Fig. 1.

Primary and secondary engraftment failure in MHC-matched MCM post-allogeneic HSCT. a, b Longitudinal white blood cell (WBC), T cell, and platelet absolute counts in recipient macaques 32851 (a), 32846 (b), and 32849 (b). Immune conditioning regimens are indicated in top panels (Bu = busulfan, Flu = fludarabine, TBI = total body irradiation, CD3-IT = CD3-immunotoxin). CD8 depleting mAb was administered only to 32849, indicated by an asterisk (*). Colored circumflexes (^) indicate time points at which donor-derived cells were detected in whole blood by chimerism assays. Crosses (†) indicate time of necropsy. Normal WBC reference range = 5,600–184,000/μl; normal platelet reference range = 134,000–564,000/μl. Shaded gray boxes in a–c indicate tacrolimus treatment period. Vertical dotted line in b indicates second transplant of 32846. c Longitudinal donor chimerism levels in 32846 and 32849 as measured by Illumina sequencing whole blood genomic DNA across SNPs differing between donor and recipient. Graphs display mean ± SEM frequencies of donor-derived cells as measured by sequencing two (32849) or three (32846) SNPs. d Mixed lymphocyte reactions assessing levels of CD4+ and CD8+ T cell alloreactivity in recipient macaque 32846 pre-HSCT and 28 days post-HSCT. Plots display proliferation of CFSE-labeled recipient T cells in response to irradiated donor cells, as measured by frequency of CFSE-lo cells. Plots are gated on live, CD3+ singlets, and either CD4+ or CD8+ cells. Recipient cells cultured alone (no stim) or with Staphylococcus enterotoxin B (SEB) served as negative and positive controls, respectively.