Objective: To evaluate the effect of sensitized sera on engraftment of hematopoietic stem cells (HSCs) and its mechanism.
Methods: Bone marrow cells (BMCs) from C57BL/6 mice were incubated with sensitized sera (group I) or normal sera (group II), and then washed and transplanted into irradiated BALB/c mice. The survival analysis and engraftment evaluation of the recipients were observed. The incubated BMCs were bound with goat anti mouse IgG for and labeled with Annexin V for apoptosis detection.
Results: Seven out of ten recipient mice in group I died of bone marrow failure at day 10 after transplantation, while all of those in group II were long-term survived. Engraftment assay showed recipients blood count and BMCs progressively decreased along with time passing in group I; in addition, the chimeric percentage of donor cells progressively decreased as well. The percentage of BMCs binding with goat anti mouse IgG in group I or group II were (90.3 +/- 5.1)% and (5.2 +/- 2.4)%, respectively, and the difference was statistically significant (P < 0.01). However, no significant difference was found in the apoptosis detection between the two groups (P > 0.05).
Conclusion: The engraftment capacity of HSCs is significantly impaired by sensitized sera, the antibodies in sensitized sera may bind to antigens expressed on HSCs but do not induce apoptosis.