How memory is retained is an immunological mystery. One possibility, argued here by Fons UytdeHaag and colleagues, is that memory is imprinted in the somatically-mutated Ig expressed by certain CD5+ B cells. The theory proposes that the Ig expressed by this self-renewing population acts as surrogate antigen, selecting and stimulating emerging antigen-specific lymphocytes.

*Antigens, CD, *Gene Rearrangement, B-Lymphocyte, *Immunologic Memory, 0 (Antibodies, Anti-Idiotypic), 0 (Antigens, CD), 0 (Antigens, CD5), 0 (Immunoglobulin Variable Region), 0 (Immunoglobulins, Heavy-Chain), 0 (Immunoglobulins, Light-Chain), 0 (Immunoglobulins, Surface), Animals, Antibodies, Anti-Idiotypic/genetics/immunology, Antigens, CD5, B-Lymphocyte Subsets/*immunology, Genes, Immunoglobulin, Hematopoietic Stem Cells/immunology, Human, Immunoglobulin Variable Region/genetics, Immunoglobulins, Heavy-Chain/genetics, Immunoglobulins, Light-Chain/genetics, Immunoglobulins, Surface/genetics/*immunology, Mice, Models, Biological, Mutation, Plasma Cells/immunology, Support, Non-U.S. Gov't,
Immunology Today
Erasmus MC: University Medical Center Rotterdam

UytdeHaag, F, van der Heijden, R.W.J, & Osterhaus, A.D.M.E. (1991). Maintenance of immunological memory: A role for CD5+ B cells?. Immunology Today, 12(12), 439–442. doi:10.1016/0167-5699(91)90016-M