Unusual phenotype of B cells in the thymus of normal mice.
A small number of B cells are found in the thymus of normal mice. A population of B lymphocytes could be enriched to greater than 90% purity by isolating a low-density fraction on Percoll density gradients and then depleting T cells with a mixture of anti-Thy-1, CD4, and CD8 mAbs and complement. Enrichment was monitored by surface Ig staining and by functional studies (responsiveness to LPS, and to anti-mu plus IL-4). When the phenotype of these B cells was studied by flow cytometry, 60-80% had the phenotype Ly-1+ (CD5), Ia+, B220low (CD45R), and Mac-1+ (CD 11b). In contrast, splenic B cells lacked CD5 and CD11b and expressed higher levels of B220 and Ia antigens. These results indicate that most thymic B cells have the phenotype of the Ly-1 B cell subset, which was identified previously as a trace subpopulation in some peripheral tissues and is thought to play a role in autoantibody formation.
Miyama-Inaba
M
M
First Department of Pathology, Kansai Medical University, Moriguchi, Japan.
Kuma
S
S
Inaba
K
K
Ogata
H
H
Iwai
H
H
Yasumizu
R
R
Muramatsu
S
S
Steinman
R M
RM
Ikehara
S
S
D000818:Animals; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000145:classification / Q000276:immunology*; D002478:Cells, Cultured; D005260:Female; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D009928:Organ Specificity; D012016:Reference Values; D013154:Spleen / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology*
D000911:Antibodies, Monoclonal