Cellular basis of B cell clonal populations in old mice.
Previous studies from this laboratory have shown that >85% of old mice have stable B cell clonal populations detectable by Ig heavy chain complementary-determining region 3 mRNA size analysis and confirmed by sequence analysis. B cells from the same clone are frequently detected in several lymphoid compartments of the same mouse. We now report the phenotype of all ten stable B cell clonal populations detected in five 20-month-old C57BL/6 mice. These clonal B cells appear to develop in the periphery and nine of the ten B cell clonal populations expressed the CD5 cell surface marker. Stable B cell expansions may be dominated by cells at two stages of differentiation. Some B cell populations were detected with DNA as well as RNA and represent large clonal populations of B cells, detectable in several lymphoid compartments. These populations are found predominantly in B cell populations expressing CD45R/B220 and the mRNA coding for the membrane-bound form of the mu Ig heavy chain, which suggests a predominance of B lymphocytes in these populations. In other cases, smaller clonal populations were detected only in splenic RNA samples. These clonal populations were found predominantly among CD45R/B220- B cells and did not express the membrane-bound form of the micro Ig heavy chain. We offer the hypothesis that the B cell clonal populations present in old mice may be precursors of the two types of B cell neoplasms which are dominated by CD5+ B cells (B cell chronic lymphocytic leukemia) or plasma cells (multiple myeloma).
LeMaoult
J
J
Division of Geriatrics and Gerontology, Weill Medical College of Cornell University, New York 10021, USA.
Manavalan
J S
JS
Dyall
R
R
Szabo
P
P
Nikolic-Zugic
J
J
Weksler
M E
ME
D000375:Aging / Q000276:immunology*; D000818:Animals; D016175:B-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology; D019070:Cell Lineage / Q000276:immunology; D016922:Cellular Senescence / Q000276:immunology; D002999:Clone Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D005260:Female; D007148:Immunoglobulin mu-Chains / Q000235:genetics; D017493:Leukocyte Common Antigens / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D009928:Organ Specificity / Q000276:immunology; D010529:Peritoneal Cavity / Q000166:cytology; D012333:RNA, Messenger / Q000096:biosynthesis; D011947:Receptors, Antigen, B-Cell / Q000235:genetics; D013234:Stem Cells / Q000166:cytology / Q000276:immunology
D007148:Immunoglobulin mu-Chains; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell; D017493:Leukocyte Common Antigens