Presence of B cell progenitors in the thymus.
We characterize B cell progenitors in the thymus. Although mature thymic B cells are surface Ig+, B220(high), but CD43-, B cell progenitors in the thymus were found to be slg-, B220(med), and CD43+. Most progenitors showed rearranged Ig D-J and V-D-J patterns when DNA from sorted B cell progenitors was amplified by PCR, blotted, and probed. When B cell progenitors were purified from the thymus and injected intrathymically into Ig heavy chain (Igh) allotype-disparate recipients, B cells bearing donor-type Igh6 were detected in the thymus but not in the periphery. Thymic B cells generated from these progenitors were CD5+ cells, although there was a broad range of expression of CD5 molecules. Furthermore, B cells purified from thymus that had been inoculated with B cell progenitors were able to differentiate into Ab-forming cells under the influence of CD40 ligand plus IL-10, and secreted IgM with donor Igh6 allotype. We thus clarified the existence of B cell progenitors in the thymus and also characterized the surface markers and their developmental functions.
Mori
S
S
First Department of Pathology, Kansai Medical University, Moriguchi, Osaka, Japan.
Inaba
M
M
Sugihara
A
A
Taketani
S
S
Doi
H
H
Fukuba
Y
Y
Yamamoto
Y
Y
Adachi
Y
Y
Inaba
K
K
Fukuhara
S
S
Ikehara
S
S
D000818:Animals; D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D023201:CD40 Ligand; D002454:Cell Differentiation; D005260:Female; D005434:Flow Cytometry; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D005803:Genes, Immunoglobulin; D017493:Leukocyte Common Antigens / Q000032:analysis*; D051917:Leukosialin; D008562:Membrane Glycoproteins / Q000494:pharmacology; D051379:Mice; D008809:Mice, Inbred C3H; D011947:Receptors, Antigen, B-Cell / Q000032:analysis*; D012795:Sialoglycoproteins / Q000032:analysis*; D013950:Thymus Gland / Q000166:cytology*
D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D051917:Leukosialin; D008562:Membrane Glycoproteins; D011947:Receptors, Antigen, B-Cell; D012795:Sialoglycoproteins; C497863:Spn protein, mouse; D023201:CD40 Ligand; D017493:Leukocyte Common Antigens