Autocrine expression of interleukin-7 rescues lymphoid expansion in interleukin-7-deficient mice.
The murine interleukin-7 (IL-7) gene was disrupted to examine the role of IL-7 in the lymphoid system. Expansion of lymphoid cells is sharply curtailed in IL-7-deficient mice. This is evident in a dramatic reduction but not elimination of lymphoid cells in the thymus, bone marrow and spleen. The few thymocytes present express CD4 and/or CD8 markers associated with T-cell maturation. Similarly, a limited number of B cells detected in the bone marrow rearrange and express immunoglobulin genes. Small but distinct populations of B and T cells are found in the spleens of IL-7-deficient mice. Thus the signal transmitted by IL-7 plays a central role in the expansion of lymphocytes while it is not absolutely required for their maturation. A transgene that directs expression of IL-7 to lymphoid cells was found to restore the numbers of thymocytes, bone marrow B-cell progenitors and splenic lymphocytes of IL-7-deficient mice to approximately normal levels. This genetic complementation confirms that the lymphoid defect is specifically due to the absence of IL-7 and demonstrates that the expansion of lymphoid cells in an organism is regulated by their exposure to IL-7.
Rich
B E
BE
Department of Genetics, Harvard Medical School, Boston, MA, USA.
D000818:Animals; D019898:Autocrine Communication / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D015139:Blotting, Southern; D001853:Bone Marrow / Q000276:immunology; D015851:Interleukin-7 / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D007958:Leukocyte Count; D008221:Lymphoid Tissue / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D009929:Organ Size; D013154:Spleen / Q000276:immunology / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology / Q000473:pathology
D015851:Interleukin-7