In situ studies of the primary immune response to (4-hydroxy-3-nitrophenyl)acetyl. III. The kinetics of V region mutation and selection in germinal center B cells.
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In the murine spleen, germinal centers are the anatomic sites for antigen-driven hypermutation and selection of immunoglobulin (Ig) genes. To detail the kinetics of Ig mutation and selection, 178 VDJ sequences from 16 antigen-induced germinal centers were analyzed. Although germinal centers appeared by day 4, mutation was not observed in germinal center B cells until day 8 postimmunization; thereafter, point mutations favoring asymmetrical transversions accumulated until day 14. During this period, strong phenotypic selection on the mutant B lymphocytes was inferred from progressively biased distributions of mutations within the Ig variable region, the loss of crippling mutations, decreased relative clonal diversity, and increasingly restricted use of canonical gene segments. The period of most intense selection on germinal center B cell populations preceded significant levels of mutation and may represent a physiologically determined restriction on B cells permitted to enter the memory pathway. Noncanonical Ig genes recovered from germinal centers were mostly unmutated although they probably came from antigen-reactive cells. Together, these observations demonstrate that the germinal center microenvironment is rich and temporally complex but may not be constitutive for somatic hypermutation.
Immunoglobulin Heavy Chains
Immunoglobulin Variable Region
Mice, Inbred C57BL
Molecular Sequence Data
Polymerase Chain Reaction
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James B. Duke Distinguished Professor of Immunology
1. Lymphocyte development and antigen-driven diversification of immunoglobulin and T cell antigen receptor genes. 2. The germinal center reaction and mechanisms for clonal selection and self - tolerance. The origins of autoimmunity. 3. Interaction of innate- and adaptive immunity and the role of inflammation in lymphoid organogenesis. 4. The role of secondary V(D)J gene rearrangment in lymphocyte development and malignancies. 5. Mathematical modeling of immune responses,