Interaction between HMRCs and CD34⁺, CD15⁺, or GlyA⁺ cells. (A) Bone slides were stained with either anti-CD34, anti-CD15, or anti-glycophorin A antibody followed by Alexa-fluor 594 goat anti-mouse immunoglobulin secondary antibody, and examined under fluorescent microscope. (Ai) CD34⁺ cells are in physical contact with the cell body and cytoplasmic extensions of a HMRC. CD15⁺ (Aii) or GlyA⁺ cells (Aiii) are not found close to HMRCs. HMRCs and immunophenotyped cells are indicated by arrows and arrowheads, respectively. (Aiv) One HMRC in the hematopoietic parenchyma interacts with 7 CD34⁺ cells (numbered arrowheads). Numerical letters at the left corner of each panel indicate the position of z-axis in the analytical planes. All bars represent 10 μm. (B) Quantification of the interaction between HMRCs and CD34⁺, CD15⁺, or GlyA⁺ cells. (Bi) Frequencies of HMRCs interacting with CD34⁺, CD15⁺, or GlyA⁺ cells. (Bii) The vast majority of HMRCs located in the endosteal region interact with CD34⁺ cells. (Biii) Frequencies of CD34⁺, CD15⁺, or GlyA⁺ cells interacting with HMRCs. (Biv) In the endosteal region, 2-fold more CD34⁺ cells interact with HMRCs than in the central marrow. Each white circle represents a value obtained by counting. ^*P < .005 relative to the CD15 and GlyA groups; ^**P < .005 and ^***P < .05 relative to the central group.