CD45-ADC broadly depletes hematopoietic cells. (A) Total bone marrow (BM) cells, lineage (Lin)-depleted BM cells, or LSK (Lin-Sca1+ cKit+) cells isolated from WT B6 mice were cultured in the media along with different concentrations of unconjugated CD45 Ab, CD45-ADC, or isotype-ADC for 5 days. Viability of cells was analyzed by flow cytometry on d5. (B) CD45-ADC-mediated depletion of hematopoietic progenitor cells (LSKs) and HSCs (ST-HSC: LSKCD150+CD48+ or LT-HSC: LSKCD150+CD48−) in BM was assessed 2 days after IV administration in WT B6 mice (n = 3 per group, 10- to 12-week-old female). The frequencies of progenitors and HSCs were analyzed by flow cytometry, and absolute cell counts/femur were calculated. Nontreated mice served as control. (C) The number of WBCs, neutrophils, lymphocytes, and monocytes in BM were assessed 2 days after IV administration of CD45-ADC or isotype-ADC in WT B6 mice (n = 3 per group). Nontreated mice served as control. Data in (B) and (C) represent mean ± SEM. Experiments were performed twice, and data shown are from 1 representative experiment. *P < .05 vs untreated mice, using ANOVA with posthoc Tukey’s multiple comparisons test.