Scheme 1.

Synthesis of the conjugates. (A) Synthesis of (OVA)S^−/+(CpG) or S^−/+(OVA−CpG) conjugates. p−MWNT was oxidized using acidic mixture yielding MWNT 1. The carboxylic acid moieties of MWNT 1 were reacted with Boc−protected amine−terminated spacer via amide coupling reaction yielding S^−/+. (OVA)S^−/+(CpG) was synthesized by the simultaneous addition of OVA and CpG to S^−/+, while S^−/+(OVA−CpG) was synthesized by reacting the OVA−CpG with S^−/+. (B) Synthesis of (αCD40)S^−/+(OVA−CpG). αCD40 was first conjugated with S^−/+ yielding (αCD40)S^−/+ that following conjugation with OVA−CpG yielded (αCD40)S^−/+(OVA−CpG).