Infectivity of HIV-1
mutants containing the N674D mutation or a combination of gp41 glycan deletions. In addition to the single glycan-deleting N → Q mutations in gp41, we also generated one N → D mutation and several combinations of N → Q mutations. The infectivity of these virus strains was studied using C8166 cells, which were infected at day 0. Subsequently, samples were harvested during 7 consecutive days. The number of eGFP positive cells was quantified using flow cytometry. The infection curves were used for linear regression analysis, to quantifiy the infectivity of the virus strains. Data are the means ± SEM of 2–3 independent experiments. The difference between WT and mutant virus was considered to be significant when the p value calculated using the student’s t-test was <0.05 (* = p < 0.05, ** = p < 0.005).