BONE MARROW-DERIVED DENDRITIC CELL PROGENITORS (NLDC 145+, MHC CLASS II+, B7-1dim, B7-2−) INDUCE ALLOANTIGEN-SPECIFIC HYPORESPONSIVENESS IN MURINE T LYMPHOCYTES1,2

Abstract

The functional maturation of dendritic cells (DC) and other antigen-presenting cells is believed to reflect the upregulation of cell surface major histocompatibility complex (MHC) class II and other T cell costimulatory molecules, especially the CD28 ligands B7-1 (CD80) and B7-2 (CD86). In this study, we propagated cells exhibiting characteristics of DC precursors from the bone marrow (BM) of BIO mice (H_2 b ; I-A +) in response to granulocyte-macrophage colony stimulating factor (GM-CSF). The methods used were similar to those employed previously to propagate DC progenitors from normal mouse liver. Cells expressing DC lineage markers (NLDC 145+, 33Dl +, N418+) harvested from 8-tO-day GM-CSF stimulated BM cell cultures were CD45+, heat-stable antigen+, CD54+, CD44+, MHC class 11+, B7_1 dbn but B7-2-(costimulatory molecule-deficient). Supplementation of cultures with interleukin-4 (IL-4) in addition to GM-CSF however, resulted in marked upregulation of MHC class II and B7-2 expression. These latter cells exhibited potent allostimulatory activity in primary mixed leukocyte cultures. In contrast, the cells stimulated with GM-CSF alone were relatively weak stimulators and induced alloantigen-specific hyporesponsiveness in allogeneic T cells (C3H; H_2k; I-E+) detected upon restimulation in secondary MLR. This was associated with blockade of IL-2 production. Reactivity to thirdparty stimulators was intact. The hyporesponsiveness induced by the GM-CSF stimulated, costimulatory molecule-deficient cells was prevented by incorporation of anti-CD28 monoclonal antibody in the primary MLR and was reversed by addition of IL-2 to restimulated T cells. The findings show that MHC class 11+ B7-2-cells with a DC precursor phenotype can induce alloantigen-specific hyporesponsiveness in vitro. Under the appropriate conditions, such costimulatory molecule-deficient cells could contribute to the induction of donor-specific unresponsiveness in vivo.

Adenoviral delivery of CTLA4Ig into myeloid dendritic cells promotes their in vitro tolerogenicity and survival in allogeneic recipients

“…2,4 Maximizing the tolerogenic potential of DC by means that may include their genetic manipulation, offers a potential novel approach to the therapy of immune-mediated disorders, including allograft rejection, autoimmune disease and allergy. Indeed, there is already evidence that immature DC, 8,19 or DC exposed to ultraviolet (UV) irradiation 20 or immunosuppressive molecules (such as IL-10, transforming growth factor ␤ (TGF␤), or CTLA4Ig) 19,[21][22][23] have tolerogenic potential. DC that are inherently deficient in cell surface expression of costimulatory molecules can induce T cell hyporesponsiveness in vitro and prolong allograft survival.…”

“…The interaction of CD28 on T cells with B7 ligands on APC provides an essential second signal for T cell activation. [5][6][7] Immature DC, deficient in these molecules (DC progenitors) and that resemble DC freshly isolated from non-lymphoid tissues, can induce antigen-specific T cell anergy in vitro 8 and prolong the survival of cardiac 9 or pancreatic islet allografts. 10 Although these DC exhibit tolerogenic potential, they do not induce permanent graft acceptance.…”

A new type of genetic regulation of allogeneic response. A novel locus on mouse chromosome 4, Alan2 controls MLC reactivity to three different alloantigens: C57BL/10, BALB/c and CBA

“…In this segment is localized Csf3r (colony stimulating factor 3 receptor (granulocyte)) (http://www.informatics.jax.org./). GM-CSF influences MLC response, 6 but no influence of a polymorphism in Csf3r on MLR has been described.…”

“…1 Another secondary costimulatory signal is an interaction of CD40 on APC with CD40L on T cell. 2 As the strongest proliferative stimulus is generated by class II incompatibility, the principal MLR responding cells are CD4 + T cells, but other immunoregulatory cells and their products, such as IL-1, IL-6, 3 IL-2, IFN␥, IL-4, 4 IL-10, 5 GM-CSF, 6 NO 7 can quantitatively influence the response. Data about influence of some of these factors are often contradictory.…”

Reduced antigen concentration and costimulatory blockade increase IFN‐γ secretion in naive CD8+ T cells

“…Studies of DC have been greatly facilitated by their generation from progenitors in bone marrow (BM), spleen or blood [13][14][15]. Most protocols include the growth factor GM-CSF but other factors further induce expression of MHC and costimulatory molecules on the DC [16][17][18]. One such factor is IL-4.…”