Anxa2 regulates homing of bone marrow progenitor cells to bone marrow. Survival was evaluated following intravascular injection of 2 × 105 bone marrow cells into irradiated mice. Control mice received a sham injection. (A) Radiated mice received intravenous injections of anti-Anxa2 antibody, p11 (the binding partner of Anxa2), or an isotype-matched antibody control at 0, 2, and 24 hours after transplantation. (B) Recipient mice were inoculated with either N-terminal Anxa2 peptide or a scrambled peptide (control) at the time of the transplantation as well as 2 hours and 24 hours later. Survival was analyzed using the Kaplan-Meier method. Data are representative data of 3 experiments. *P < .05 versus the control. Histologic examination of the bone marrow (C) and spleens (D) of experimental animals taken at day 9. (i) Representative data of normal histology of animals receiving no treatment. (ii) Animals received an N-terminal Anxa2 peptide only. (iii) Animals were treated with an anti-Anxa2 antibody only. (iv) Animals were treated with lethal irradiation (2 doses of 570 cGy). (v) Animals were treated with irradiation and a marrow transplantation (2 × 105 cells). (vi) Animals were treated with irradiation, a marrow transplantation, and an N-terminal Anxa2 peptide. (vii) Animals were treated with irradiation, a marrow transplantation, and an anti-Anxa2 antibody. (viii) Animals were treated with irradiation, a marrow transplantation, and a scrambled peptide. (ix) Animals were treated with irradiation, a marrow transplantation, and an IgG control antibody. Regeneration of hematopoietic marrow was noted in animal marrows, and spleen was noted in animals receiving transplants and control antibody and scrambled peptide (arrows) at 20 ×. Bars indicate 100 microns. Image acquisition information is in caption to Figure 2.
