Effect of e1a2Mz transduction on normal human CD34⁺ CBCs. (A) Transgenic expression of hCD2 in CD34⁺ CBCs was determined by FCM 3 days after gene transduction. Cells were also stained with anti-CD34 antibody. Representative data from 3 samples are shown. ^*The numbers in the plots indicate the percentage of cells in that quandrant. (B) Death of CD34⁺ CBCs transduced with the indicated vectors, or untransduced, was determined by the trypan blue exclusion test up to 14 days after transduction. The results represent means of data from 3 CD34⁺ CBC samples. (C) Colony formation analysis of CD34⁺ CBCs transduced with the indicated vectors or untransduced. Number and types of colonies formed in semisolid media were assessed 14 days after transduction. The results represent means ± SDs of data from 3 CD34⁺ CBC samples. CFU-GM indicates granulocyte-macrophage colony-forming unit; BFU-E, erythroid burst-forming unit; and CFUGEMM, granulocyte-erythrocyte-megakaryocyte-macrophage colony-forming unit.