Modulation of B cell maturation and migration to the thymus of SJL mice. B cell migration to the thymus.
The direct linkage of the B cell maturation process and infiltration of the thymus with mature B cells was studied in SJL mice. Phenotypically and functionally, B cells in the thymus of old SJL mice are mature B cells; IgM+, IgD+, Ly-1-, and evince a high proliferative response to lipopolysaccharide and a low one to dextran sulphate. Memory B cells can be found in the thymus of mice immunized with T-dependent or T-independent antigens. Chronic depletion and B cell maturation arrest induced by fractionated total lymphoid irradiation or by neonatal splenectomy eliminate B cells from the thymus and block their migration from the periphery to the thymus. When examined in adoptive transfer experiments, thymus B cells were found to possess a normal migration pattern and homing receptors; their migration pattern did not differ from that of lymph node or splenic B cells. It is evident, therefore, that the large number of normal functioning B cells in the thymus of SJL mice reflects a massive infiltration of the thymus by mature B cells from the periphery due to thymus dysfunction rather than to an abnormal in situ differentiation of intrathymic B cell precursors.
Hart
M
M
Pediatric Department, Kaplan Hospital, Rehovot, Israel.
Zan-Bar
I
I
D000818:Animals; D000831:Animals, Newborn; D001402:B-Lymphocytes / Q000166:cytology* / Q000502:physiology / Q000528:radiation effects; D002454:Cell Differentiation; D002465:Cell Movement; D005260:Female; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains; D016201:Receptors, Lymphocyte Homing / Q000378:metabolism; D013156:Splenectomy; D013950:Thymus Gland / Q000166:cytology*
D016201:Receptors, Lymphocyte Homing