RESUMO
Mast cells originate from pluripotent hematopoietic stem cells. Two mast cell specific antibodies, mAbsAA4 and BGD6, have previously been used to identify and study committed mast cell precursors (MCcps) in the bone marrow of adult mice and rats. However, the embryonic origin of MCcps is still not known. In the present study, we identified MCcps in rat embryos using these previously characterized mast cell specific antibodies. The MCcps were found in the AGM (aorta-gonad-mesonephros) region of rat embryos at E11.5. These cells were BGD6+, CD34(+), c-kit(+), CD13(+), FcεRI(-), AA4(-) CD40(-), and Thy-1(-). By PCR the cells contained message for the α and ß subunits of FcεRI and mast cell specific proteases. In vitro, the MCcps differentiated into metachromatic mast cells. With age of gestation the percent of MCcps diminished while the percent of mast cell progenitors increased. An increased knowledge of the biology and embryonic origin of mast cells may contribute to a greater understanding of allergy, asthma, and other mast cell related diseases.
Assuntos
Aorta/embriologia , Gônadas/embriologia , Células-Tronco Hematopoéticas/citologia , Mastócitos/citologia , Mesonefro/embriologia , Animais , Aorta/metabolismo , Diferenciação Celular , Feminino , Gônadas/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Separação Imunomagnética , Fígado/embriologia , Fígado/metabolismo , Masculino , Mastócitos/metabolismo , Glicoproteínas de Membrana/metabolismo , Mesonefro/metabolismo , Ratos , Receptores de Complemento/metabolismo , Receptores de IgE/genética , Receptores de IgE/metabolismoRESUMO
Uterine natural killer (uNK) cells are the dominant lymphocytes found in pregnant mammals that develop uterine decidualization. Four stages of mouse uNK cell differentiation are recognized using Dolichos biflorus agglutinin (DBA) lectin histochemistry. Each uNK cell subtype has a preferential domain. In human and mouse normal pregnancies, uNK cells are activated interferon gamma-producing cells that promote angiogenesis and development of the decidua and placenta. Murine transplant models suggest that uNK cells differentiate from self-renewing progenitors found in peripheral secondary lymphoid tissues, particularly spleen and lymph nodes. In this work, the spleen was removed 7 days before mice were mated to address whether absence of the spleen reduced uNK cell numbers or altered the distributions of maturing uNK cell subsets using quantitative lectin histochemistry. Splenectomy delayed uNK cell maturation within implantation sites. This coincided with delayed decidual and placental development and a significant (48 hr) lengthening of gestation without loss of viability. These studies characterize spleen as a biologically important progenitor tissue for uNK precursor cells.