LCK-deficient CD8 T-cell show reduced proliferation but normal effector responses in vivo

The overall study investigated the role of LCK and FYN in peripheral CD8⁺ T-cell responses using adoptive transfers of LCK- or FYN-deficient monoclonal T cells into polyclonal hosts. To assess the role of LCK in T-cell differentiation in greater detail, we performed a single-cell transcriptomics study of WT, LCK CA (knock-in mice with LCK unable to bind to CD4/CD8 co-receptors), and LCK KO OT-I CD8⁺ T cells responding to LM-OVA on day 5 post-infection. While the WT and LCK CA T cells were indistinguishable, LCK KO T cells exhibited a higher frequency of effector T cells and a lower frequency of memory T cells compared to the controls. The study presents three experimental conditions: CD8⁺ T cells extracted from either WT, KO, or CA monoclonal OT-I mice. Each condition includes two or three biological replicates.