Cutting edge: β-catenin is dispensable for T cell effector differentiation, memory formation, and recall responses.

The molecular mechanisms that regulate mature T cell fate and enable cells to differentiate into memory T cells are largely unknown. Memory T cells share certain key features with stem cells: they both have the ability to self-renew and are long-lived. The Wnt-β-catenin signaling pathway is a key player in regulating stem cell self-renewal and differentiation. We generated a conditional knockout mouse that specifically lacks β-catenin in mature T cells and report in this article that β-catenin is not involved in regulating effector versus memory T cell differentiation. β-catenin-deficient memory T cells were phenotypically and functionally indistinguishable from control cells and made normal recall responses. β-catenin deficiency does not affect T cell migration, T cell function in a model of chronic infection, or lymphopenia-induced proliferation. Together, our data suggest that self-renewal and differentiation are regulated differently in memory T cells compared with epithelial and hematopoietic stem cells.