scholarly journals Epitope Mapping of Ibalizumab, a Humanized Anti-CD4 Monoclonal Antibody with Anti-HIV-1 Activity in Infected Patients

2010 ◽  
Vol 84 (14) ◽  
pp. 6935-6942 ◽  
Author(s):  
Ruijiang Song ◽  
David Franco ◽  
Chia-Ying Kao ◽  
Faye Yu ◽  
Yaoxing Huang ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Viral Entry ◽  
Underlying Mechanism ◽  
Mhc Ii ◽  
Humanized Monoclonal Antibody ◽  
Class Ii Mhc ◽  
Unique Specificity ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACT Ibalizumab is a humanized monoclonal antibody that binds human CD4, the primary receptor for human immunodeficiency virus type 1 (HIV-1). With its unique specificity for domain 2 of CD4, this antibody potently and broadly blocks HIV-1 infection in vitro by inhibiting a postbinding step required for viral entry but without interfering with major histocompatibility complex class II (MHC-II)-mediated immune function. In clinical trials, ibalizumab has demonstrated anti-HIV-1 activity in patients without causing immunosuppression. Thus, a characterization of the ibalizumab epitope was conducted in an attempt to gain insight into the underlying mechanism of its antiviral activity as well as its safety profile. By studying mouse/human chimeric CD4 molecules and site-directed point mutants of CD4, amino acids L96, P121, P122, and Q163 in domain 2 were found to be important for ibalizumab binding, with E77 and S79 in domain 1 also contributing. All these residues appear to cluster on the interface between domains 1 and 2 of human CD4 on a surface opposite the site where gp120 and the MHC-II molecule bind on domain 1. Separately, the epitope of M-T441, a weakly neutralizing mouse monoclonal antibody that competes with ibalizumab, was localized entirely within domain 2 on residues 123 to 125 and 138 to 140. The results reported herein not only provide an appreciation for why ibalizumab has not had significant adverse immunological consequences in infected patients to date but also raise possible steric hindrance mechanisms by which this antibody blocks HIV-1 entry into a CD4-positive cell.

scholarly journals Discovery and Characterization of a Novel CD4-Binding Adnectin with Potent Anti-HIV Activity

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
David Wensel ◽  
Yongnian Sun ◽  
Zhufang Li ◽  
Sharon Zhang ◽  
Caryn Picarillo ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Viral Entry ◽  
High Affinity ◽  
Glycosylation Sites ◽  
Spectrum Activity ◽  
Anti Hiv ◽  
Hiv 1 ◽  
Broad Spectrum Activity

ABSTRACT A novel fibronectin-based protein (Adnectin) HIV-1 inhibitor was generated using in vitro selection. This inhibitor binds to human CD4 with a high affinity (3.9 nM) and inhibits viral entry at a step after CD4 engagement and preceding membrane fusion. The progenitor sequence of this novel inhibitor was selected from a library of trillions of Adnectin variants using mRNA display and then further optimized for improved antiviral and physical properties. The final optimized inhibitor exhibited full potency against a panel of 124 envelope (gp160) proteins spanning 11 subtypes, indicating broad-spectrum activity. Resistance profiling studies showed that this inhibitor required 30 passages (151 days) in culture to acquire sufficient resistance to result in viral titer breakthrough. Resistance mapped to the loss of multiple potential N-linked glycosylation sites in gp120, suggesting that inhibition is due to steric hindrance of CD4-binding-induced conformational changes.

Anti HIV-1 Agents 7. Discovery of 1-Hydroxy-4-chloro-9,10-anthraquinone Derivatives as New HIV-1 Inhibitors in Vitro

2011 ◽  
Vol 8 (7) ◽  
pp. 602-605
Author(s):  
Ning Huang ◽  
Qin Wang ◽  
Liu-Meng Yang ◽  
Hui Xu ◽  
Yong-Tang Zheng
Keyword(s):  
Anthraquinone Derivatives ◽  
Anti Hiv ◽  
Hiv 1

scholarly journals Organic Nanocarriers for Bevacizumab Delivery: An Overview of Development, Characterization and Applications

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4127
Author(s):  
Aline de Cristo Soares Alves ◽  
Franciele Aline Bruinsmann ◽  
Silvia Stanisçuaski Guterres ◽  
Adriana Raffin Pohlmann
Keyword(s):  
Monoclonal Antibody ◽  
Physicochemical Characterization ◽  
Vascular Endothelial ◽  
Organic Nanoparticles ◽  
Humanized Monoclonal Antibody ◽  
Angiogenesis Process ◽  
Endothelial Growth Factor ◽  
Drug Pharmacokinetics

Bevacizumab (BCZ) is a recombinant humanized monoclonal antibody against the vascular endothelial growth factor, which is involved in the angiogenesis process. Pathologic angiogenesis is observed in several diseases including ophthalmic disorders and cancer. The multiple administrations of BCZ can cause adverse effects. In this way, the development of controlled release systems for BCZ delivery can promote the modification of drug pharmacokinetics and, consequently, decrease the dose, toxicity, and cost due to improved efficacy. This review highlights BCZ formulated in organic nanoparticles providing an overview of the physicochemical characterization and in vitro and in vivo biological evaluations. Moreover, the main advantages and limitations of the different approaches are discussed. Despite difficulties in working with antibodies, those nanocarriers provided advantages in BCZ protection against degradation guaranteeing bioactivity maintenance.

Generation and characterization of a human monoclonal antibody that neutralizes diverse HIV-1 isolates in vitro

AIDS ◽  
1992 ◽  
Vol 6 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Douglas F. Lake ◽  
Takashi Kawamura ◽  
Takami Tomiyama ◽  
W. Edward Robinson ◽  
Yoh-ichi Matsumoto ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Human Monoclonal Antibody ◽  
Hiv 1

scholarly journals Potent Synergistic Anti-Human Immunodeficiency Virus (HIV) Effects Using Combinations of the CCR5 Inhibitor Aplaviroc with Other Anti-HIV Drugs

2008 ◽  
Vol 52 (6) ◽  
pp. 2111-2119 ◽  
Author(s):  
Hirotomo Nakata ◽  
Seth M. Steinberg ◽  
Yasuhiro Koh ◽  
Kenji Maeda ◽  
Yoshikazu Takaoka ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Synergistic Effects ◽  
Immunodeficiency Virus ◽  
Approved Drugs ◽  
Hiv Drugs ◽  
Nonparametric Statistical ◽  
Anti Hiv ◽  
Ccr5 Inhibitor ◽  
Hiv 1

ABSTRACT Aplaviroc (AVC), an experimental CCR5 inhibitor, potently blocks in vitro the infection of R5-tropic human immunodeficiency virus type 1 (R5-HIV-1) at subnanomolar 50% inhibitory concentrations. Although maraviroc is presently clinically available, further studies are required to determine the role of CCR5 inhibitors in combinations with other drugs. Here we determined anti-HIV-1 activity using combinations of AVC with various anti-HIV-1 agents, including four U.S. Food and Drug Administration-approved drugs, two CCR5 inhibitors (TAK779 and SCH-C) and two CXCR4 inhibitors (AMD3100 and TE14011). Combination effects were defined as synergistic or antagonistic when the activity of drug A combined with B was statistically greater or less, respectively, than the additive effects of drugs A and A combined and drugs B and B combined by using the Combo method, described in this paper, which provides (i) a flexible choice of interaction models and (ii) the use of nonparametric statistical methods. Synergistic effects against R5-HIV-1Ba-L and a 50:50 mixture of R5-HIV-1Ba-L and X4-HIV-1ERS104pre (HIV-1Ba-L/104pre) were seen when AVC was combined with zidovudine, nevirapine, indinavir, or enfuvirtide. Mild synergism and additivity were observed when AVC was combined with TAK779 and SCH-C, respectively. We also observed more potent synergism against HIV-1Ba-L/104pre when AVC was combined with AMD3100 or TE14011. The data demonstrate a tendency toward greater synergism with AVC plus either of the two CXCR4 inhibitors compared to the synergism obtained with combinations of AVC and other drugs, suggesting that the development of effective CXCR4 inhibitors may be important for increasing the efficacies of CCR5 inhibitors.

scholarly journals Synthesis and in vitro anti-HIV-1 evaluation of some N-arylsulfonyl-3-formylindoles

2018 ◽  
Vol 54 (3) ◽  
Author(s):  
Zhiping Che ◽  
Yuee Tian ◽  
Shengming Liu ◽  
Mei Hu ◽  
Genqiang Chen
Keyword(s):  
Anti Hiv ◽  
Hiv 1

scholarly journals Mechanism of Action and In Vitro Activity of 1′,3′-Dioxolanylpurine Nucleoside Analogues against Sensitive and Drug-Resistant Human Immunodeficiency Virus Type 1 Variants

1999 ◽  
Vol 43 (10) ◽  
pp. 2376-2382 ◽  
Author(s):  
Zhengxian Gu ◽  
Mark A. Wainberg ◽  
Nghe Nguyen-Ba ◽  
Lucille L’Heureux ◽  
Jean-Marc de Muys ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Mononuclear Cells ◽  
Nucleoside Analogues ◽  
Drug Resistant ◽  
Immunodeficiency Virus ◽  
Blood Mononuclear Cells ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACT (−)-β-d-1′,3′-Dioxolane guanosine (DXG) and 2,6-diaminopurine (DAPD) dioxolanyl nucleoside analogues have been reported to be potent inhibitors of human immunodeficiency virus type 1 (HIV-1). We have recently conducted experiments to more fully characterize their in vitro anti-HIV-1 profiles. Antiviral assays performed in cell culture systems determined that DXG had 50% effective concentrations of 0.046 and 0.085 μM when evaluated against HIV-1IIIB in cord blood mononuclear cells and MT-2 cells, respectively. These values indicate that DXG is approximately equipotent to 2′,3′-dideoxy-3′-thiacytidine (3TC) but 5- to 10-fold less potent than 3′-azido-2′,3′-dideoxythymidine (AZT) in the two cell systems tested. At the same time, DAPD was approximately 5- to 20-fold less active than DXG in the anti-HIV-1 assays. When recombinant or clinical variants of HIV-1 were used to assess the efficacy of the purine nucleoside analogues against drug-resistant HIV-1, it was observed that AZT-resistant virus remained sensitive to DXG and DAPD. Virus harboring a mutation(s) which conferred decreased sensitivity to 3TC, 2′,3′-dideoxyinosine, and 2′,3′-dideoxycytidine, such as a 65R, 74V, or 184V mutation in the viral reverse transcriptase (RT), exhibited a two- to fivefold-decreased susceptibility to DXG or DAPD. When nonnucleoside RT inhibitor-resistant and protease inhibitor-resistant viruses were tested, no change in virus sensitivity to DXG or DAPD was observed. In vitro drug combination assays indicated that DXG had synergistic antiviral effects when used in combination with AZT, 3TC, or nevirapine. In cellular toxicity analyses, DXG and DAPD had 50% cytotoxic concentrations of greater than 500 μM when tested in peripheral blood mononuclear cells and a variety of human tumor and normal cell lines. The triphosphate form of DXG competed with the natural nucleotide substrates and acted as a chain terminator of the nascent DNA. These data suggest that DXG triphosphate may be the active intracellular metabolite, consistent with the mechanism by which other nucleoside analogues inhibit HIV-1 replication. Our results suggest that the use of DXG and DAPD as therapeutic agents for HIV-1 infection should be explored.

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