PRE-B-CELLS IN RAT BONE-MARROW - IDENTIFICATION, SURFACE-MARKERS AND ISOLATION

In adult rats, as in other species, bone marrow has the highest potential for B-lymphocyte genesis as determined by a long-term repopulation assay for B-lymphocyte stem cells (1). These cells carry the Thy-1 and W3/13 antigens (2, 3). Pre-B cells characterized by the presence of µ heavy chains in the cytoplasm (cµ) but not on the cell surface (sµ) have been described in mice (4), men (5) and rabbits (6) but not in rats, and appear to be the immediate precursors of B-lymphocytes (7–10). The relation between pre-B cells and B-lymphocyte stem cells is not clear, however. Therefore, the aims of the present study were to identify cµ+sµ- pre-B cells in rat bone marrow and to find surface markers that would permit isolation of viable pre-B cells to subsequently assay their functional potential in vivo

Somatic mutation of immunoglobulin VH6 genes in human infants

Infants respond to antigen by making antibody that is generally of low affinity for antigen. Somatic hypermutation of immunoglobulin genes, and selection of cells expressing mutations with improved affinity for antigen, are the molecular and cellular processes underlying the maturation of antibody affinity. We have reported previously that neonates and infants up to 2 months of age, including individuals undergoing strong immunological challenge, show very few mutated VH6 sequences, with low mutation frequencies in mutated sequences, and little evidence of selection. We have now examined immunoglobulin genes from healthy infants between 2 and 10 months old for mutation and evidence of selection. In this age group, the proportion of VH6 sequences which are mutated and the mutation frequency in mutated sequences increase with age. There is evidence of selection from 6 months old. These results indicate that the process of affinity maturation, which depends on cognate T–B cell interaction and functional germinal centres, is approaching maturity from 6 months old

Relationship Between An Enhancer Element In The Human Antithrombin-iii Gene And An Immunoglobulin Light-chain Gene Enhancer

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62691/1/316845a0.pd