Infection in vitro, this protein was tested for clinical efficacy in HIV-1-infected individuals; however, no effect on plasma viral loads was observed [13]. Further examination revealed that doses of sCD4 that were significantly higher than those achieved in the clinical trial were required to neutralize primary clinical isolates of HIV-1, in contrast to the relatively sensitive, laboratory-adapte
Washing buffer (140 mM NaCl, 1.8 mM CaCl2, 1 mM MgCl2 and 20 mM Tris, pH 7.5). A horseradish peroxidase-conjugated antibody specific for the Fc region of human IgG was then incubated with the samples for 45 minutes at room temperature. Cells were washed 5 times with blocking buffer and 5 times with washing buffer. HRP enzyme activity was determined after the addition of 33 ml per well of a 1:1 mix
NM (4 mg/ml) and 12 nM (0.6 mg/ml), respectively (Figure 1A). In CD42CCR5+ cells, sCD4 activated infection of HIV-1(AD8) much more efficiently than that of HIV-1(YU2). A similar pattern of HIV-1 activation and inactivation was observed for the NBD-556 analogue, JRC-II-191, herein referred to as 191. The affinity of 191 for the HIV-1YU2 gp120 envelope glycoprotein (Kd = 760 nM) is significantly low
Ce of sCD4 (40 mg/ml, 0.8 mM) and then adsorbed by diffusion or magnetically to cultures of the indicated cell type. Measured luciferase activity is presented as mean relative light units (RLU)6standard error of the mean (s.e.m.) of three replicate samples. doi:10.1371/journal.ppat.1000360.gPLoS Pathogens | www.plospathogens.orgMetastable Activation of HIV-1 Envto enhance HIV-1 infection of CD42CC
To current convention [46]). C34-Ig was produced and purified as previously described [47]. The CD4-Ig fusion protein consists of the first two N-terminal domains of the CD4 molecule and the Fc region of human IgG1. Purification was carried out as described for the C34-Ig molecule [47].mechanism of sCD4 neutralization [17,18]. Resistance to sCD4 may thus arise by a decreased affinity of the envelo
To current convention [46]). C34-Ig was produced and purified as previously described [47]. The CD4-Ig fusion protein consists of the first two N-terminal domains of the CD4 molecule and the Fc region of human IgG1. Purification was carried out as described for the C34-Ig molecule [47].mechanism of sCD4 neutralization [17,18]. Resistance to sCD4 may thus arise by a decreased affinity of the envelo