An Anti-Programmed Death‑1 Antibody (αPD-1) Fusion Protein That Self-Assembles into a Multivalent and Functional αPD‑1 Nanoparticle Peng Zhao Djordje Atanackovic Shuyun Dong Hideo Yagita Xiao He Mingnan Chen 10.1021/acs.molpharmaceut.6b01021.s001 https://acs.figshare.com/articles/journal_contribution/An_Anti-Programmed_Death_1_Antibody_PD-1_Fusion_Protein_That_Self-Assembles_into_a_Multivalent_and_Functional_PD_1_Nanoparticle/4888781 Cancer immune checkpoint therapy has achieved remarkable clinical successes in various cancers. However, current immune checkpoint inhibitors block the checkpoint of not only the immune cells that are important to cancer therapy but also the immune cells that are irrelevant to the therapy. Such an indiscriminate blockade limits the efficacy and causes the autoimmune toxicity of the therapy. It might be beneficial to use a carrier to target immune checkpoint inhibitors to cancer-reactive immune cells. Here, we explore a method to load the inhibitors into carriers. We used the anti-programmed death-1 antibody (αPD-1) as a model immune checkpoint inhibitor. First, we generated a recombinant single-chain variable fragment (scFv) of αPD-1. Then, we designed and generated a fusion protein consisting of the scFv and an amphiphilic immune-tolerant elastin-like polypeptide (iTEP). Because of the amphiphilic iTEP, the fusion was able to self-assemble into a nanoparticle (NP). The NP was proved to block the PD-1 immune checkpoint <i>in vitro</i> and <i>in vivo</i>. Particularly, the NP exacerbated diabetes development in nonobese diabetic mice as effectively as natural, intact αPD-1. In summary, we successfully expressed αPD-1 as a recombinant protein and linked αPD-1 to a NP, which lays a foundation to develop a delivery system to target αPD-1 to a subpopulation of immune cells. 2017-03-25 00:00:00 target α PD α PD -1. NP α PD therapy amphiphilic immune-tolerant elastin-like polypeptide checkpoint inhibitors block