General Topics: D.H. Adams, S. Shaw, and G. van Seventer, Lymphocyte Adhesion Molecules: Role in Cell Adhesion and Intercellular Communication. E.C. Snow, Signaling Mechanisms Utilized by Mammalian Cells. J.D. Ashwell, Lymphocyte Programmed Cell Death. D. Zharhary, Age Related Decline in B and T Cell Immunity. T Lymphocytes: K.L. McCoy, Mechanisms Responsible for the Processing and Presentation of Antigens to T Cells. K.B. Urdahl andM.K. Jenkins, Antigen Presenting Cell Regulation of T Cell Activation. C.R. Mackay, The Concept of Memory T Cells. W. Born, K.A. Kelly, and R. OBrien, g/l T Cells. D.J. Cohen and P.A. Henkart, Cytolytic T Cell Development and Function. S.H.E. Kaufmann and M.J. Reddehase, T Cell Subsets and Defense against Bacteria and Viruses. V. Kumar, V. Bhardwaj, and E. Sercarz, T Cell Recognition of Defined Peptides and Autoimmunity. B Lymphocytes: L.B. Justement, The B Cell Antigen Receptor: Consideration of Structure and Function. M.L. Peterson, RNA Processing and Expression of Immunoglobulin Genes. S. Bondada and M. Garg, Thymus–Independent Antigens. L.S. Marshall and R.J. Noelle, Distinctive Signaling Pathways for TI versus TD Responses. W. Cushley and M.M. Harnett, Regulation of B Lymphocyte Cell Growth and Differentiation by Soluble Mediators. D.L. Morris and T.L. Rothstein, CD5+ B (B–1) Cells and Immunity. R. Krumdieck andJ.E. Volanakis, Complement as an Effector Mechanism of Antibodies in Host Defense. D.M. Klinman, Natural Antibodies, Immune Networks, and Autoimmunity.