623 Immuno-STATs: Leveraging protein engineering to expand and track antigen-specific T cells in vivo by Ronald Seidel, Mohammad Rashidian, Stad Zeigler, Andrew Woodham, Mengyan Li, Ella Zeyang, Stephen Kolifrath, Kaitlyn O’Connor, Rodolfo Chaparro, Maia Mesyngier, Ross Cheloha, Jason Dearling, Phaneendra Duddempudi, Alev Celikgil, Scott Garforth, Alan Packard, Harris Goldstein, Hidde Ploegh, Steven Almo