Figure 1.

Schematic representation of the interaction between CD4 and gp120, with reference to the formation of new epitopes. The indicated monoclonal antibodies are either exclusively (CG10) or preferentially (DB-81) binding to CD4 complexed to gp120 (right part of the figure), as compared to CD4 only (left part of the figure). Similarly, the anti-gp120 D19 monoclonal antibody is represented, which binds with higher affinity to gp120 complexed to CD4, as compared to (R5-coreceptor restricted) gp120 only. The affinities of the antigen-antibody interactions are proportional to the thickness of the arrow pointing to the epitope.