Non-invasive fluorescence imaging for tracking immune cells in preclinical models of immunotherapy

The field of cellular immunotherapy for cancer has experienced exponential growth over the last decade. Several chimeric antigen receptor T cell products have already received FDA approval, which has stimulated growth and enthusiasm for other cellular therapies. Preclinical models are critical steps in the development of these products, and understanding their in vivo trafficking and persistence are critical components of their efficacy and toxicity analogous to volume of distribution and tissue penetration in small molecule therapeutics. Thus, well-established preclinical methodologies for following cells after adoptive transfer are important to understanding immune cell trafficking to, and persistence in, tumors or organs of interest. Here, we describe a quick and reliable method for labeling and in vivo tracking of immune cells adoptively transferred into small animal models by using in vivo fluorescent imaging.