37 research outputs found
C3 region sequences of the sequential viruses.
<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
CD4 profile of HIV-1 infected study subjects.
<p>All the study subjects were asymptomatic. CD4 counts were determined by FACScan.</p
Neutralization curves of anti-V3 monoclonal antibodies against sequential viruses.
<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.
<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.
<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
Anti-HIV-1 monoclonal antibody concentrations (µg/ml) required to yield 50% neutralization with the HIV-1 infected patients' sequential viruses.
<p>Anti-HIV-1 monoclonal antibody concentrations (µg/ml) required to yield 50% neutralization with the HIV-1 infected patients' sequential viruses.</p
V3 loop sequences of the sequential viruses.
<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
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.
<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.
<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