Minor Antigen Disparities Impede Induction of Long Lasting Chimerism and Tolerance through Bone Marrow Transplantation with Costimulation Blockade

Figure 1

mHAg disparities impede rates of chimerism achieved through BMT with CB. (a) depicts the BMT protocol used with distinct donor-recipient combinations. (b) FACS plots show total donor (34-2-12 mAb recognizes H-Dd) and recipient type cells in CD4, CD8, B cells, and myeloid cells of one representative recipient of Balb/c BMC at the end of observation period. Dead cells were excluded through propidium iodide (PI) staining. (c) Rates of chimeras were determined at different time points after BMT. Early multilineage chimerism was induced in almost all mice. Maintenance of chimerism was observed in all but one recipient mouse of MHC mismatched, but mHAg matched B10.D2 () bone marrow throughout the observation period. In contrast, chimerism rates dropped in mice, which were transplanted with BMC of MHC and mHAg mismatched Balb/c () mice over time similarly to mice, which received MHC mismatched but mHAg matched B10.A () BMC ( for both versus B10.D2 BMC recipients after week 16). (d) Chimerism levels among CD4 cells, CD8 cells, B cells, and myeloid cells were measured by FCM at different time points after BMT. All groups of recipients showed relatively similar chimerism levels among T cell lineages throughout the observation period. Significantly higher chimerism was observed in B cells among recipients of MHC mismatched, but mHAg matched B10.D2 () bone marrow compared to mice transplanted with MHC and mHAg mismatched Balb/c () BMC ( at all measured time points). Myeloid cell chimerism was significantly lower in recipients of MHC mismatched, but mHAg matched B10.A () after week 6 after BMT compared to recipients of Balb/c () BMC ( and at indicated time points). Mean percent of chimerism, interquartile range (box), and SD (whiskers) of long-term chimeras are shown as box-and-whisker blots (representative data from 1 of 2 independent experiments). (e) Chimerism levels of long-term chimeras after transplantation of Balb/c BMC, B10.D2 BMC, or B10.A BMC, respectively, at the end of observation period. Individual percent, mean percent of chimerism, and SD (error bars) are shown as scatter plot (pooled data of two independent experiments).

(a)

(b)

(c)

(d)

(e)