Intrinsic TLR2-MyD88 signaling increases cellular proliferation and survival after in vitro stimulation and is dependent on the PI3K pathway. (A,B) Polyclonal CFSE-labeled WT or MyD88^−/− CD8 T cells were stimulated in vitro with plate-bound anti-CD3 antibody alone (αCD3) or anti-CD3 antibody coupled with plate-bound anti-CD28 (αCD3 αCD28), Pam₃Cys (αCD3 Pam₃Cys), Pam₃Cys and the PI3K inhibitor LY294002 (αCD3 Pam₃Cys LY294002), or left unstimulated (naive) as a control. After 18 hours of stimulation, T cells were removed from stimulation and placed back into culture in the absence of further stimulation for a total of 4 days. At this time, both the CFSE profile (A) as well as the survival of CD8⁺ cells by annexin V staining (B) were determined by flow cytometry. Percentage of annexin V⁻ cells among total CD8⁺ T cells is indicated. Representative data from 4 independent experiments are shown.