A B220(-), CD19(-) population of B cells in the peripheral blood of quasimonoclonal mice.
We describe a new population of non-naive B cells in the peripheral blood of quasimonoclonal (QM) mice. Surface Ig of switched isotypes is expressed, but not B220 nor CD19. These cells are larger and denser than naive B cells but smaller than blasts or plasma cells; they do not stain with syndecan, a marker for plasma cells. Telomerase, which is usually expressed in B cell blasts, was not present in this population. We sorted the switched, idiotype-positive, B220(-) B cells from the peripheral blood of QM mice and sequenced Ig H chain and lambda L chain cDNA. There were many point mutations but no V gene replacements, gene conversions or other type of diversifications. As they express switched isotypes and have mutated their Ig genes, cells in the B220(-), CD19(-) population must have been in an immune response and we suggest that it includes the memory B cell subset.
Cascalho
M
M
Department of Microbiology, University of California, San Francisco, CA 94143-0670, USA.
Wong
J
J
Brown
J
J
Jäck
H M
HM
Steinberg
C
C
Wabl
M
M
D000595:Amino Acid Sequence; D000818:Animals; D018941:Antigens, CD19 / Q000032:analysis*; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D001483:Base Sequence; D005803:Genes, Immunoglobulin; D005818:Genetic Engineering; D006412:Hematopoietic Stem Cells; D017578:Immunoglobulin Class Switching / Q000235:genetics*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007130:Immunoglobulin Idiotypes; D007142:Immunoglobulin gamma-Chains / Q000235:genetics; D017493:Leukocyte Common Antigens / Q000032:analysis*; D008562:Membrane Glycoproteins; D051379:Mice; D008817:Mice, Mutant Strains; D008969:Molecular Sequence Data; D010537:Peritoneum / Q000166:cytology; D011509:Proteoglycans; D011947:Receptors, Antigen, B-Cell; D053667:Syndecans; D019098:Telomerase
D018941:Antigens, CD19; D007143:Immunoglobulin Heavy Chains; D007130:Immunoglobulin Idiotypes; D007142:Immunoglobulin gamma-Chains; D008562:Membrane Glycoproteins; D011509:Proteoglycans; D011947:Receptors, Antigen, B-Cell; D053667:Syndecans; D019098:Telomerase; D017493:Leukocyte Common Antigens