F. Matsuda and T. Honjo, Organization of the Human Immunoglobulin Heavy-Chain Locus.J. Chen, Analysis of Gene Function in Lymphocytes by RAG-2-Deficient Blastocyst Complementation.A. Billiau, Interferon-gamma: Biology and Role in Pathogenesis.K.S. Hathcock and R.J. Hodes, Role of the CD28-B7 Costimulatory Pathways in T Cell-Dependent B Cell Responses.W.L. Smith and D.L. DeWitt, Prostaglandin Endoperoxide H Synthases-1 and -2.R.A. Hendersonand O.J. Finn, Human Tumor Antigens Are Ready to Fly.N.W. Lukacs and P.A. Ward, Inflammatory Mediators, Cytokines, and Adhesion Molecules in Pulmonary Inflammation and Injury.Chapter References.Subject Index.Contents of Recent Volumes.