Long-term haematopoietic reconstitution and survival without interleukin-7 in a murine syngeneic bone marrow transplantation model

Abstract

We created a syngeneic mouse bone marrow transplantation (BMT) model to examine the effect of endogenous interleukin-7 (IL-7) on long-term (≥140 days) haematopoietic reconstitution and survival after BMT. Wild-type (WT) IL-7+/+ and knockout (KO) IL-7-/- mice were lethally irradiated and transplanted with bone marrow. Survival is best (85.7%) in the group WT grafts transplanted into WT recipients (WT→WT) with a trend towards poorer survival in the other groups (WT→KO: 60%, KO→WT: 50%, KO→KO: 45.5%, differences statistically not significant). If the recipient is deficient for IL-7-producing cells, T- and B-cell reconstitution remain incomplete. If the graft lacks IL-7-producing cells there is a significant delay in T- and NK-cell reconstitution. Interestingly, in the absence of IL-7, T-cell reconstitution is neither delayed nor incomplete because of an expansion of TCRαβ+/CD4-/CD8- double negative T cells. Long-term survival and lymphocyte reconstitution after syngeneic BMT can occur despite the absence of IL-7. © 2006 The Authors.