Imaging antigen-specific T cells

Abstract

Immunology Positron emission tomography (PET) has previously been exploited to trace immune responses in living animals. However, its use has been largely limited to cells expressing surrogate markers recognized by radiolabeled antibodies or cells genetically modified to take up radio-labeled substrates. Woodham et al. now report a nonintrusive, in vivo method to track antigen-specific T cells that recognize known antigens presented by major histocompatibility complex (MHC) molecules. The authors made a class of radiolabeled peptide-bound MHC dimers linked to antibody Fc regions, which they called “synTacs.” In a mouse model of cancer, they were able to follow CD8+ T cells within tumors that recognized a particular oncoprotein. They could also detect influenza virus (IAV) nucleoprotein–specific CD8+ T cells in the lungs of IAV-infected mice. This work may help pave the way for future tools to noninvasively track human T cell responses during interventions such as vaccination and cancer immunotherapy. Nat. Methods 17 , 1025 (2020).