reinhardtii, mt+ and mt- gametes adhere to each other via their flagella and subsequently fuse to form quadriflagellated zygotes. In the studies reported here, we describe a monoclonal antibody directed against an mt+ flagellar surface molecule. The antibody blocks the adhesiveness of mt+ gametes, isolated mt+ flagella, and detergent extracts thereof. It has no effect on mt- gametes. Cyanogen bromide-activated Sepharose beads derivatized with the antibody bind only mt+ gametes; mt- gametes and mt+ and mt- vegetative cells are unreactive with the derivatized beads. The interaction of mt+ gametes with the beads is dynamic and cells continuously bind, detach, and rebind to the beads. Surprisingly, antibody-derivatized beads that have been incubated with mt+ gametes acquire the ability to bind mt- gametes. Moreover, extraction of the preincubated beads with detergents releases active mt+ adhesion molecules. The evidence suggests that binding of the antibody to the flagellar surface adhesion molecules causes their release from the flagellar surface, possibly mimicking the normal mechanism of flagellar de-adhesion.

scholarly journals Size heterogeneity, phosphorylation and transmembrane organisation of desmosomal glycoproteins 2 and 3 (desmocollins) in MDCK cells

1990 ◽  
Vol 96 (2) ◽  
pp. 239-248
Author(s):  
E.P. Parrish ◽  
J.E. Marston ◽  
D.L. Mattey ◽  
H.R. Measures ◽  
R. Venning ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Cell Adhesion ◽  
Adhesion Molecules ◽  
Cell Adhesion Molecules ◽  
Mdck Cells ◽  
Intact Cells ◽  
Specific Antibodies ◽  
Metabolic Labelling ◽  
Membrane Spanning ◽  
Size Heterogeneity

Metabolic labelling with [35S]methionine and immunoprecipitation with specific antibodies to bovine desmosomal glycoproteins 2 and 3 (dg2 and dg3: desmocollins) reveals a triplet of polypeptides of Mr 115,000, 107,000 and 104,000 in MDCK cells. Tunicamycin treatment shows that this heterogeneity does not arise through differential N-linked glycosylation. Under conditions in which cells are actively forming desmosomes, the largest polypeptide, dg2, becomes phosphorylated on serine, but the two smaller polypeptides, dg3a and 3b, do not. Controlled trypsinisation of intact cells yields three membrane-protected fragments (Mr 28,000, 24,000 and 23,000) derived from these glycoproteins. The largest of these fragments is phosphorylated but the two smaller fragments are not. A monoclonal antibody to bovine dg2 and dg3 stains MDCK cells cytoplasmically. In immunoblotting of MDCK cells the monoclonal antibody recognises dg2 strongly and shows a weaker reaction with a band of lower Mr corresponding to dg3a. It also recognises the immunoprecipitated 28,000 Mr fragment from trypsinised cells and a smaller fragment of 24,000 Mr. The simplest interpretation of these data is that all three glycoproteins have a transmembrane configuration with a single membrane-spanning domain, and show heterogeneity of size and phosphorylation in their cytoplasmic domains. The data are discussed in relation to the known structures of some cell adhesion molecules. Questions about the relative roles and distributions of the different polypeptides in desmosomal organisation are raised.

Plasma and endothelial cell-surface adhesion molecules and cardiopulmonary bypass

2000 ◽  
Vol 9 (3) ◽  
pp. A185
Author(s):  
Michael P. Vallely ◽  
Paul G. Bannon ◽  
Clifford F. Hughes ◽  
Leonard Kritharides
Keyword(s):  
Cardiopulmonary Bypass ◽  
Endothelial Cell ◽  
Cell Surface ◽  
Adhesion Molecules ◽  
Surface Adhesion ◽  
Endothelial Cell Surface

Expression and role of E- and P-cadherin adhesion molecules in embryonic histogenesis. I. Lung epithelial morphogenesis

Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 263-270 ◽  
Author(s):  
Y. Hirai ◽  
A. Nose ◽  
S. Kobayashi ◽  
M. Takeichi
Keyword(s):  
Monoclonal Antibody ◽  
Cell Adhesion ◽  
Epithelial Cells ◽  
Adhesion Molecules ◽  
Lung Epithelial Cells ◽  
Early Developmental Stage ◽  
Subtle Effect ◽  
Lung Epithelial ◽  
Cell Cell

The role of Ca2+-dependent cell-cell adhesion molecules, E- and P-cadherins, in the histogenesis of mouse embryonic lung was studied. All epithelial cells of the lung express both E- and P-cadherin at the early developmental stage. P-cadherin, however, gradually disappears during development, initially from the main bronchi and eventually from all epithelial cells. When a monoclonal antibody to E-cadherin (ECCD-1) was added to monolayer cultures of lung epithelial cells, it induced a partial disruption of their cell-cell adhesion, while a monoclonal antibody to P-cadherin (PCD-1) showed a subtle effect. A mixture of the two antibodies, however, displayed a synergistic effect. We then tested the effect of the antibodies on the morphogenesis of lung primordia using an organ culture system. In control media, the explants formed typical bronchial trees. In the presence of ECCD-1, the explants grew up at the same rate as in the control, but their morphogenesis was affected. The control explants formed round epithelial lobules with an open luminal space at the tips of the bronchial trees, whereas the lobules of explants incubated with ECCD-1 tended to be flat and devoid of the luminal space. PCD-1 showed a similar but very small effect. A mixture of the two antibodies, however, showed a stronger effect: the branching of epithelia was partially suppressed and the arrangement of epithelial cells was distorted in many places. These results suggest that E- and P-cadherin have a synergistic role in the organization of epithelial cells in lung morphogenesis.

scholarly journals Flagellar adhesion in chlamydomonas induces synthesis of two high molecular weight cell surface proteins

1983 ◽  
Vol 96 (3) ◽  
pp. 589-597 ◽  
Author(s):  
WJ Snell ◽  
A Clausell ◽  
WS Moore
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Adhesion Molecules ◽  
Mating Type ◽  
Surface Proteins ◽  
Cell Wall Proteins ◽  
Intact Cells ◽  
Mating Reaction ◽  
Ionic Detergent ◽  
Flagellar Proteins

Because our previous studies (Snell, W.J., and W.S. Moore, 1980, J. Cell Biol. 84:203- 210) on the mating reaction of chlamydomonas reinhardtii showed that there was an adhesion-induced turnover of proteins whose synthesis is induced during aggregation. Analysis by SDS PAGE and autoradiography showed that proteins of 220,000 M(r) and 165, 000 M(r) (designated A(1) and A(2) respectively) consistently showed a high rate of synthesis only in flagella or flagellar membrane-enriched fractions prepared from aggregating gametes. Since the two proteins were soluble in the non-ionic detergent NP-40 and were removed from intact cells by a brief pronase treatment, it is likely that A(1) and A(2) are membrane proteins expose on the cell surface. A(1) and A(2) were each synthesized by gametes of both mating types (mt(-) and mt(+)) and synthesis of these two proteins could be detected in the normal mating reaction (wild type mt(-) and mt(+)), in mixtures of mt(-) and impotent mt(+) gametes (which could aggregate but not fuse), and in mixtures of gametes of a single mating type with isolated flagella of the opposite mating type. Cells aggregating in tunicamycin, an inhibitor of protein glycosylation, lost their adhesiveness during aggregation and did not synthesize the 220,000 M(r) protein but instead produced a protein (possibly an underglycosylated form of A(1)) of slightly lower mol wt. The 220,000 and 165,000 M(R) proteins appeared to be flagellar proteins and not cell wall proteins because A(1) and A(2) did not co-migrate with previously identified cell wall proteins, and synthesis of the two proteins could not be detected in flagella-less (bald-2) mutant cells. Analysis of the adhesive activity of sucrose gradient fraction of detergent (octyl glucoside)-solubilized flagellar membranes revealed that fractions containing A(1) and A(2) did not have detectable adhesive activity. The possibility remains that A(1) and A(2) are adhesion molecules whose activity could not be measured in the assay we used. Alternatively, the 220,000 and 165,000 M(r) proteins may be inactivated adhesion molecules or else they may be flagellar surface proteins involved only indirectly in the adhesion process.

Prognostic significance of leukopenia at the time of diagnosis in acute myeloid leukemia (AML)

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 7070-7070
Author(s):  
M. L. Arellano ◽  
E. Winton ◽  
L. Pan ◽  
L. Souza ◽  
S. Sunay ◽  
...  
Keyword(s):  
Cell Surface ◽  
Adhesion Molecules ◽  
De Novo ◽  
Risk Group ◽  
Statistical Significance ◽  
Univariate Analysis ◽  
Prognostic Significance ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Surface Adhesion

7070 Background: In contrast to the poor prognosis associated with hyperleukocytosis, the prognostic significance of leukopenia at the time of diagnosis of AML is unknown. Methods: Single institution retrospective analysis of 225 consecutive, newly diagnosed AML patients (pts), homogeneously treated between July 1996 and February 2005; and divided into 2 groups based on presenting WBC: < 2,000/uL (30) and > 2,000/uL (195). Simultaneously obtained peripheral blood and marrow blasts were analyzed for cell surface expression of CD34, cKit, CXCR4, PCAM, VLA-2, VLA-3, VLA-4, VLA-5, and FLT3 using flow cytometry. Results: Patients’ characteristics (gender, secondary vs. de novo, and cytogenetic [CTG] risk) were comparable between the 2 groups. Leukopenic AML pts were older (median 56 vs. 53 years, p = 0.02), and had lower induction complete remission [CR] rates: 63% vs. 81% (p = 0.03) by univariate analysis. Induction mortality was 0% for leukopenic and 5% for non-leukopenic pts. In primary refractory pts, median survival was longer for leukopenic (11) vs. non-leukopenic (34) pts: 137 vs. 81 d (p = 0.026). Median follow-up was 22 mos. Event-free (EFS), disease-free (DFS), and overall survivals (OS) were lower in the leukopenic group: 12 vs. 14; 14 vs. 17; and 17 vs. 19 mos, respectively; but did not reach statistical significance. By multivariate analysis, age (p < 0.0001) and CTG risk group (p < 0.0001) were independent predictors of OS, while CTG risk group predicted RFS (p < 0.0001). The level of expression of cell surface adhesion molecules on blood and marrow blasts was comparable for the 2 groups. Conclusions: AML pts presenting with leukopenia have comparable outcomes to those presenting with normal or high WBC despite a lower likelihood of achieving remission. Leukopenic AML did not have over-expression of cell surface adhesion molecules. No significant financial relationships to disclose.

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