Although immunologists know rather a lot about the manif estation of immunological memory, an understanding of the mechanism of memory at cellular and biochemical levels eludes us. Indeed, as we shall see, it is not even clear which of the several models used to explain the working of memory approximates to the truth. It is in order to report on approaches to this problem and on recent experimental advances in the field of memory cells that this volume has been put together. In the past 4-5 years cell surface molecules that may enable us to define memory Band T cells have been identified. It may now be possible to ask how memory cells are generated and to define what signals are required during or after antigenic encounter for a cell to enter the memory cell pool rather than to terminally differentiate into an effector cell. The transition from virgin cell to memory cell is clearly accompanied by several biochemical changes. For B cells, isotype switching and somatic mutations (leading to affinity maturation) are well-defined phenomena, although the molecular mechanisms remain mys terious. Both have received attention in many excellent reviews of late and so are not considered in detail in this book. Neither switching nor somatic mutation is a feature of peripheral T-cell maturation; biochemical differences between virgin and mem ory T cells may only relate to differing activation requirements and possibly changes in the expression of accessory molecules.
List of Contents.- Expansion, Selection and Maintenance of Memory B-Cell Clones.- The Generation of B-Cell Memory: A Working Hypothesis.- The Evolution of B-Cell Clones.- Antiviral T-Cell Memory?.- Subsets of Rat CD4+ T Cells Defined by Their Differential Expression of Variants of the CD45 Antigen: Developmental Relationships and In Vitro and In Vivo Functions.- Pgp-1 (Ly 24) As a Marker of Murine Memory T Lymphocytes.- Human T-Cell Memory.- Suppressor T-Cell Memory.