Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although exogeneous "danger" signals such as LPS can activate APC to produce a Th1 response, the nature of events initiating a Th2 response is controversial. We now show that pathogen-derived products have the capacity to induce bone marrow-derived dendritic cell cultures to acquire a phenotype that promotes the differentiation of naive CD4+ T cells toward either a Th1 or Th2 phenotype. Thus, LPS-matured dendritic cells (DC1) promote a Th1 response (increased generation of IFN-gamma and reduced production of IL-4) by Ag-stimulated CD4+ T cells from the DO.11.10 transgenic mouse expressing a TCR specific for an OVA peptide (OVA323-339). In contrast, a phosphorylcholine-containing glycoprotein, ES-62, secreted by the filarial nematode, Acanthocheilonema viteae, which generates a Th2 Ab response in vivo, is found to induce the maturation of dendritic cells (DC2) with the capacity to induce Th2 responses (increased IL-4 and decreased IFN-gamma). In addition, we show that the switch to either Th1 or Th2 responses is not effected by differential regulation through CD80 or CD86 and that a Th2 response is achieved in the presence of IL-12.
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PMID:A filarial nematode-secreted product signals dendritic cells to acquire a phenotype that drives development of Th2 cells. 1084 1

Experiments were designed to examine whether administration of APC at the site of HPV 16-associated tumours can inhibit tumour growth and whether the efficacy of established dendritic cell lines is comparable to that of fresh BMDC populations. Mice were inoculated s.c. with APC, either bone marrow-derived dendritic cells differentiated in medium supplemented with GM-CSF and IL-4 (BMDC), or with established dendritic cell lines DC2.4 or JAWS II. The pretreated mice, together with untreated controls, were challenged with syngeneic HPV 16-transformed cells MK16 at the site of APC administration. It has been found that both BMDC and dendritic cell lines can inhibit tumour growth and that the efficacy of the established dendritic cell lines DC2.4 and JAWS II was comparable to that of fresh BMDC populations. In vitro induction of proliferative spleen cell responses by co-cultivation with MK16 antigen-pulsed BMDC or MK16 antigen-pulsed dendritic cell lines revealed that both types of APC populations can prime immune reactions directed against syngeneic HPV 16-associated neoplasms. Taken together, the results suggest that local increase in the number of dendritic cells at the site of HPV 16-associated tumours can inhibit progression of the tumours and that the dendritic cell lines which are efficient in this respect can be considered and should be tested in both, preclinical and human systems for delivery of therapeutic vaccines against HPV 16-associated neoplasms.
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PMID:Tumour-inhibitory effects of dendritic cells administered at the site of HPV 16-induced neoplasms. 1211 25

Cell surface gangliosides are shed by tumors into their microenvironment. In this study they inhibit cellular immune responses, including APC development and function, which is critical for Th1 and Th2 cell development. Using human dendritic cells (DCs) and naive CD4(+) T cells, we separately evaluated Th1 and Th2 development under the selective differentiating pressures of DC1-inducing pertussis toxin (PT) and DC2-inducing cholera toxin (CT). High DC IL-12 production after PT exposure and high DC IL-10 production after CT exposure were observed, as expected. However, when DCs were first preincubated with highly purified G(D1a) ganglioside, up-regulation of costimulatory molecules was blunted, and PT-induced IL-12 production was reduced, whereas CT-induced IL-10 production was increased. The combination of these effects could contribute to a block in the Th1 response. In fact, when untreated naive T cells were coincubated with ganglioside-preincubated, Ag-exposed DCs, naive Th cell differentiation into Th effector cells was reduced. Both the subsequent DC1-induced T cell production of IFN-gamma (Th1 marker) and DC2-induced T cell IL-4 production (Th2) were inhibited. Thus, ganglioside exposure of DC impairs, by at least two distinct mechanisms, the ability to induce Th differentiation, which could adversely affect the development of an effective cellular antitumor immune response.
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PMID:Modulation of CD4 Th cell differentiation by ganglioside GD1a in vitro. 1621 May 94

In situ modification of antigen-presenting cells garnered interest in cancer immunotherapy. Therefore, we developed APC-targeted lentiviral vectors (LVs). Unexpectedly, these LVs were inferior vaccines to broad tropism LVs. Since IL-12 is a potent mediator of antitumor immunity, we evaluated whether this proinflammatory cytokine could enhance antitumor immunity of an APC-targeted LV-based vaccine. Therefore, we compared subcutaneous administration of broad tropism LVs (VSV-G-LV) with APC-targeted LVs (DC2.1-LV)-encoding enhanced GFP and ovalbumin, or IL-12 and ovalbumin in mice. We show that codelivery of IL-12 by VSV-G-LVs or DC2.1-LVs augments CD4(+) or CD8(+) T-cell proliferation, respectively. Furthermore, we demonstrate that codelivery of IL-12 enhances the CD4(+) TH 1 profile irrespective of its delivery mode, while an increase in cytotoxic and therapeutic CD8(+) T cells was only induced upon VSV-G-LV injection. While codelivery of IL-12 by DC2.1-LVs did not enhance CD8(+) T-cell performance, it increased expression of inhibitory checkpoint markers Lag3, Tim3, and PD-1. Finally, the discrepancy between CD4(+) T-cell stimulation with and without functional CD8(+) T-cell stimulation by VSV-G- and DC2.1-LVs is partly explained by the observation that IL-12 relieves CD8(+) T cells from CD4(+) T-cell help, implying that a T(H)1 profile is of minor importance for antitumor immunotherapy if IL-12 is exogenously delivered.
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PMID:The transduction pattern of IL-12-encoding lentiviral vectors shapes the immunological outcome. 2637 33