Extended Data Fig. 3: T-ALL patient cells arrested at the β-selection checkpoint express barely detectable levels of a functional pre-TCR.
From: Pre-TCR-targeted immunotherapy for T cell acute lymphoblastic leukemia
(A) Flow cytometry of CD3 vs TCRαβ expression of T-ALL patient samples representative of developmental arrest at the β-selection checkpoint (T-ALL42, T-ALL43), recovered from spleen xenografts of NSG mice from two independent experiments (left biparametric histograms). Monoparemetric histograms on the right show pre-TCR surface expression on electronically gated CD3lo TCRneg cells analysed with anti-pTα monoclonal antibody plus biotin-coupled anti-mouse (Fab’)2 plus PE-coupled streptavidin. Shaded histograms represent background staining with an irrelevant isotype-matched control. (B) Immunoblot analysis of ERK and S6 phosphorylation in pre-TCR+ T-ALLs (T-ALL42, T-ALL43) stimulated either with anti-pTα or with anti-CD3ε monoclonal antibodies for the indicated times from a single experiment. One experiment per T-ALL sample was performed. Total ERK and S6 expression is shown as loading control.
