Methods and compositions for activation of T cells using nanoparticles conjugated with multiple ligands for binding receptors on T cells

A particle, which can be a microparticle or nanoparticle, comprising two different targeting agents,

• wherein each of the targeting agents is conjugated directly to the particle's surface,
• wherein the two different targeting agents are not conjugated to each other,
• wherein each of the targeting agents binds to a different protein receptor on a T cell surface, and
• wherein the two different targeting agents are an antagonistic PD-1 antibody or active fragment thereof, and an agonistic OX40 antibody or active fragment thereof, respectively.