5lqb
Complex structure of human IL2 mutant, Proleukin, with Fab fragment of NARA1 antibody
Structural highlights
DiseaseIL2_HUMAN Note=A chromosomal aberration involving IL2 is found in a form of T-cell acute lymphoblastic leukemia (T-ALL). Translocation t(4;16)(q26;p13) with involves TNFRSF17. FunctionIL2_HUMAN Produced by T-cells in response to antigenic or mitogenic stimulation, this protein is required for T-cell proliferation and other activities crucial to regulation of the immune response. Can stimulate B-cells, monocytes, lymphokine-activated killer cells, natural killer cells, and glioma cells. Publication Abstract from PubMedInterleukin-2 (IL-2) immunotherapy is an attractive approach in treating advanced cancer. However, by binding to its IL-2 receptor alpha (CD25) subunit, IL-2 exerts unwanted effects, including stimulation of immunosuppressive regulatory T cells (Tregs) and contribution to vascular leak syndrome. We used a rational approach to develop a monoclonal antibody to human IL-2, termed NARA1, which acts as a high-affinity CD25 mimic, thereby minimizing association of IL-2 with CD25. The structure of the IL-2-NARA1 complex revealed that NARA1 occupies the CD25 epitope of IL-2 and precisely overlaps with CD25. Association of NARA1 with IL-2 occurs with 10-fold higher affinity compared to CD25 and forms IL-2/NARA1 complexes, which, in vivo, preferentially stimulate CD8+ T cells while disfavoring CD25+ Tregs and improving the benefit-to-adverse effect ratio of IL-2. In two transplantable and one spontaneous metastatic melanoma model, IL-2/NARA1 complex immunotherapy resulted in efficient expansion of tumor-specific and polyclonal CD8+ T cells. These CD8+ T cells showed robust interferon-gamma production and expressed low levels of exhaustion markers programmed cell death protein-1, lymphocyte activation gene-3, and T cell immunoglobulin and mucin domain-3. These effects resulted in potent anticancer immune responses and prolonged survival in the tumor models. Collectively, our data demonstrate that NARA1 acts as a CD25-mimobody that confers selectivity and increased potency to IL-2 and warrant further assessment of NARA1 as a therapeutic. Improved cancer immunotherapy by a CD25-mimobody conferring selectivity to human interleukin-2.,Arenas-Ramirez N, Zou C, Popp S, Zingg D, Brannetti B, Wirth E, Calzascia T, Kovarik J, Sommer L, Zenke G, Woytschak J, Regnier CH, Katopodis A, Boyman O Sci Transl Med. 2016 Nov 30;8(367):367ra166. PMID:27903862[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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