37 research outputs found

    C3 region sequences of the sequential viruses.

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    <p>The sequences shown represent the consensus sequence from 3–11 clones. The sequences were derived from the same aliquot of virus culture supernatant that was used in the neutralization assay.</p

    Neutralization curves of anti-V3 monoclonal antibodies against sequential viruses.

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    <p>Neutralization sensitivity of HIV-1 subtype B and CRF02_AG viruses obtained sequentially from patient ITM60 (a and b), NYU104 (c and d), 3506 (e and f), ITM27 (g and h), and ITM39 (i and j) with anti-V3 monoclonal antibodies. The dash horizontal line represents 50% neutralization.</p

    Neutralization curves of anti-V2, anti-CD4bd, and anti-carbohydrate monoclonal antibodies against sequential viruses.

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    <p>Neutralization sensitivity of HIV-1 subtype B and CRF02_AG viruses obtained from patient ITM60 (a and b), NYU104 (c and d), 3506 (e and f), ITM27 (g and h), and ITM39 (i and j) with anti-V2, anti-CD4bd, and anti-carbohydrate monoclonal antibodies. The dash horizontal line represents 50% neutralization.</p

    V2 region sequences of the sequential viruses.

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    <p>The sequences shown represent the consensus sequence from 3–11 clones. The sequences were derived from the same aliquot of virus culture supernatant that was used in the neutralization assay.</p

    V3 loop sequences of the sequential viruses.

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    <p>The sequences shown represent the consensus sequence from 3-11 clones. The sequences were derived from the same aliquot of virus culture supernatant that was used in the neutralization assay. The core epitope to which the anti-HIV-1 monoclonal antibodies were directed is boxed. The epitope specificity of the monoclonal antibodies (mAb) was mapped using HIV-1 MN V3 peptides and the core epitope sequences of the MN peptide are shown along with the monoclonal antibody.</p

    Thermodynamic Signatures of the Antigen Binding Site of mAb 447–52D Targeting the Third Variable Region of HIV‑1 gp120

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    The third variable region (V3) of HIV-1 gp120 plays a key role in viral entry into host cells; thus, it is a potential target for vaccine design. Human monoclonal antibody (mAb) 447–52D is one of the most broadly and potently neutralizing anti-V3 mAbs. We further characterized the 447–52D epitope by determining a high-resolution crystal structure of the Fab fragment in complex with a cyclic V3 and interrogated the antigen–antibody interaction by a combination of site-specific mutagenesis, isothermal titration calorimetry (ITC) and neutralization assays. We found that 447–52D’s neutralization capability is correlated with its binding affinity and at 25 °C the Gibbs free binding energy is composed of a large enthalpic component and a small favorable entropic component. The large enthalpic contribution is due to (i) an extensive hydrogen bond network, (ii) a π–cation sandwiching the V3 crown apex residue Arg<sup>315</sup>, and (iii) a salt bridge between the 447–52D heavy chain residue Asp<sup>H95</sup> and Arg<sup>315</sup>. Arg<sup>315</sup> is often harbored by clade B viruses; thus, our data explained why 447–52D preferentially neutralizes clade B viruses. Interrogation of the thermodynamic signatures of residues at the antigen binding interface gives key insights into their contributions in the antigen–antibody interaction

    The IC<sub>50</sub> values of anti-V3 mAbs against 57 HIV-1 pseudoviruses tested using the U87 target cell line.

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    <p>The IC<sub>50</sub> values were estimated from the titration curves of all mAb/psV combinations and are highlighted according to the color-coded scale. Pseudoviruses expressing Envs of JRCSF, NL3.4, and SF162 were tested as positive controls, whereas the irrelevant anti-parvovirus mAb 860 and aMLV Env-expressing psV were used as negative controls. When 50% neutralization was not achieved at the highest mAb concentration tested (50 µg/ml), the IC<sub>50</sub> values are shown as >50.</p

    The neutralization of nine HIV-1 pseudoviruses by mAb 2191 using U87 as target cells.

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    <p>The neutralization curves of anti-V3 mAb 2191 against nine selected HIV-1 pseudoviruses are shown with their corresponding AUC and IC<sub>50</sub> values. Fifty percent neutralization is denoted by the dashed line. Significant neutralization at the confidence level of p<0.001 (denoted with * after AUC values) was determined statistically based on comparison with the AUC values of the negative controls together with the slopes of the titration curves as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0010254#s2" target="_blank">Materials and Methods</a>. For viruses coming from patients where the date of infection is known, viruses are denoted as coming from acutely- or chronically-infected patients, and the clade of the virus is denoted by the capital letter in its name (A, B, C or D).</p
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