Limited density of an antigen presented by RMA-S cells requires B7-1/CD28 signaling to enhance T-cell immunity at the effector phase. oleh Xiao-Lin Li, Marjolein Sluijter, Elien M Doorduijn, Shubha P Kale, Harris McFerrin, Yong-Yu Liu, Yan Li, Madhusoodanan Mottamal, Xin Yao, Fengkun Du, Baihan Gu, Kim Hoang, Yen H Nguyen, Nichelle Taylor, Chelsea R Stephens, Thorbald van Hall, Qian-Jin Zhang