Reactivity of patient plasma with recombinant human DBY and DBX proteins. (A) Recombinant p24, DBY, and DBX proteins produced in E coli were probed in Western blots with antibodies specific for the V5 epitope tag and plasma obtained from 2 male patients after allogeneic HSCT. The location of the full-length recombinant DBY protein is indicated by the arrow. (B) Recombinant DBY and DBX were expressed in human female 293 cells, and total cell lysates were probed in Western blots with antibodies specific for the V5 epitope tag and plasma obtained from the same male patients shown in panel A. Results with DBY and DBX are compared with 293 cells transfected with an empty vector (mock transfectants). The location of the full-length recombinant DBY protein is indicated by the arrow.