The effect of Rauscher leukaemia virus on haemopoietic cell differentiation in genetically defective W/Wv and normal mice

textabstractThe main objective of the studies presented in this thesis is to clarify the controversial issue concerning the primary role of the stem cell in Rauscher erythroblastosis. Genetically anemic mice carrying the W mutation, characterized by a stem cell differentiation defect, have been chosen as an experimental model for these investigations. In Chapter 3, the susceptibility of W/Wv genotypes to Rauscher infection is examined by several known parameters, such as spleen weight, peripheral blood values, etc. The relationship between the development of Rauscher disease in these mutants and a restoration of their stem cell differentiation defect, is evaluated by the spleen colony assay. Chapter 4 deals with studies of the functional properties of RLVinfected W/Wv stem cells, assayed in lethally irradiated W/Wv recipients. The 30-day radioprotective capacity of RLV-infected W/Wv CFU-S, the numerical and physical properties of erythrocytes generated by these cells, as well as the capacity of RLV-infected W/Wv stem cells to give rise to tissue mast cells in W/Wv recipients, are investigated. Chapter 5 describes the development and establishment of serum free cultures for the stimulation of stem cells and progenitor cells with specific regulators in vitro. The elimination of serum, known to contain specific haemopoietic regulators, is a prerequisite for accurate investigations into the role of regulatory mechanisms in the expression of haemopoietic disorders. In an attempt to elucidate the mechanism(s) by which RLV infection exerts its effects on the haemopoietic system, with special relevance to the early stages of haemopoietic cell differentiation, the effect of RLV infection on the sensitivity of stem cells and progenitor cells to specific regulators in vitro, is examined in both normal and genetically anemic W/Wv mice. These investigations are described in Chapter 6. Chapter 7 describes studies performed in lethally irradiated recipients, in which the effect of the W mutation and RLV infection on stem cell differentiation and self renewal in both the spleen and femur, are investigated. In the final chapter, the information obtained in these studies is incorporated into a model relating the primary involvement of the haemopoietic stem cell in the development of Rauscher erythroblastosis