Relaxed negative selection in germinal centers and impaired affinity maturation in bcl-xL transgenic mice.
Takahashi Y, Cerasoli DM, Dal Porto JM, Shimoda M, Freund R, Fang W, Telander DG, Malvey EN, Mueller DL, Behrens TW, et al. J Exp Med. 1999 Aug 2; 190(3):399-410.