Surface immunoglobulins of rat immunocytes: Quantitation and fate of cell-bound peroxidase-labeled antibody and Fab fragment

1974 ◽  
Vol 4 (7) ◽  
pp. 468-474 ◽  
Author(s):  
J.-C. Antoine ◽  
S. Avrameas
Keyword(s):  
Fab Fragment ◽  
Surface Immunoglobulins

scholarly journals Surface Immunoglobulins of Circulating Lymphocytes in Mouse Plasmacytoma. I. Characteristics of Lymphocyte Surface Immunoglobulins

Blood ◽  
1972 ◽  
Vol 39 (4) ◽  
pp. 453-464 ◽  
Author(s):  
Vincent Yakulis ◽  
Nirmala Bhoopalam ◽  
Sylvia Schade ◽  
Paul Heller
Keyword(s):  
Tumor Cells ◽  
Structural Properties ◽  
Surface Structures ◽  
Fab Fragment ◽  
Lymphocyte Surface ◽  
Surface Immunoglobulins ◽  
Circulating Lymphocytes

Abstract A large proportion (24-45%) of circulating lymphocytes of normal BALB/c mice was found to have surface immunoglobulins with polyclonal characteristics. Following implantation with plasmacytoma, the percentage of these normal receptor-carrying lymphocytes (RCL) was found to decrease. Concomitant with the growth of the tumors, the proportion of lymphocytes having receptors with the structural properties of the specific plasmacytoma globulin gradually increased. The antisera with which these new surface structures were demonstrated were specific for the variable portion of the Fab fragment, the idiotypic determinant of the plasmacytoma globulin. These antisera were not only raised in rabbits and rendered antiidiotypic by appropriate absorptions, but also in BALB/c mice. Evidence is presented that this alteration of receptors on the normal lymphocytes depends on the presence of tumor cells and is not caused by nonspecific absorption of the immunoglobulins to the lymphocytes.

Decisive Diagnosis of Infected Mandibular Osteoradionecrosis with a Tc-99m-labelled Anti-granulocyte Fab′-fragment

1999 ◽  
Vol 38 (07) ◽  
pp. 309-311 ◽  
Author(s):  
W. Brenner ◽  
H. Terheyden ◽  
K. H. Bohuslavizki ◽  
E. Henze ◽  
W. U. Kampen
Keyword(s):  
Blood Pool ◽  
Bone Scanning ◽  
Acute Osteomyelitis ◽  
Elevated Blood ◽  
Fab Fragment ◽  
Postoperative Changes ◽  
Three Phase ◽  
Golden Standard ◽  
Blood Pool Activity ◽  
Bone Inflammation

SummaryThe accepted golden standard for detection of inflammatory bone disease is conventional three-phase bone scanning. Hyperperfusion, a high blood-pool activity and elevated bone metabolism are typical signs for an acute osteomyelitis. However, in case of subacute, chronic inflammation, neither elevated blood flow nor high blood-pool activity may be seen. This may cause difficulties in differentiating such cases from neoplastic or postoperative changes. This case report verifies the possible advantage of immunoscintigraphy with Tc-99m-labelled antigranulocyte Fab′-fragments (LeukoScan®) in a patient with infected mandibular osteoradionecrosis, who had equivocal clinical symptomes and questionable radiographic results. LeukoScan® is shown to be more sensitive in case of subacute bone inflammation compared with three-phase bone scanning. However, acquisition of delayed images after 24 hours including SPECT is inevitable in case of negative scans during the first hours of investigation.

Anti-thrombotic Effect of a PAI-1 Inhibitor in Rats Given Endotoxin

1996 ◽  
Vol 75 (01) ◽  
pp. 118-126 ◽  
Author(s):  
T Abrahamsson ◽  
V Nerme ◽  
M Strömqvist ◽  
B Åkerblom ◽  
A Legnehed ◽  
...  
Keyword(s):  
Plasminogen Activator Inhibitor ◽  
Rat Plasma ◽  
Clot Lysis ◽  
Fibrin Deposition ◽  
Plasminogen Activator Inhibitor 1 ◽  
Fab Fragment ◽  
Dose Dependent Decrease ◽  
Pai 1

SummaryThe aim of this study was to investigate the anti-thrombotic effects of an inhibitor of the plasminogen activator inhibitor-1 (PAI-1) in rats given endotoxin. In studies in vitro, PRAP-1, a Fab-fragment of a polyclonal antibody against human PAI-1, was shown to inhibit PAI-1 activity in rat plasma as well as to stimulate clot-lysis of the euglobulin fraction derived from rat plasma. Endotoxin administered to anaesthetised rats produced a marked increase in plasma PAI-1 activity. To study fibrin formation and lysis in vivo after intravenous (i. v.) injection of the coagulant enzyme batroxobin, 125I-fibrinogen was administered to the animals. The thrombi formed by batroxobin were rapidly lysed in control animals, while the rate of lysis was markedly attenuated in rats given endotoxin. PRAP-1 was administered i.v. (bolus + infusion) to rats given endotoxin and batroxobin and the PAI-1 inhibitor caused a dose-dependent decrease in the 125I-fibrin deposition in the lungs. An immunohistochemical technique was used to confirm this decrease in density of fibrin clots in the tissue. Furthermore, PRAP-1 decreased plasma PAI-1 activity in the rats and this reduction was correlated to the decrease in lung 125I-fibrin deposition at the corresponding time point. It is concluded that in this experimental model the PAI-1 antibody PRAP-1 may indeed inhibit thrombosis in animals exposed to endotoxin.

scholarly journals The mycoplasma surface proteins MIB and MIP promote the dissociation of the antibody-antigen interaction

2021 ◽  
Vol 7 (10) ◽  
pp. eabf2403
Author(s):  
Pierre Nottelet ◽  
Laure Bataille ◽  
Geraldine Gourgues ◽  
Robin Anger ◽  
Carole Lartigue ◽  
...  
Keyword(s):  
Surface Proteins ◽  
Mycoplasma Species ◽  
Antigen Binding ◽  
Antigen Binding Site ◽  
Fab Fragment ◽  
Cryo Electron Microscopy ◽  
Antigen Complex ◽  
Antigen Interaction ◽  
Immunoglobulin Binding

Mycoplasma immunoglobulin binding (MIB) and mycoplasma immunoglobulin protease (MIP) are surface proteins found in the majority of mycoplasma species, acting sequentially to capture antibodies and cleave off their VH domains. Cryo–electron microscopy structures show how MIB and MIP bind to a Fab fragment in a “hug of death” mechanism. As a result, the orientation of the VL and VH domains is twisted out of alignment, disrupting the antigen binding site. We also show that MIB-MIP has the ability to promote the dissociation of the antibody-antigen complex. This system is functional in cells and protects mycoplasmas from antibody-mediated agglutination. These results highlight the key role of the MIB-MIP system in immunity evasion by mycoplasmas through an unprecedented mechanism, and open exciting perspectives to use these proteins as potential tools in the antibody field.

scholarly journals The Structure of the Cysteine-Rich Domain of Plasmodium falciparum P113 Identifies the Location of the RH5 Binding Site

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Ivan Campeotto ◽  
Francis Galaway ◽  
Shahid Mehmood ◽  
Lea K. Barfod ◽  
Doris Quinkert ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Binding Site ◽  
Structural Information ◽  
Blood Stage ◽  
Site Directed Mutagenesis ◽  
Effective Vaccine ◽  
Binding Region ◽  
Fab Fragment ◽  
Content Type ◽  
Blood Stage Malaria

ABSTRACT Plasmodium falciparum RH5 is a secreted parasite ligand that is essential for erythrocyte invasion through direct interaction with the host erythrocyte receptor basigin. RH5 forms a tripartite complex with two other secreted parasite proteins, CyRPA and RIPR, and is tethered to the surface of the parasite through membrane-anchored P113. Antibodies against RH5, CyRPA, and RIPR can inhibit parasite invasion, suggesting that vaccines containing these three components have the potential to prevent blood-stage malaria. To further explore the role of the P113-RH5 interaction, we selected monoclonal antibodies against P113 that were either inhibitory or noninhibitory for RH5 binding. Using a Fab fragment as a crystallization chaperone, we determined the crystal structure of the RH5 binding region of P113 and showed that it is composed of two domains with structural similarities to rhamnose-binding lectins. We identified the RH5 binding site on P113 by using a combination of hydrogen-deuterium exchange mass spectrometry and site-directed mutagenesis. We found that a monoclonal antibody to P113 that bound to this interface and inhibited the RH5-P113 interaction did not inhibit parasite blood-stage growth. These findings provide further structural information on the protein interactions of RH5 and will be helpful in guiding the development of blood-stage malaria vaccines that target RH5. IMPORTANCE Malaria is a deadly infectious disease primarily caused by the parasite Plasmodium falciparum. It remains a major global health problem, and there is no highly effective vaccine. A parasite protein called RH5 is centrally involved in the invasion of host red blood cells, making it—and the other parasite proteins it interacts with—promising vaccine targets. We recently identified a protein called P113 that binds RH5, suggesting that it anchors RH5 to the parasite surface. In this paper, we use structural biology to locate and characterize the RH5 binding region on P113. These findings will be important to guide the development of new antimalarial vaccines to ultimately prevent this disease, which affects some of the poorest people on the planet.

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