The Mcl-1 transgene causes splenic enlargement and enhances spleen cell survival in vitro. (A) Shown are spleens from two 12-week-old male littermates, one transgenic for Mcl-1 (left) and one nontransgenic (right). (B) Spleens from transgenic and nontransgenic mice were explanted, and the splenocytes were placed in suspension in standard medium, incubated in tissue culture, and assayed daily for cell viability by trypan blue dye exclusion. The points shown are the mean ± SE for cells from 18 transgenic mice and 12 matched nontransgenic controls. The significance of the difference between nontransgenic and transgenic cells, as assessed by analysis of variance with the Scheffé test, indicated a P value of <.01 for days 1, 2, 3, and 4.