Novel CCR5 monoclonal antibodies with potent and broad-spectrum anti-HIV activities

Ji, Changhua; Brandt, Michael R.; Dioszegi, Marianna; Jekle, Andreas; Schwoerer, Stephan; Challand, Steven; Zhang, Jun; Chen, Yun; Zautke, Lisa; Achhammer, Gunthar; Baehner, Monika; Kroetz, Sandra; Heilek-Snyder, Gabrielle; Schumacher, Ralf; Cammack, Nick; Sankuratri, Surya

doi:10.1016/j.antiviral.2006.11.003

Cited by 34 publications

(43 citation statements)

References 43 publications

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“…These mAbs were further tested for HIV fusion inhibition, seven clones were further characterized, and six of them were found to be potent HIV entry inhibitors. The four most potent mAbs were fully characterized in various functional assays (20). Here, we report the epitope mapping data for these six mAbs.…”

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confidence: 99%

The Second Extracellular Loop of CCR5 Contains the Dominant Epitopes for Highly Potent Anti-Human Immunodeficiency Virus Monoclonal Antibodies

Zhang

Rao

Dioszegi

et al. 2007

Antimicrob Agents Chemother

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Six mouse anti-human CCR5 monoclonal antibodies (mAbs) that showed potent antiviral activities were identified from over 26,000 mouse hybridomas. The epitopes for these mAbs were determined by using various CCR5 mutants, including CCR5/CCR2B chimeras. One mAb, ROAb13, was found to bind to a linear epitope in the N terminus of CCR5. Strikingly, the other five mAbs bind to epitopes derived from extracellular loop 2 (ECL2). The three most potent mAbs, ROAb12, ROAb14, and ROAb18, require residues from both the N-terminal (Lys171 and Glu172) and C-terminal (Trp190) halves of ECL2 for binding; two other mAbs, ROAb10 and ROAb51, which also showed potent antiviral activities, require Lys171 and Glu172 but not Trp190 for binding. Binding of the control mAb 2D7 completely relies on Lys171 and Glu172. Unlike 2D7, the novel mAbs ROAb12, ROAb14, and ROAb18 do not bind to the linear peptide 2D7-2SK. In addition, all three mAbs bind to monkey CCR5 (with Arg at position 171 instead of Lys); however, 2D7 does not. Since five of the six most potent CCR5 mAbs derived from the same pool of immunized mice require ECL2 as epitopes, we hypothesize that CCR5 ECL2 contains the dominant epitopes for mAbs with potent antiviral activities. These dominant epitopes were found in CCR5 from multiple species and were detected in large proportions of the total cell surface CCR5. mAbs recognizing these epitopes also showed high binding affinity. A homology model of CCR5 was generated to aid in the interpretation of these dominant epitopes in ECL2.

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confidence: 99%

The Second Extracellular Loop of CCR5 Contains the Dominant Epitopes for Highly Potent Anti-Human Immunodeficiency Virus Monoclonal Antibodies

Zhang

Rao

Dioszegi

et al. 2007

Antimicrob Agents Chemother

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“…It is possible that some of the MAb staining differences reflect the presence of CCR5 antigenic variants created by structural variations or posttranslational modifications. Of note, among the various MAbs that bind to CCR5, only a few can inhibit HIV-1 infection, irrespective of how well they stain the same cells (23,24,28,29,40).In this study, we quantified the binding properties of 10 CCR5 MAbs to various epitopes and assessed whether parental and inhibitor-resistant clones representative of the V3 and FP resistance pathways use distinct CCR5 variants for entry. Different antigenic forms of CCR5 were seen on the surfaces of U87-CD4-CCR5 cells and primary CD4 ϩ T cells.…”

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Multiple CCR5 Conformations on the Cell Surface Are Used Differentially by Human Immunodeficiency Viruses Resistant or Sensitive to CCR5 Inhibitors

Berro

Klasse

Lascano

et al. 2011

J Virol

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Resistance to small-molecule CCR5 inhibitors arises when HIV-1 variants acquire the ability to use inhibitor-bound CCR5 while still recognizing free CCR5. Two isolates, CC101.19 and D1/85.16, became resistant via four substitutions in the gp120 V3 region and three in the gp41 fusion peptide (FP), respectively. The binding characteristics of a panel of monoclonal antibodies (MAbs) imply that several antigenic forms of CCR5 are expressed at different levels on the surfaces of U87-CD4-CCR5 cells and primary CD4؉ T cells, in a cell-typedependent manner. CCR5 binding and HIV-1 infection inhibition experiments suggest that the two CCR5 inhibitor-resistant viruses altered their interactions with CCR5 in different ways. As a result, both mutants became generally more sensitive to inhibition by CCR5 MAbs, and the FP mutant is specifically sensitive to a MAb that stains discrete cell surface clusters of CCR5 that may correspond to lipid rafts. We conclude that some MAbs detect different antigenic forms of CCR5 and that inhibitor-sensitive and -resistant viruses can use these CCR5 forms differently for entry in the presence or absence of CCR5 inhibitors.The small-molecule CCR5 inhibitors maraviroc (MVC) and vicriviroc (VVC) are, or have been, used to treat human immunodeficiency virus type 1 (HIV-1) infection. They bind in the transmembrane helices and stabilize CCR5 in a conformation the viral Env complex cannot use efficiently (14,26,47). Resistant viruses usually gain the ability to enter cells via inhibitor-bound CCR5 while retaining the use of free CCR5 (46, 57). Virus-CCR5 binding involves interactions between the Tyr-sulfated N terminus (NT) and the second extracellular loop (ECL2) of the coreceptor and the 4-stranded bridging sheet and V3 region of the gp120 glycoprotein, respectively (20,21). In the most common genetic route to resistance, multiple sequence changes in V3 make the virus more dependent on the CCR5 NT (4,7,27,(37)(38)(39)55). A much rarer pathway involves changes in the fusion peptide (FP) of the gp41 protein, but the resistance mechanism is unknown (3). These pathways were followed when resistant isolates CC101.19 and D1/85.16 were derived from CC1/85 under selection by two similar inhibitors, AD101 and VVC, in peripheral blood mononuclear cells (PBMCs); the most critical resistance-associated substitutions in the escape mutant viruses were four in V3 and three in the FP (27,33). In this study, we used infectious Env chimeric clones, Res-4V3 derived from CC101.19 and Res-3FP from D1/85.16, together with the parental clones Par-4V3 and Par-3FP, derived from CC1/85, which were chosen based on sequence similarities with Res-4V3 and Res-3FP (7).The HIV-1 coreceptors CCR5 and CXCR4 exist in heterogeneous forms (6, 29), influenced by factors such as posttranslational modifications, coupling to G proteins, and the lipid environment (5,8,15,34,35). CCR5 monoclonal antibodies (MAbs) can vary considerably in how they stain different cell types in a way that is not always explained by CCR5 expression levels (1...

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“…Current therapeutics under development, such as the anti-CD4 antibody ibalizumab (formerly known as TNX-355) (10,12,14,22) and the anti-CCR5 antibodies PRO 140 and HGS004 (14,23), have shown efficacy against viral infections in vitro and in clinical trials (11,15,16,24,25). We recently described two CCR5 antibodies with high antiviral activity in vitro (16,18,40): RoAb13, which binds to the NTD of CCR5, and MAb3952, which recognizes extracellular domain 2 (ECL-2) of CCR5 (16).…”

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Development of Tetravalent, Bispecific CCR5 Antibodies with Antiviral Activity against CCR5 Monoclonal Antibody-Resistant HIV-1 Strains

Schanzer

Jekle

Nezu

et al. 2011

Antimicrob Agents Chemother

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In this study, we describe novel tetravalent, bispecific antibody derivatives that bind two different epitopes on the HIV coreceptor CCR5. The basic protein formats that we applied were derived from Morrison-type bispecific antibodies: whole IgGs to which we connected single-chain antibodies (scFvs) via (Gly 4 Ser) n sequences at either the C or N terminus of the light chain or heavy chain. By design optimization, including disulfide stabilization of scFvs or introduction of 30-amino-acid linkers, stable molecules could be obtained in amounts that were within the same range as or no less than 4-fold lower than those observed with monoclonal antibodies in transient expression assays. In contrast to monospecific CCR5 antibodies, bispecific antibody derivatives block two alternative docking sites of CCR5-tropic HIV strains on the CCR5 coreceptor. Consequently, these molecules showed 18-to 57-fold increased antiviral activities compared to the parent antibodies. Most importantly, one prototypic tetravalent CCR5 antibody had antiviral activity against virus strains resistant to the single parental antibodies. In summary, physical linkage of two CCR5 antibodies targeting different epitopes on the HIV coreceptor CCR5 resulted in tetravalent, bispecific antibodies with enhanced antiviral potency against wild-type and CCR5 antibodyresistant HIV-1 strains.

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Novel CCR5 monoclonal antibodies with potent and broad-spectrum anti-HIV activities

Cited by 34 publications

References 43 publications

The Second Extracellular Loop of CCR5 Contains the Dominant Epitopes for Highly Potent Anti-Human Immunodeficiency Virus Monoclonal Antibodies

The Second Extracellular Loop of CCR5 Contains the Dominant Epitopes for Highly Potent Anti-Human Immunodeficiency Virus Monoclonal Antibodies

Multiple CCR5 Conformations on the Cell Surface Are Used Differentially by Human Immunodeficiency Viruses Resistant or Sensitive to CCR5 Inhibitors

Development of Tetravalent, Bispecific CCR5 Antibodies with Antiviral Activity against CCR5 Monoclonal Antibody-Resistant HIV-1 Strains

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