NKT-cell activation by B cells is dependent on the LDL-R. (A) CD40L-activated B cells were cultured overnight with NKT cells, 200 ng/mL αGalCer, and apoE together with blocking antibodies or corresponding isotype control antibodies as indicated. (B) CD40L-activated B cells were cultured with NKT cells with αGalCer alone (media) or αGalCer with rApoE2, rApoE3, or rApoE4. (C) CD40L-activated B cells were cultured with NKT cells with αGalCer in SFM (media), αGalCer plus apoE, 5% human serum (HS), or PHA. (A-C) NKT cell activity (mean ± SEM of IFN-γ secretion from triplicate wells) for 1 representative experiment is shown (performed on 3 individual tonsils).