scholarly journals Inhibition of the formation of the complement membrane-attack complex by a monoclonal antibody to the complement component C8 α subunit

1989 ◽  
Vol 264 (3) ◽  
pp. 933-936 ◽  
Author(s):  
A Abraha ◽  
J P Luzio
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Membrane Attack Complex ◽  
Complement Component ◽  
Alpha Subunit ◽  
Α Subunit ◽  
Complement Component C8

The effect of nine monoclonal antibodies to complement component C8 on the interaction of C9 with preformed cell-surface C5b-8 complexes and on the functional insertion of C8 into the membrane-attack complex (MAC) was investigated. None of the antibodies prevented C9 insertion into a preformed C5b-8 complex. One antibody (F1) directed to the C8 alpha subunit clearly inhibited formation of a functional MAC. It is proposed that this antibody prevents the C8 alpha subunit unfolding and distorting the bilayer to allow C9 insertion.

scholarly journals The preparation and characterization of monoclonal antibodies to human complement component C8 and their use in purification of C8 and C8 subunits

1988 ◽  
Vol 251 (1) ◽  
pp. 285-292 ◽  
Author(s):  
A Abraha ◽  
B P Morgan ◽  
J P Luzio
Keyword(s):  
Monoclonal Antibodies ◽  
Polyacrylamide Gel Electrophoresis ◽  
Antigenic Site ◽  
Complement Component ◽  
Biologically Active ◽  
Alpha Subunit ◽  
Human Complement ◽  
Competitive Binding Assay ◽  
Complement Component C8 ◽  
Human Complement Component

1. Ten mouse monoclonal antibodies to human complement component C8 were prepared. It was found that six of these antibodies reacted with the alpha-subunit, two with the beta-subunit and two with the gamma-subunit, when assessed by immunoblotting after separation of C8 subunits by SDS/polyacrylamide-gel electrophoresis. 2. Epitope analysis of the ten monoclonal antibodies in a competitive binding assay showed that the six antibodies to the alpha-subunit could be classified in four overlapping epitope groups. The antibodies to the beta- and gamma-subunits bound to a single antigenic site on each, but also cross-reacted with the antigenic sites on the alpha-subunit. 3. Monoclonal anti-C8 immunoaffinity columns were used to purify C8 from fresh human plasma and to prepare C8-depleted serum. Immunoaffinity purified C8 was biologically active when assessed by using haemolysis assays of sheep and rabbit erythrocytes. 4. Salt elution was used to purify either alpha gamma- or beta-subunits when C8 was respectively bound to an anti-beta or anti-alpha immunoaffinity column. The purified subunits reconstituted C8-depleted serum when added together in a haemolysis assay.

A scale associated protein of Apedinella radians (Pedinellophyceae) and its possible role in the adhesion of surface components

1993 ◽  
Vol 104 (2) ◽  
pp. 391-398
Author(s):  
A. Koutoulis ◽  
M. Ludwig ◽  
R. Wetherbee
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cell Membrane ◽  
Cell Surface ◽  
Immunofluorescence Microscopy ◽  
Endomembrane System ◽  
Thin Sections ◽  
Specific Location ◽  
Whole Cells

Monoclonal antibodies have been generated against cell surface components of the unicellular phytoflagellate Apedinella radians (Pedinellophyceae). One monoclonal antibody, designated Arg 1E5/1B1, labels a scale associated protein (SAP) of 145 kDa. Immunofluorescence microscopy of whole cells as well as immunoelectron microscopy of whole cell mounts and thin sections using Arg 1E5/1B1 have shown that the SAP is located on the proximal surface of body scales and spine-scales. Its specific location suggests that the SAP may play a role in the adhesion of these surface components to the cell membrane and/or to one another. The potential of monoclonal antibody Arg 1E5/1B1 as a tool to study cell surface morphogenesis and the role of the endomembrane system in A. radians is discussed.

Immunotherapy of Mouse Leukemia with Monoclonal Antibodies Directed against Type-C Virus Structural Proteins

1984 ◽  
Vol 70 (1) ◽  
pp. 9-16
Author(s):  
Mauro Boiocchi ◽  
Piera Mondellini
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Therapeutic Effect ◽  
Structural Proteins ◽  
Leukemia Cells ◽  
Envelope Glycoproteins ◽  
Mouse Leukemia ◽  
Type C

The monoclonal antibody A6, isolated during a study on the natural immunoresponse of BALB/c mice against leukemia cells (4), reacts with the envelope glycoproteins gp70 of the MuLV and with the cell surface of the SL2 AKR leukemia. In the present paper, we describe the in vivo immunotherapeutic effect exerted by the A6 monoclonal antibody on the growth of the transplanted leukemia SL2. The greater therapeutic effect observed when the A6 was used with exogenous complement cooperation suggests that the immunotherapeutic activity is mediated by C'-dependent cytotoxicity.

scholarly journals Anti-Mac-1 selectively inhibits the mouse and human type three complement receptor.

1982 ◽  
Vol 156 (4) ◽  
pp. 1000-1009 ◽  
Author(s):  
D I Beller ◽  
T A Springer ◽  
R D Schreiber
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Polymorphonuclear Leukocytes ◽  
Specific Cell ◽  
Complement Receptor ◽  
Murine Macrophage ◽  
Differentiation Antigen ◽  
Human Macrophages ◽  
Specific Cell Surface

Anti-Mac-1 (M1/70), a rat monoclonal antibody that reacts with mouse and human macrophages, polymorphonuclear leukocytes (PMNL), and natural killer cells, selectively inhibited complement receptor-mediated rosetting by murine macrophages and human PMNL. Preincubation of macrophages with anti-Mac-1 inhibited formation of rosettes with sheep erythrocytes bearing IgM antibody and murine C3 fragments. No inhibition was observed when other monoclonal antibodies that react with macrophages (such as anti-Ly5, anti-H-2, or anti-pan-leukocyte) were tested at 10-fold higher concentrations. Anti-Mac-1 did not affect macrophage Fc receptor-mediated rosetting. Erythrocytes bearing homogeneous human C3 fragments C3b (EC3b) or C3bi (EC3bi) were used to test the specificity of the murine macrophage and human PMNL complement receptor inhibited by anti-Mac-1. In both cases, anti-Mac-1 inhibited CR3-mediated rosetting of EC3bi but not CR1-dependent rosetting of EC3b. The results show that Mac-1 is either identical to CR3 or closely associated with CR3 function. This is one of the first cases in which a monoclonal antibody-defined differentiation antigen has been associated with a specific cell surface function.

The alpha 2 beta 1 integrin regulates collagen-mediated MDCK epithelial membrane remodeling and tubule formation

1995 ◽  
Vol 108 (6) ◽  
pp. 2487-2498 ◽  
Author(s):  
R. Schwimmer ◽  
G.K. Ojakian
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Apical Membrane ◽  
Apical Cell ◽  
Collagen Gel ◽  
Integrin Subunit ◽  
Membrane Remodeling ◽  
Tubule Formation ◽  
Beta 1 Integrin

Previous studies have demonstrated that incubation of MDCK cell epithelial cysts in collagen gel induced a reversal in cell surface polarity that was regulated by beta 1 integrins. Further experiments were done to identify the specific collagen binding integrin involved by applying collagen gel overlays to the apical membrane of subconfluent MDCK monolayers. Cell surface levels of the apical membrane glycoprotein gp135 were monitored by ELISA to quantitate the extent of collagen-mediated membrane remodeling. After an 8 hour incubation with collagen, there was a 35% reduction in gp135 while the cell surface levels of the alpha 2, alpha 3 and beta 1 integrin subunits were not affected. Immunofluorescence microscopy confirmed the loss of gp135 from selected regions of the apical cell surface while the alpha 2 and beta 1 integrin subunits were distributed in small clusters over the entire apical membrane in both control and collagen-treated monolayers. Collagen-mediated loss of gp135 was inhibited by monoclonal antibodies which recognize either the alpha 2 or beta 1 integrin subunits but not by a monoclonal antibody against the alpha 6 beta 1 integrin. These results demonstrated that remodeling of the apical membrane had occurred, allowing the selective retention of beta 1 integrins but not gp135. They were supported by the observation that collagen-mediated loss of apical membrane microvilli was inhibited by the monoclonal antibody against the alpha 2 integrin subunit. Incubation of confluent monolayers with collagen gel induced the formation of polarized epithelial tubules within 16 hours. Epithelial tubule biogenesis was completely inhibited by monoclonal antibodies against either the alpha 2 or beta 1 integrin subunits, providing strong evidence that the alpha 2 beta 1 integrin is essential for collagen-mediated epithelial membrane remodeling and tubule formation.

Monoclonal antibodies in dermatologic research *udies with a unique cell-surface antigen defined specifically for keratinocytes by a monoclonal antibody

1985 ◽  
Vol 7 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Jo-David Fine ◽  
Stephen M. Breathnach ◽  
Patricia A. Fox ◽  
Gabrielle R. Neises ◽  
John R. Stanley ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Surface Antigen ◽  
Cell Surface Antigen ◽  
Unique Cell

scholarly journals Identification and Expression of a Mycoplasma gallisepticum Surface Antigen Recognized by a Monoclonal Antibody Capable of Inhibiting Both Growth and Metabolism

2000 ◽  
Vol 68 (6) ◽  
pp. 3186-3192 ◽  
Author(s):  
Shigeto Yoshida ◽  
Ayumi Fujisawa ◽  
Yoshinari Tsuzaki ◽  
Shuji Saitoh
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Genomic Dna ◽  
Mycoplasma Gallisepticum ◽  
Expression Library ◽  
Gene Encoding ◽  
Antigenic Proteins ◽  
Orf6 Gene

ABSTRACT In order to identify antigenic proteins of Mycoplasma gallisepticum, monoclonal antibodies (MAbs) against virulentM. gallisepticum R strain were produced in mice. MAb 35A6 was selected for its abilities to inhibit both growth and metabolism ofM. gallisepticum in vitro. The MAb recognized a membrane protein with an apparent molecular mass of 120 kDa. The corresponding gene, designated the mgc3 gene, was cloned from an M. gallisepticum genomic DNA expression library and sequenced. The mgc3 gene is a homologue of the ORF6 gene encoding 130-kDa protein in the P1 operon of M. pneumoniae and is localized downstream of the mgc1 gene, a homologue of the P1 gene. To assess the characteristics of MGC3 protein, all 10 TGA codons in the mgc3 gene, which encode a tryptophan in the Mycoplasma species, were replaced with TGG codons, and recombinant fowlpox viruses (FPV) harboring the altered mgc3 gene were constructed. One of the recombinant FPVs was improved to express MGC3 protein on the cell surface in which the signal peptide of MGC3 protein was replaced with one from Marek's disease virus gB. These results should provide the impetus to develop a vaccine based on MGC3 protein which can induce antibodies with both growth inhibition and metabolic-inhibition activities using a recombinant FPV.

Quantitative expression of epitopes defined by murine monoclonal antibodies on DR molecules from different HLA haplotypes

1985 ◽  
Vol 5 (10-11) ◽  
pp. 923-931 ◽  
Author(s):  
Michelle Letarte ◽  
Jane Addis ◽  
Sonia Iturbe ◽  
Dieter Petsche
Keyword(s):  
Monoclonal Antibody ◽  
Flow Cytometry ◽  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Class Ii ◽  
Human Class ◽  
Quantitative Expression ◽  
Hla Dr ◽  
Hla Haplotypes ◽  
Murine Monoclonal Antibodies

Monoclonal antibodies 50D6 and 2Ir5, reactive with human class II molecules, were analyzed quantitatively by flow cytometry and cellular radioimmunoassay for their binding to cells of different HLA-DR types. Monoclonal antibody 50D6 bound equally to cells of all DR types tested except DR7, where no reactivity was observed. Monoclonal antibody 2Ir5 was reactive with all cells. However, the percentage of DR molecules at the cell surface expressing 2Ir5 epitope varied with the DR type and increased as follows: DR3 = DR7 < DR2 < DR5 < DR4 < DR1. MAb 50D6 reacted with an epitope spatially related to but distinct from the 2lw4 epitope present on all DR molecules. The 50D6 epitope was shown to be present on isolated DR1 molecules.

The structure and function of complement component C8 investigated with monoclonal antibodies

1987 ◽  
Vol 15 (4) ◽  
pp. 649-650 ◽  
Author(s):  
AREFAINE ABRAHA ◽  
CAROLINE A. SEWRY ◽  
ANTHONY K. CAMPBELL ◽  
J. PAUL LUZIO
Keyword(s):  
Monoclonal Antibodies ◽  
Structure And Function ◽  
Complement Component ◽  
And Function ◽  
Complement Component C8

Use of a monoclonal antibody recognizing a cell surface determinant to distinguish prestalk and prespore cells of Dictyostelium discoideum slugs

Development ◽  
1985 ◽  
Vol 88 (1) ◽  
pp. 15-24
Author(s):  
Marianne Krefft ◽  
Ludwig Voet ◽  
James H. Gregg ◽  
Keith L. Williams
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Antigenic Determinant ◽  
Developmental Stages ◽  
Double Labelling ◽  
Spore Surface ◽  
Cell Sorter ◽  
A Cell

Double labelling experiments on Dictyostelium discoideum cells at different developmental stages were carried out using monoclonal antibodies MUD1 (prespore specific), MUD9 (strong label on prestalk and anterior-like cells) and a fluorescence-activated cell sorter. The monoclonal antibody MUD9, which recognizes the surface of prestalk and anterior-like cells strongly and prespore cells weakly, is also present on the surface of vegetative amoebae and on mature stalk cells but not on the spore surface. Sharing of an antigenic determinant between vegetative, prestalk and anterior-like cells is consistent with these cells being ‘less differentiated’ than prespore cells.

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