Induction of regulatory T cells from mature T cells by allogeneic thymic epithelial cells in vitro.

The ability of thymic epithelial cells (TEC) to re-educate mature T cells to be regulatory T cells has not been addressed. In the present study, this issue was directly investigated by co-culturing of mature T cells and allo-TECs. B6 macrophage cell line 1C21-cultured BALB/c splenocytes responded to B6 antigens in vitro.

Altered allogeneic immune responses in middle-aged mice.

It is well known that leukocyte composition, T cell phenotypes and immune function change in aged mice and humans. However, limited and conflicting results on the age-related immune changes in middle-aged mice were reported. Identification of the characteristics of allogeneic immune responses in aging mice may offer important information for transplantation immunology.

The interaction defect of accessory molecules is responsible for the poor ex vivo response to human antigens of mouse T helper cells.

Mouse T cells fail to respond to xenogeneic pig and human antigens using the direct antigen-presenting pathway. The poor response by mouse CD8 cells is because of multiple defects in the molecular interactions between mouse CD8 cells and xenogeneic antigen-presenting cells (APCs). Using human CD4/DR3+, mouse CD4-/major histocompatibility complex (MHC) class II - mice, we investigated the defects in molecular interaction responsible for the poor response to xenogeneic antigens by naïve mouse CD4+ cells.

Xenogeneic skin graft rejection in M-CSF/macrophage deficient osteopetrotic mice.

Background: The cellular infiltrate in xenografts suggests that macrophages may be involved in xenograft rejection. However, the precise role of macrophages in xenograft rejection has not yet been fully addressed.

Methods: Xenogeneic rat skin grafts were transplanted to macrophage colony stimulating factor (M-CSF)/macrophage-deficient osteopetrotic ([OP]-/-) and wild-type control mice.

Prolongation of allogeneic skin graft survival by injection of anti-Ly49A monoclonal antibody YE1/48.

Ly49A receptors expressed on NK, NKT, and T cells play inhibitory roles in regulating the immune responses in vivo and in vitro. Whether or not injection of anti-Ly49A monoclonal antibody (mAb) YE1/48 can block allograft rejection has not been evaluated. Balb/c mouse recipients received intraperitoneal injections of YE1/48 mAb (0.