Cell Granularity Reflects Immune Cell Function and Enables Selection of Lymphocytes with Superior Attributes for Immunotherapy

In keeping with the rule of “form follows function”, morphological aspects of a cell can reflect its role. Here, it is shown that the cellular granularity of a lymphocyte, represented by its intrinsic side scatter (SSC), is a potent indicator of its cell state and function. The granularity of a lymphocyte increases from naïve to terminal effector state. High‐throughput cell‐sorting yields a SSC(high) population that can mediate immediate effector functions, and a highly prolific SSC(low) population that can give rise to the replenishment of the memory pool. CAR‐T cells derived from the younger SSC(low) population possess desirable attributes for immunotherapy, manifested by increased naïve‐like cells and stem cell memory (T(SCM))‐like cells together with a balanced CD4/CD8 ratio, as well as enhanced target‐killing in vitro and in vivo. Altogether, lymphocyte segregation based on biophysical properties is an effective approach for label‐free selection of cells that share collective functions and can have important applications for cell‐based immunotherapies.