Figure 1. Reducing TcR signal strength and antigen affinity increases memory precursor effector cell development during a primary immune response.

Experimental scheme detailing the adoptive transfer method described in materials and methods is shown in (A), along with flow cytometric analysis of sort purified naïve WT and Itk^−/− OT-1/Rag^−/− CD8⁺ T cells. (B, D) Number of WT and Itk^−/− cells over time following infection with LM-N4 and LM-T4. Note log scale. (C, E) Percentages of CD127^loKLRG1^hi (SLECs) and CD127^hiKLRG1^lo (MPECs) was determined from blood samples collected weekly for a month in mice that received WT or Itk^−/− cells. (F, G) Overlaid data to underscore differences in cell number, and SLEC and MPEC percentages under changes in TcR signal strength and antigen affinity. (H) On D30 T_CM (CD44^hiCD62L^hi), T_EM (CD44^hiCD62L^lo) and LLEC (CD27^loKLRG1^hi) memory cell subsets were quantified (percent, top panels; number, bottom panels). *p<0.05 and n.s. = “Not Significant” based upon one-way and two-way ANOVA. Data (mean ± SEM) is representative of three independent experiments with n ≥ 3–4. n=4 in WT and Itk^−/− group receiving LM-N4; n=3 for WT group receiving LM-T4; n=4 for Itk^−/− group receiving LM-T4.