Splenectomy of rats selectively reduces lymphocyte function-associated antigen 1 and intercellular adhesion molecule 1 expression on B-cell subsets in blood and lymph nodes.
Splenectomy increases the number of B cells in the blood of humans and animals. It is unknown whether this is due to changes in migration, proliferation, or both. The numbers of naïve (IgD(+)IgM(+)), memory (IgD(-)IgM(high)), newly formed (IgM(high)CD90(high)), early recirculating follicular (IgM(low)CD90(high)), recirculating follicular (IgM(low)CD90(-)), and marginal zone (IgM(high)CD90(-)) phenotype B cells were determined in control and splenectomized rats by flow cytometry. All subsets increased significantly in the blood after splenectomy. Because surface molecules are involved in the regulation of migration and proliferation, their expression (lymphocyte function-associated antigen 1 [LFA-1], intercellular adhesion molecule 1 (ICAM-1), L-selectin, alpha4-integrins, CD44, major histocompatability complex class II, interleukin 2 receptor-alpha chain) was determined on B- and T-cell subsets of both groups. B cells, but not T cells, showed a significantly reduced LFA-1 and ICAM-1 expression in blood and lymph nodes, whereas the expression of the other surface molecules analyzed remained unchanged. The down-regulation of these molecules did not influence the adherence of B cells to high endothelial venules in vitro. In vivo, however, ICAM-1(low)-expressing B cells migrated significantly faster through lymph nodes (ICAM-1(low) 41 +/- 5 hours versus ICAM-1(high) 58 +/- 3 hours), whereas proliferation of B cells in bone marrow, lymph node, and blood remained unchanged. Thus, the presence of one organ is necessary for appropriate expression of LFA-1 and ICAM-1 on B cells in other, distant organs. The more rapid transit of ICAM-1(low) B cells through lymph nodes may be responsible for the increased B-cell number in the blood after splenectomy.
Milićević
N M
NM
Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, Yugoslavia.
Luettig
B
B
Trautwein
C
C
Wüstefeld
T
T
Mähler
M
M
Jecker
P
P
Wonigeit
K
K
Westermann
J
J
D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics; D016175:B-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism*; D001773:Blood Cells / Q000276:immunology / Q000378:metabolism; D002448:Cell Adhesion; D002455:Cell Division; D002465:Cell Movement; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000166:cytology; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis / Q000235:genetics; D018960:Hyaluronan Receptors / Q000096:biosynthesis / Q000235:genetics; D016130:Immunophenotyping; D039441:Integrin alpha4; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis* / Q000235:genetics; D019041:L-Selectin / Q000096:biosynthesis / Q000235:genetics; D008198:Lymph Nodes / Q000166:cytology; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D016169:Lymphocyte Function-Associated Antigen-1 / Q000096:biosynthesis* / Q000235:genetics; D008218:Lymphocytosis / Q000209:etiology*; D009928:Organ Specificity; D051381:Rats; D011917:Rats, Inbred Lew; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis / Q000235:genetics; D013156:Splenectomy / Q000009:adverse effects*; D013997:Time Factors
D015703:Antigens, CD; D000949:Histocompatibility Antigens Class II; D018960:Hyaluronan Receptors; D016169:Lymphocyte Function-Associated Antigen-1; D015375:Receptors, Interleukin-2; D018799:Intercellular Adhesion Molecule-1; D019041:L-Selectin; D039441:Integrin alpha4