Comparison of hypothetical antibody responses against single versus multi-immunogen vaccine regimens. Two vaccine regimens are compared: (A) single immunogen (e.g. gp120) and (B) multiple immunogens (e.g. eOD-GT6, gp120 and SOSIP gp140). The portion of the protein that corresponds to eOD-GT6 is shown in green. Amino acid residues identical among all three immuogens are indicated in yellow, and those that contact VRC01 are identified in red. The extent of hypothetical B cell expansion and antibody diversification is illustrated by different sizes of the cone and phylogenetic trees. Epitopes targeted by undesirable antibodies (strain-specific or non-neutralizing) are exemplified as epitopes E2 or E4. An immunorecessive epitope (e.g. CD4BS) targeted by VRC01-class antibodies is exemplified as E1 epitope.