Detection of P815 leukemic cells in the peripheral blood of mice.

P815 mastocytoma cells were identified by flow cytometry by the expression of recipient type (H-2^d), but not donor type, (H-2^b) MHC class I molecules. P815 cells were identified on 3 of 3 mice having clinical leukemic signs after BM grafting plus TK T cell infusion and GCV treatment from day 1 to day 3, as illustrated here.