Antibody and HIV-1 gpl20 recognition of CD4 undermines the concept of mimicry between antibodies and receptors

Davis, Simon J.; Schockmel, Gérard A.; Somoza, Chamorro; Buck, David; Healey, Dan; Rieber, Ernst Peter; Reiter, Christian; Williams, Alan F.

doi:10.1038/358076a0

Cited by 67 publications

(32 citation statements)

References 31 publications

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“…The fact that mutagenesis of this site did not affect ligand-binding supports the idea that ligand-competitive mAbs rarely mimic the binding of ligand to the receptor. This was found to be the case in the analysis of a large number of mAbs against CD4 which block gp120 binding (Davis et al, 1992).…”

Section: Discussionmentioning

confidence: 99%

The Extracellular Domain of the Epidermal Growth Factor Receptor

Brown

Debanne

Grothé

et al. 1994

European Journal of Biochemistry

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The binding of epidermal growth factor (EGF) or an EGF-like growth factor to the EGF receptor is the initial event which leads to receptor activation, and consequently the induction of cell growth. In order to study this binding interaction in detail, we produced the extracellular domain of the EGF receptor (EGFR) using the baculovirus expression system. Affinity-labeling and Western-blot analyses revealed that the baculovirus-infected insect cells secrete active EGFR extracellular domain relatively efficiently, however a significant amount of inactive EGFR extracellular domain is retained within the cells. The apparent dissociation constant (&) of the secreted EGFR extracellular domain for EGF and transforming growth factor a (TGF-a), as determined using an immobilized receptor binding assay, was approximately 200 nM. Interestingly, this Kd value is 30-40-fold lower than that of the full-length EGFR derived from detergent-solubilized A431 cell membranes. The stoichiometry of binding of the EGFR extracellular domain to EGF and TGF-a was examined by band-shift analysis on non-denaturing PAGE and was estimated to be 1 : 1. We have also shown, using sedimentation equilibrium analysis, that ligand binding induces significant dimerization of the EGFR extracellular domain. Finally, we carried out site-specific mutagenesis on the EGFR extracellular domain in order to define the ligand-binding region. We identified amino acid residues which are close to the binding site since they are common to the epitopes of several ligand-competitive monoclonal antibodies. However, these residues do not contribute directly to ligand binding since the affinity of the mutated EGFR extracellular domain for EGF and TGF-a was unaffected.Binding of epidermal growth factor (EGF) to the extracellular domain of its 170-kDa receptor (EGFR) leads to activation of the receptor cytoplasmic tyrosine kinase, substrate phosphorylation and ultimately mitogenesis (reviewed by Carpenter and Cohen, 1990;Ullrich and Schlessinger, 1990). Fundamental questions concerning the initial EGFEGFR interaction which leads to receptor activation can be addressed using a truncated form of the EGFR which consists of only the extracellular ligand-binding domain of the receptor. We have utilized the baculovirus expression system to produce large quantities of the extracellular domain and this has enabled us to study the affinity and stoichiometry of ligand binding, ligand-induced dimerization, as well as to attempt to identify receptor residues which are critical for ligand binding.In relation to the issue of affinity, the dissociation constant (Kd) of the soluble EGFR extracellular domain for EGF

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Section: Discussionmentioning

confidence: 99%

The Extracellular Domain of the Epidermal Growth Factor Receptor

Brown

Debanne

Grothé

et al. 1994

European Journal of Biochemistry

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“…For example, a recent article claimed to have "undermined" the concept of mimicry between antibodies, receptors, and their ligands (33). The criticism was applied particularly to mimicry by antibodies that bear no structural similarity to the immunizing ligand, which was described as a "chance event of incalculable frequency" (34).…”

Section: Discussionmentioning

confidence: 99%

Idiotypic mimicry and the assembly of a supramolecular structure: an anti-idiotypic antibody that mimics taxol in its tubulin-microtubule interactions.

Leu

Chen²,

Diamanduros³

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

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Taxol, rii y extrced fro the bark of the western yew, Taxus brenfolia, is reportedly the first of a new class of anti-cancer agent. It Taxol, reportedly the first of a new class of anti-cancer agents, was originally extracted from the bark of the western yew, Taxus brevifolia (1). In vivo, it prevents the disassembly of microtubules, causing the arrest of cells at the G2/M step of the cell cycle (2). Its mechanism differs from that of other anti-cancer agents that have tubulin as their target, such as colchicine, podophyllotoxin, or vinblastine, which inhibit tubulin polymerization (3). The site of action of taxol on tubulin is being investigated in several laboratories. Photoaffinity-labeling experiments implicate the N-terminal region of (3-tubulin as the site of attachment (4, 5).With the aim of using immunological techniques to investigate the action of taxol, we sought to prepare an anti-idiotypic antibody that mimics taxol, using an auto-anti-idiotypic strategy (6, 7). We have succeeded in obtaining an antibody, 82H, that, as intact antibody or Fab fiagment, mimics taxol in its tubulinmicrotubule interactions to the extent that it can cause tubulin to assemble into microtubules. MATERIALS AND METHODSPreparation of and Screening for Anti-Idiotypic Antibodies. The object was to screen for monoclonal antibodies that showed taxol-inhibitable binding to Fab fragments ofaffinitypurified rabbit anti-taxol antibody R585 (8).Preparation of Fab fragments of R585. Rabbit anti-taxol antiserum R585 (8) was affinity-purified as follows. Two affinity columns were prepared. Either 10 mg of bovine serum albumin (BSA) or 10 mg of taxol covalently linked to rabbit serum albumin (taxol-RSA) (8) was dissolved in 1 ml of 0.1 M 2-(N-morpholino)-ethanesulfonic acid (Mes) buffer (pH 4.8) and added to 2 ml of Affi-Gel 10 (Bio-Rad). The mixtures were rocked gently overnight at 40C. The gels were then washed with several column volumes of phosphatebuffered saline (PBS, pH 7.3) and with 0.2 M glycine hydrochloride buffer (pH 2.5) and then equilibrated with PBS. Six milliliters of R585 antiserum was first recirculated through the taxol-RSA-Affi-Gel 10 column overnight at 40C at a rate of0.2 ml/min. The column was then extensively washed with PBS at a rate of 1.0 ml/min to remove all nonspecifically bound proteins. The antibodies were then eluted with 0.2 M glycine hydrochloride (pH 2.5) at a rate of 0.5 ml/min. The eluted antibodies were immediately neutralized with 2 M Tris base and dialyzed against PBS at 40C overnight. On the following day, the eluted antibodies were recycled through the BSA-Affi-Gel 10 column at 40C overnight to remove BSA-binding antibodies. The effluent, which contained antitaxol antibodies in PBS, was collected and concentrated by a Centriprep-10 concentrator (Amicon) to a volume of 1-2 ml.Fab fragments were prepared from the affinity-purified antibodies as described (9).Screening for anti-idiotypic antibodies. A competitive ELISA was used to assay for taxol-inhibitable binding to the Fab fiagments of ...

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“…One of them, which has not been much considered as yet, consists of exploiting the capacity of some antibody to mimic, at least to some extent, a receptor or an ion channel. Previous studies have revealed that some monoclonal antibodies raised against receptor-specific ligands share structural and/or functional properties with receptors (3)(4)(5)(6). Evidently, such receptor-mimicking antibodies constitute interesting templates to approach the structure of a ligand binding site on its receptor.…”

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confidence: 99%

The Functional Architecture of an Acetylcholine Receptor-mimicking Antibody

Mérienne

Germain

Zinn‐Justin

et al. 1997

Journal of Biological Chemistry

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M␣2-3 is a monoclonal antibody that partially mimics the nicotinic acetylcholine receptor (AChR). Its threedimensional structure has been previously predicted by molecular modeling, suggesting that 29 complementarity determining region (CDR) residues and 2 framework residues are exposed to solvent. To identify the antibody residues that bind to the antigen, i.e. snake toxin that binds specifically to AChR, we (i) produced the scFv form of M␣2-3 fused to alkaline phosphatase, in the periplasmic space of Escherichia coli; (ii) submitted approximately 75% of exposed residues of the fused scFv to individual or combined mutations, and (iii) identified the residues whose mutations affect scFv binding to the toxin, using a sensitive enzyme-linked immunosorbent assay. 11 critical residues were identified, including 8 heavy chain residues, 2 framework residues, and 1 light chain residue. They cover a surface of approximately 800 Å 2 , with a subset of most critical residues (VHD31, VHY32, and VHG101) and several aromatic residues. This functional architecture not only constitutes a plausible complementary binding surface for the snake toxin but also offers a structural basis to ultimately understand the capacity of the antibody to partially mimic AChR.

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Antibody and HIV-1 gpl20 recognition of CD4 undermines the concept of mimicry between antibodies and receptors

Cited by 67 publications

References 31 publications

The Extracellular Domain of the Epidermal Growth Factor Receptor

The Extracellular Domain of the Epidermal Growth Factor Receptor

Idiotypic mimicry and the assembly of a supramolecular structure: an anti-idiotypic antibody that mimics taxol in its tubulin-microtubule interactions.

The Functional Architecture of an Acetylcholine Receptor-mimicking Antibody

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