An In Vivo Technique to Track Bispecific Antibody-Induced T Cell Trafficking to Tumors

Take an anesthetized, immunocompromised mouse bearing a subcutaneous tumor xenograft that overexpresses a tumor-associated antigen or TAA.

Retroorbitally inject effector T cells expressing the luciferase enzyme.

Subcutaneously administer interleukin 2, a cytokine supporting effector T cell survival.

Retroorbitally inject bispecific antibodies engineered to contain binding sites for T and tumor cells. Allow the mouse to recover.

The antibodies and T cells reach the tumor via circulation.

The antibodies bind to CD3 on the T cells and TAA on the tumor cells, inducing the effector T cells to release toxins that initiate apoptosis in the tumor cells and release chemokines that recruit more T cells to the tumor.

Anesthetize the mouse, retroorbitally inject a luciferase substrate, and proceed to in vivo imaging.

Luciferase inside the T cells oxidizes the substrate, emitting bioluminescence.

Observe the bioluminescence over time. The magnitude of the signal correlates with the extent of T cell infiltration within the tumor.