Efficiency of HIV-1 content release at neutral pH.

<p>HXB2pp labeled with releasable content marker Gag-imCherry and extra-viral pH sensor EcpH-ICAM were pre-bound in the cold to cells and imaged at 37°C for 60 min. (A) Graph shows the content release efficiency measured in LCIB, LCIB supplemented with 100 nM BafA1 or HBSS with CV1/CD4/CXCR4 cells, as well as with CV-1 cells lacking CD4 (CV1/CD4-) bathed in LCIB. In control experiments, fusion was carried out in the presence of 10 μM AMD3100. Total number of particles examined for each condition listed on top of plot. Statistical analyses performed using two tests (nonparametric Mann-Whitney test and zero-inflated Poisson model) did not reveal significant differences between either of the conditions tested. (B) Snapshot of HXB2pp (white circle) before and after content release in interaction with CV1/CD4/CXCR4 cell during treatment with 10 μM AMD3100 and corresponding fluorescent intensity profile of particle. (C) Illustration of loss of mCherry through defects in the viral membrane.