Skip to main content
. 2015 Mar 24;10(3):e0120648. doi: 10.1371/journal.pone.0120648

Fig 4. Correlation of gp120/CD4 blocking antibodies and CD4bs antibodies with the neutralizing capacity of plasma samples.

Fig 4

A) Gp120/CD4 blocking activity showed no correlation with the titer of CD4bs antibodies (Spearman´s correlation). Dotted line indicated the positivity cut-off of each parameter. Three groups of plasma samples were defined using cut-off values: plasma samples showing CD4bs and gp120/CD4 blocking antibodies (+/+), samples with detectable gp120/CD4 blocking Abs but undetectable CD4bs Abs (-/+) and plasma samples lacking both specificities (-/-).B) Titer of BG505 SOSIP.664 reactive antibodies showed a weak positive correlation with CD4bs Abs. Dotted line indicated the positivity cut-off of each parameter. Note that most of plasma samples negative for CD4bs Abs showed Env-reactive antibodies. C) gp120/CD4 blocking activity was plotted against the titer of BG505 SOSIP.664 binding antibodies and titer of CD4bs antibodies. Six plasma samples showing high reactivity against the trimer and variable levels of CD4bs antibodies and gp120/CD4 blocking activity are outlined (clear symbols). D) Neutralizing capacity of plasma samples were assayed using four viral isolates: NL4.3, BaL, AC10 and SVPB16. Samples were classified according to panel A. Dotted lines indicate upper and lower dilutions of plasma samples assayed. E) Samples lacking CD4bs Abs but showing gp120/CD4 blocking Abs (-/+) and F) samples showing both specificities (+/+) were analysed for correlation between gp120/CD4 blocking activity and neutralizing capacity (reciprocal IC50) using the viral isolates described in D. Spearman´s correlation analysis was performed (r and p values are only shown for significant correlations).