Disclosed herein are methods of using anti-ILT5 antibodies and ILT5-binding fragments thereof to induce an immunostimulatory effect in a T cell when such a T cell is contacted with an antigen presenting cell (APC) that has been previously contacted with the anti-ILT5 antibody or ILT5-binding fragment. Also disclosed herein are methods of using anti-ILT5 antibodies and ILT5-binding fragments thereof to inhibit a response in a T cell (e.g., a proliferative response) when such a T cell is concomitantly contacted, or has previously been contacted, with an APC, which APC is simultaneously contacted with the anti-ILT5 antibody or ILT5-binding fragment. Also disclosed herein are methods of using anti-ILT5 antibodies and ILT5-binding fragments thereof for the treatment of various diseases and for use as immunostimulatory adjuvants.
