For fresh lymphoid cells (PBMC, lymph nodes, splenocytes), we typically stain 1-2x106 cells. For clones and CTL lines, you can probably get away with as few as 2x105 cells. When staining clones, it ...

(H&E stain, original magnification x 400). Abdominal lymph node with nodular collections of histocyte-like cells occurring in sarcoid-like pattern. (H&E stain, original magnification x 100).