Dendritic cells induce T cell proliferation to synthetic antigens under Ir gene control.

Abstract

There has been much debate as to the exact nature of the antigen-presenting accessory cell in various immunological reactions such as T cell proliferation and help (1). It has been suggested that the accessory cell bears Ia antigen on its surface (2). These antigens characterize some but not all macrophages; conversely, they are not unique macrophage markers (3). The dendritic cell of Steinman and Cohn has recently been described as expressing Ia antigens and being a potent stimulator of ailogeneic T cell proliferation (4, 5). We were interested in determining if this dendritic cell might be important in presenting antigen to syngeneic T cells.We have found that dendritic cells are strongly I-A positive and are highly efficient at presenting soluble antigens to syngeneic T cells. Furthermore this antigen presentation is under immune response (Ir) gene control as dendritic cells from nonresponder strains do not induce proliferation in responder × nonresponder Fa T cells. Cell Fractionation. Dendritic cell preparation was based on that of Steinman and Cohn (4-6) with minor modifications. Initial fractionation of spleen and lymph node suspensions was on discontinuous bovine serum albumin gradients (7) (Path-O-Cyte 4; Miles Laboratories, Inc., Kankakee, Ill.) rather than a single-step procedure. The lightest (A) layer, separating at the interface of 10 and 23% albumin after spinning at 18,000 g,v for 30 min, was used as the starting population. It constituted <1% of the original spleen and lymph node. A layer cells were cultured for 2 h at 37°C as described previously (4, 5); nonadherent cells were then removed by aspiration, and the adherent cells left for a further 18 h in culture. Materials and Methods MiceFc receptor (FcR) rosetting was performed on the nonadherent cells at 18 h using anti-sheep erythrocyte antibody (7S IgG; Cordis Laboratories Inc., Miami, Fla.) -coated sheep erythrocytes. This cell mixture was spun on a Ficoll-Hypaque gradient (20°C for 30 min at 400 gay) to separate nonrosetted (FcR-) from rosetted (FcR +) populations. Both interface and pelleted populations were treated with 0.83% ammonium chloride in Tris buffer, pH 7.6, for 5 rain to lyse erythrocytes and washed twice in supplemented medium (vide infra). Dendritic cells are the interface (FcR-) cells and constitute between 0.2 and 0.5% of the original starting nucleated cell population in agreement with the previously described yield (6).Cells adherent after 18 h in culture were removed by 10 mM EDTA and vigorous pipetting. These represent the 18-h-adherent fraction of the original population.

Human dermal fibroblasts present tetanus toxoid antigen to antigen-specific T cell clones.

“…These long-term cloned T cells have been cultured by repeated stimulation (every 7-10 d) with TT in the presence of irradiated autologous PBMC with IL-2-containing supernatants, and were shown to proliferate on exposure to TT in the context of specific HLA-DR antigens on monocytes. Table I shows that significant proliferation of cloned T cells occurred in the presence of TT antigen and autologous monocytes, or with TT and autologous fibroblasts that were pretreated with IFN-'y (lines [3][4][5][6]. Whenever examined in the same experiment, the extent of T cell proliferation to IFN-'ytreated fibroblasts plus TT was similar to that seen in the presence of autologous monocytes (Table I).…”

“…Macrophages, as well as epidermal Langerhan's cells (1)(2)(3), dendritic cells of lymphoid organs (4,5), some lymphoblastoid B cell lines (6)(7)(8), vascular endothelial cells (3,9), and brain astrocytes (10), are capable of AC function and antigen presentation. All of these cells display surface Class II major histocompatibility complex (MHC) antigens (HLA-DR, DP, DQ, or Ia antigens), which are recognized by the responding T cell.…”

Recurrences and Relation to Tumor Growth Potential and Local Immune Response in Node-Negative Advanced Gastric Cancer

“…Dendritic cells belong to an immunological dendritic cell lineage, recognized as Langerhans’ cells or indeterminate cells in the skin, and as interdigitating cells in lymph nodes, spleen or thymic medulla [24, 25]. These cells function as accessory cells which present antigens to sensitized T cells [26, 27]. As T lymphocytes play a main role in antitumor cytotoxity, dendritic cells infiltrating a tumor are assumed to represent an ongoing immune response against the tumor [28, 29].…”

Vitamin A Acetate as a Regulator of Accessory Cell Function in Delayed-Type Hypersensitivity Responses

“…The low density non-adherent fractions were separated into dendri tic and macrophage populations according to a standard protocol [12]. Briefly, the cell layer separating at the interface of 10 and 23% albumin (after spinning at 18,000 g for 30 min), was cultured for 2 h at 37°C, non-adherent cells were then removed by aspiration and the adherent cells left for a further 18 h in culture.…”