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Immunocytochemical Detection Systems
Published in Lars-Inge Larsson, Immunocytochemistry: Theory and Practice, 2020
Protein A is a protein of the cell wall of Staphylococcus aureus. It reacts with the Fc region of immunoglobulins from many (but not all) species. In addition, some antibodies also may bind protein A by their Fab region, as shown for two mouse monoclonal antibodies by Young et al.388 This Fab-binding phenomenon could possibly explain some disappointing results with protein A double-staining techniques, as will be discussed in Chapter 5, Section I.D.3. Not all four subclasses of human IgG bind protein A. Moreover, the mouse IgGl subclass, rat IgG subclasses, and goat IgG bind protein A poorly or not at all. Recently, however, a new protein, protein G, was isolated from streptococci and was found to bind all four human IgG subclasses as well as IgG of several other species.390 Thus, protein G could be a very useful substitute or alternative to protein A, but has not yet been immunocytochemically tested.
The Airway and Vasoactive Intestinal Peptide Autoantibodies and Receptors
Published in Devendra K. Agrawal, Robert G. Townley, Inflammatory Cells and Mediators in Bronchial Asthma, 2020
The binding of VIP by plasma from healthy and asthmatic subjects was largely due to the presence of IgG-type antibodies. The VIP-binding activity was precipitated by antiserum against human IgG; it coeluted with authentic immunoglobulins from anion exchange, gel filtration, and immobilized protein-G-columns, and an Fab2 fragment capable of binding VIP was produced by treatment of the binding factor with pepsin.16,17
Radiotracer Labeling of Brain Slices
Published in Avital Schurr, Benjamin M. Rigor, BRAIN SLICES in BASIC and CLINICAL RESEARCH, 2020
George C. Newman, Frank E. Hospod, Clifford S. Patlak, Hui Qi
The tissue wet weight is presently measured directly at the end of the incubation. We previously calculated wet weight by multiplying the measured total slice protein by the protein/wet weight ratio of 84 mg protein/g tissue.6 However, this latter method has the disadvantage of being insensitive to changes in slice water content that may vary with experimental conditions, especially for experiments involving models of ischemia, so we now prefer to use the wet weight measured at the conclusion of the experiment. Preparation of samples for analysis of radioactivity by autoradiography have been described previously in considerable detail.1
Gastrin-releasing peptide receptor agonists and antagonists for molecular imaging of breast and prostate cancer: from pre-clinical studies to translational perspectives
Published in Expert Review of Molecular Diagnostics, 2022
Joana Gorica, Maria Silvia De Feo, Luca Filippi, Viviana Frantellizzi, Orazio Schillaci, Giuseppe De Vincentis
GRPR, also known as bombesin receptor subtype 2, is a 384 amino acid G protein-coupled receptor whose endogenous ligand is a gastrin-releasing peptide. The protein G is characterized by seven transmembrane domains that form the ligand binding pocket (Figure 1). GRPR has various physiologic functions, such as the stimulation of smooth muscle contraction, release of gastrointestinal hormones, exocrine secretion in the pancreas, colon, and stomach, and cell growth proliferation. More importantly, in humans, GRPR is highly expressed in stomach, pancreas, adrenal glands, and brain. Abnormal expression of GRPR has been detected in various tumors, such as prostate and breast (62% of cancers express it), colon (76–100%), lung cancer, gliomas, meningiomas, pancreatic cancer, renal cancer, head and neck cancer, neuroblastomas, etc. [10].
Extended plasma half-life of albumin-binding domain fused human IgA upon pH-dependent albumin engagement of human FcRn in vitro and in vivo
Published in mAbs, 2021
Simone Mester, Mitchell Evers, Saskia Meyer, Jeannette Nilsen, Victor Greiff, Inger Sandlie, Jeanette Leusen, Jan Terje Andersen
As an alternative to albumin itself, small albumin-binding modalities that can associate with endogenous albumin upon administration, such as albumin-binding peptides,32,33 albumin-binding antibody fragments34–36 and albumin-binding domains (ABDs) derived from bacteria, can be included in fusion protein drugs.37–45 Examples are Nanobodies derived from camelids,32 and designed ankyrin repeat proteins (DARPins),33 both selected for binding with nM affinity to albumin from different species. Other examples are single variable antibody domains with albumin specificity (AlbudAb),34–36 and ABDs derived from gram-positive bacteria displaying such proteins on their surface to camouflage and evade the immune system of the host.37–41 ABDs that bind albumin from different species,42–45 have been explored as biotechnological tools for purification and interaction analyses. Importantly, they have also been explored as fusion partners to extend the plasma half-life of fused proteins by indirect targeting of FcRn.46–51 The most-studied ABD, derived from Streptococcal protein G,37,52–55 has been engineered to strongly bind to human albumin at both neutral and mildly acidic pH.56
Blockade of ErbB2 and PD-L1 using a bispecific antibody to improve targeted anti-ErbB2 therapy
Published in OncoImmunology, 2019
Deepak Mittal, Dipti Vijayan, Joost Neijssen, Joost Kreijtz, Maurice M. J. M. Habraken, Hans Van Eenennaam, Andrea Van Elsas, Mark J. Smyth
Antibodies (all mmIgG2a and variants thereof generated for this study) were purified by protein A affinity chromatography (MabSelect SuRe; GE Health Care), dialyzed overnight to PBS, and filter-sterilized over 0.2-µM filters. Alternatively, antibodies were purified by protein G affinity chromatography (GE Health Care). The purity was determined by SDS-PAGE/CE-SDS and the concentration was measured by absorbance at 280 nm (specific extinction coefficients were calculated for each protein). Batches of purified antibody were tested by high-performance size-exclusion chromatography (HP-SEC) to determine the presence of aggregates or degradation products. Purified antibodies were stored at 2–8°C. Endotoxin levels of batches used in vivo were below 0.2 endotoxin units/mg IgG. Batches were visually inspected before use and in case of precipitates the samples were centrifuged and the concentration was determined.