Splenectomy does not influence adherence of B cells to HEVs in vitro or B-cell proliferation in vivo.
(A) After incubation of blood and standard cells on a mesenteric lymph node cryostat section the adherence on HEVs was demonstrated and B cells (blue) and standard lymphocytes (brown) were identified immunohistochemically. Co indicates cortex; pa, paracortex; gc, germinal center; HEV, high endothelial venule, framed. Original magnification × 250. (B) Depicted is the framed HEV that is shown in panel A. The standard cells are visible in brown. The black arrows demonstrate blood B cells, the black arrowhead a blood non-B cell, the white arrow a standard B cell, and the open arrowhead a standard non-B cell. Original magnification × 500. (C) The adherence on parathymic (para), axillary (ax), cervical (cerv), and mesenteric (mes) lymph nodes and Peyer patches is shown for control and splenectomized animals. On tissue from control animals blood B cells from control animals were used, and on tissue from splenectomized rats blood B cells from splenectomized rats were used. The values are given as the mean of the adherence ratio ± SD (n = 6 for each group). (D) Cytospot of bone marrow cells is depicted. Bone marrow cells were isolated 1 hour after BrdU injection. B cells that were IgM positive (black arrowhead), proliferating B cells that had incorporated BrdU (black arrow), proliferating non-B cells (white arrow), and nonproliferating non-B cells (white arrowhead) are shown. (E) Mesenteric lymph nodes were removed 1 hour after BrdU injection and tissue sections were stained for B cells and BrdU incorporation. The black arrows show proliferating B cells (original magnification D: × 600 and E: × 150; co indicates cortex; pa, paracortex). (F) The graph demonstrates the number of proliferating IgD+ and IgM+ B cells in the bone marrow of control and splenectomized rats. (G) Indicated is the number of B cells per area (mm2 × 1000) proliferating in the B-cell area in control versus splenectomized rats. For panels F and G the mean ± SD are given (n = 4-5 for each group).
