FACS analysis of splenic populations. (Upper panel) FSC histogram analyzing the cell size. A rectangle defines the normal sized splenocytes. (Lower panel) CD4 and CD8 double fluorescence patterns. (A) Analysis of normal control splenocytes. (B) Analysis of a transgenic mouse with a major tumoral load. Nearly all splenic cells are large sized CD8⁺ prolymphocytes. (C) Analysis of a transgenic mouse with minor tumoral load. FCS histogram shows a larger than normal sized cell population with a CD8⁺ phenotype (not shown). (D) Analysis of a small cell variant. An excess of CD8⁺ cells is clearly visible, but no larger than normal cells are detected on the FSC histogram.