The present invention provides antibodies that bind to the T-cell co-inhibitor programmed death-1 (PD-1) protein, and methods of use. In various embodiments of the invention, the antibodies are fully human antibodies that bind to PD-1. In certain embodiments, the present invention provides multi-specific antigen-binding molecules comprising a first binding specificity that binds to PD-1 and a second binding specificity that binds to an autoimmune tissue antigen, another T-cell co-inhibitor, an Fc receptor, or a T-cell receptor. In some embodiments, the antibodies of the invention are useful for inhibiting or neutralizing PD-1 activity, thus providing a means of treating a disease or disorder such as cancer or a chronic viral infection. In other embodiments, the antibodies are useful for enhancing or stimulating PD-1 activity, thus providing a means of treating, for example, an autoimmune disease or disorder.本發明提供結合至T細胞共抑制劑程序性死亡-1(PD-1)蛋白的抗體，及使用方法。在本發明的不同具體例中，該等抗體是結合至PD-1的完全人類抗體。在某些具體例中，本發明提供多特異性抗原結合分子，其包含結合至PD-1的第一結合特異性以及結合至自體免疫組織抗原(另一種T細胞共抑制劑、Fc受體或T細胞受體)的第二結合特異性。在一些具體例中，本發明抗體可用於抑制或中和PD-1活性，因而提供治療諸如癌症或慢性病毒感染之疾病或病症的工具。在其他具體例中，該等抗體可用於增強或刺激PD-1活性，因而提供治療例如自體免疫疾病或病症的工具。
