Variant antibodies that bind ox40

A method for inducing proliferation of effector T cells, comprising:

• contacting the effector T cells with a fully human antibody of an IgG class that binds OX40, or an antigen binding portion thereof, wherein the fully human antibody comprises a heavy chain variable domain sequence that is at least 95% identical to the amino acid sequences of SEQ ID NO. 9, and a light chain variable domain sequence selected from the group consisting of SEQ ID NO. 3 (called 5-A6 herein), SEQ ID NO. 4 (called 5-A8 herein), SEQ ID NO. 5 (called 5-C8) herein), SEQ ID NO. 6 called 5-F5 herein SEQ ID NO. 7 (called 5-G8 herein), and SEQ ID NO. 8 (called 5-H6 herein).

A method for inducing effector T cells to increase production of at least one cytokine, comprising:

• contacting effector T cells with a fully human antibody of an IgG class that binds OX40, or an antigen binding portion thereof, wherein the fully human antibody comprises a heavy chain variable domain sequence that is at least 95% identical to the amino acid sequences of SEQ ID NO. 9, and a light chain variable domain sequence selected from the group consisting of SEQ ID NO. 3 (called 5-A6 herein), SEQ ID NO. 4 (called 5-A8 herein), SEQ ID NO. 5 (called 5-C8) herein), SEQ ID NO. 6 called 5-F5 herein SEQ ID NO. 7 (called 5-G8 herein), and SEQ ID NO. 8 (called 5-H6 herein).

A method for inducing proliferation of effector T cells (Teff) in the presence of regulatory T cells (Treg), comprising:

• contacting the effector T cells and the regulatory T cells with a fully human antibody of an IgG class that binds OX40, or an antigen binding portion thereof, wherein the fully human antibody comprises a heavy chain variable domain sequence that is at least 95% identical to the amino acid sequences of SEQ ID NO. 9, and a light chain variable domain sequence selected from the group consisting of SEQ ID NO. 3 (called 5-A6 herein), SEQ ID NO. 4 (called 5-A8 herein), SEQ ID NO. 5 (called 5-C8) herein), SEQ ID NO. 6 called 5-F5 herein SEQ ID NO. 7 (called 5-G8 herein), and SEQ ID NO. 8 (called 5-H6 herein).