In vitro characterization of rat bone marrow-derived dendritic cells and their precursors.

Although the rat is commonly used for basic immunology and transplantation research, phenotypic and functional characterization of rat dendritic cells (DCs) lags behind similar studies in the human and mouse. Therefore, these features were examined using DCs propagated from cultures of rat bone marrow maintained in a medium supplemented with granulocyte-monocyte colony-stimulating factor. Analysis of cytospin preparations of cultured cells showd that DCs arise from OX7+ myelomonocytic precursors.

Allogeneic hematolymphoid microchimerism and prevention of autoimmune disease in the rat. A relationship between allo- and autoimmunity.

Conventional allogeneic bone marrow transplantation after myeloablation can prevent experimental autoimmunity and has been proposed as treatment for humans. However, trace populations of donor hematolymphoid cells persisting in solid organ allograft recipients have been associated in some circumstances with therapeutic effects similar to replacement of the entire bone marrow. We therefore examined whether inducing hematolymphoid microchimerism without myeloablation could confer the ability to resist mercuric chloride (HgCl2)-induced autoimmunity.

A new protocol for the propagation of dendritic cells from rat bone marrow using recombinant GM-CSF, and their quantification using the mAb OX-62.

Bone marrow (BM)-derived dendritic cells (DC) are the most potent known antigen (Ag) presenting cell in vivo and in vitro. Detailed analysis of their properties and mechanisms of action requires an ability to produce large numbers of DC. Although DC have been isolated from several rat tissues, including BM, the yield is uniformly low.

Evidence that cyclosporine treatment causes the appearance in rat lymph node of T cells having the antigenic phenotypes of cortical thymocytes.

The antigenic phenotypes and relative size distributions of thymocytes and LN cells from young adult M520 strain rats, injected s.c. with cyclosporine (15 mgm/kg) for 10 consecutive days, were determined by FACS analysis and fluorescence microscopy.

Isolation and characterization of protective T cells induced by Listeria monocytogenes.

Rats convalescing from a recent infection with Listeria monocytogenes generate T cells which can protect recipient rats against a challenge infection with that organism. Using monoclonal antibodies that react with some but not all rat peripheral T cells, the T-cell mediators of acquired resistance to infection (TCRI) were isolated by panning and characterized by using a fluorescence-activated cell sorter. Many L.

Monoclonal antibody analysis of Listeria monocytogenes-induced cytotoxic lymphocytes.

An immunizing infection with Listeria monocytogenes provides a potent stimulus for the formation of prekiller lymphocytes. Their cytolytic potential is revealed when the cells are restimulated in vitro by Listeria antigens. Listeria monocytogenes-induced cytotoxic lymphocytes and the prekiller cells from which they are derived were characterized in respect to their surface antigenic markers.

T-cell co-operation in the mediation of acquired resistance to Listeria monocytogenes.

Monoclonal antibodies were used to select T-cell subsets that mediate delayed-type hypersensitivity (DTH) and acquired cellular resistance (CRI) in rats infected with Listeria monocytogenes. The mediators of DTH were identified as W3/25+ OX8- T cells. The latter comprised a subset distinct from that which could protect recipient rats against a Listeria challenge.

The mediators of acquired resistance to Listeria monocytogenes are contained within a population of cytotoxic T cells.

T cells from peritoneal exudates induced in rats convalescing from a recent infection of Listeria monocytogenes were fractionated into two subsets based on their ability to bind monoclonal antibodies to cell-surface determinants that are expressed on some but not all peripheral T cells. Two phenotypically distinct subsets, one recognized by the antibody MRC OX8 and the other by W3/25, were assayed for their protective capacity in Listeria-challenged recipients, and for their ability to kill unmodified syngeneic fibroblasts in vitro. The two activities were mediated by the OX8+ subset which comprised approximately half the T cells in the exudates.

Activation of Listeria monocytogenes-induced prekiller T cells by interleukin-2.

Thymus-dependent lymphocytes, or T cells, of rats infected with Listeria monocytogenes acquire a potent cytolytic capability when the cells are restimulated in vitro by Listeria antigens. Activation of such Listeria monocytogenes-dependent cytotoxic T lymphocytes requires both antigen and histocompatible accessory cells, but only when the responder T cells have been specifically depleted of lymphocytes that are responsive to accessory cell alloantigens. When unselected T cells are used, significant activation occurs in specific-antigen-free cultures containing allogeneic accessory cells.

The cellular response to Listeria monocytogenes is mediated by a heterogeneous population of immunospecific T cells.

Immunospecific T cells cooperate with macrophages in the expression of delayed type hypersensitivity and cellular resistance to Listeria monocytogenes. The mediator cells involved are generated in response to an immunizing Listeria infection. Immunospecific T cells are formed in lymphoid tissue and appear briefly in the blood.