Control of primary IgM antibody responses to H‐2 alloantigens by antigen‐bearing live B lymphocytes

Abstract

Alloantigen-bearing (H-2d+) peripheral red blood cells, but not red cell-depleted H-2d+ spleen cells, induce primary IgM anti-H-2d plaque-forming cell responses. In this study it is reported that the primary antibody responses to H-2d+ peripheral red blood cells can be markedly suppressed by a subpopulation of H-2d+ spleen cells when they are injected simultaneously or a few days before injection of red blood cells. This suppression was antigen (H-2d)-specific, did not depend on T cells of either the donor or the recipient, and strictly required live donor cells. An energy-dependent action of the donor cell cortex and some proliferation of donor cells in the recipient seemed to be involved in the mechanism of suppression. The donor-suppressor cell type was largely present in the spleen but not in the bone marrow and thymus, and was present in the spleen of athymic nude mice. The suppressor cells displayed the properties of B lymphocytes: they adhered to the nylon wool but not to glass, were of relatively low density (rho less than 1.09), and were surface Ig+, Ia+, Fc receptor-positive but Thy-1-. H-2d+ suppressor-donor B lymphocytes might directly signal to antigen-specific recipient B cells competing with the signal provided by H-2d+ red blood cells for the B cell activation.

Direct evidence of involvement of glycosylphosphatidylinositol‐anchored proteins in the heavy metal‐mediated signal delivery into T lymphocytes

“…Single cell suspensions of thymocytes in MEM were prepared from C57BL/6 mice as described previously [20]. Murine thymoma cell line BW5147 of AKR mouse origin and its Thy-1-mutant class A (Thy-l-a) defective in PIG-A [21,22], were donated by Dr. R. Hyman, Salk Institute, through Dr. T. Kinoshita, Osaka Univesrsity.…”

Paeoniflorin induces apoptosis of lymphocytes through a redox‐linked mechanism

“…Single cell suspensions of murine thymocytes and splenocytes were prepared from 6-to 8-weekold C57BL/6 strain mice. Splenic T cells (a Tcell-enriched fraction) were obtained by passing spleen cells through a nylon wool column according to the technique described previously [Nakashima et al, 1982]. A Jurkat cell line (human T-cell leukemia cells), a NIH 3T3 cell line (murine fibroblasts), a SK Hep1 cell line (human hepatoma cells) and a COS-7 cell line (monkey kidney fibroblasts) were also used.…”

Inhibition of Fas‐mediated apoptotic cell death of murine T lymphocytes in a mouse model of immunosenescence in linkage to deterioration in cell membrane raft function

“…Single cell suspensions were obtained from spleens of mice as described previously. A T‐cell enriched fraction was prepared by passing the spleen cell suspensions through a nylon wool column as described elsewhere 13 . The percentage of Thy‐1 + T cells in this fraction was >85% when measured after staining the cells with Thy‐1.2‐fluoroscein isothiocyanate (FITC) (see below).…”