Contents. List of Contributors. Preface (J.FAP. Miller). Long-Term Human Hematopoiesis In Vitro Using Cloned Stromal Cell Lines and Highly Purified Progenitor Cells (F.M. Cicuttini, M. Martin, D. Maher, and A.W. Boyd). Multiple Routes for Late Intrathymic Precursors to Generate CD4+CD8+ Thymocytes (P. Hugo and H.T. Petrie). Immunity Versus Tolerance: The Cell Biology of Positive and Negative Signaling of B. Lymphocytes (G.J.V. Nosan). Self-Tolerance in the T Cell Repertoire (J.F.A.P. Miller and G. Morahan). Coordinate and Differential Regulation of GM-CSF and IL-3 Synthesis in Murine T Lymphocytes (A.B. Troutt, N. Tsoudis, and A. Kelso). Host-Parasite Interactions in Leishmaniasis (E. Handman). The Nonobese Diabetic (NOD) Mouse: A Model for the Study of the Cell Biology of the Pathogenesis of an Organ-Specific Autoimmune Disease (T.E. Mandel). Epigenetic Regulation of the Early Development of the Nervous System (P.F. Bartlett and M. Murphy). Index.