[show abstract][hide abstract] ABSTRACT: Previously we showed that biodegradable nanoparticles containing poly-IC or CpG oligodeoxynucleotide (ODN) together with ovalbumin (OVA) were efficient at inducing MHC-restricted presentation of OVA peptides in dendritic cells. The CTL-inducing activities of the nanoparticles were examined in the present study. Nanoparticles containing poly-IC or CpG ODN together with OVA were prepared using biodegradable polymer poly(D,L-lactic acid-co-glycolic acid), and then were opsonized with mouse IgG. The nanoparticles were injected into the tail vein of mice, and 7 days later the OVA-specific CTL activities were measured using an in vivo CTL assay. Immunization of mice with the nanoparticles containing poly-IC or CpG ODN together with OVA elicited potent OVA-specific CTL activity compared to those containing OVA only. In accordance with these results, nanoparticles containing poly-IC or CpG ODN together with OVA exerted potent antitumor activity in mice that were subcutaneously implanted with EG7.OVA tumor cells. These results show that encapsulation of poly-IC or CpG ODN together with antigen in biodegradable nanoparticles is an effective approach for the induction of potent antigen-specific CTL responses in vivo.
[show abstract][hide abstract] ABSTRACT: Nanoparticles (NPs) prepared from biodegradable polymers, such as poly (D,L-lactic acid-co-glycolic acid) (PLGA), have been studied as vehicles for the delivery of antigens to phagocytes. This paper describes the preparation of antigen-loaded PLGA-NPs for efficient cross-priming.
NPs containing a similar amount of ovalbumin (OVA) but different sizes were produced using a micromixer-based W/O/W solvent evaporation procedure, and the efficiency of the NPs to induce the cross-presentation of OVA peptides were examined in dendritic cells (DCs). Cellular uptake and biodistribution studies were performed using fluorescein isothiocyanate (FITC)-loaded NPs in mice.
The NPs in the range of 1.1~1.4µm in size were the most and almost equally efficient in inducing the cross-presentation of OVA peptides via H-2K(b) molecules. Cellular uptake and biodistribution studies showed that opsonization of the NPs with mouse IgG greatly increased the percentage of FITC-positive cells in the spleen and lymph nodes. The major cell type of FITC-positive cells in the spleen was macrophages, whereas that of lymph nodes was DCs.
These results show that IgG-opsonized PLGA-NPs with a mean size of 1.1µm would be the choice of biodegradable carriers for the targeted-delivery of protein antigens for cross-priming in vivo.
[show abstract][hide abstract] ABSTRACT: Baccatin III, a precursor for the semisynthesis of taxol, is widely considered to be an inactive derivative of taxol. Here we show that baccatin III efficiently enhances MHC-restricted antigen presentation in dendritic cells. Baccatin III increased both class I- and class II-restricted presentation of exogenous OVA in bone marrow-derived dendritic cells (BM-DCs). Baccatin III also increased class I-restricted presentation of virus-encoded endogenous OVA in BM-DCs. Baccatin III did not affect the phagocytic activity of BM-DCs. The antigen presentation-enhancing activity of baccatin III was examined further with nanoparticles containing OVA and baccatin III. Inclusion of baccatin III to nanoparticles containing OVA greatly enhanced their capacity to induce class I-restricted OVA peptide presentation in DCs both in vitro and in vivo. Accordingly, nanoparticles containing both OVA and baccatin III were much more efficient in inducing an OVA-specific CTL response in mice compared to those containing OVA only. These results demonstrate that baccatin III exerts immunomodulatory activities in vivo as well as in vitro on the MHC-restricted antigen presentation.
International immunopharmacology 02/2011; 11(8):985-91. · 2.21 Impact Factor
[show abstract][hide abstract] ABSTRACT: The effects of intraphagosomal toll-like receptor (TLR) activation on the MHC-restricted presentation of exogenous antigen were examined in dendritic cells (DCs). For phagosomal targeting, nanoparticles containing both a TLR agonist and a model antigen, ovalbumin (OVA), were prepared using biodegradable polymer poly(D,L-lactic acid-co-glycolic acid) and were then opsonized with mouse IgG. After incubating mouse DCs with the nanoparticles, the efficacy of OVA peptide presentation was evaluated using OVA-specific CD8 and CD4 T cells. Inclusion of either the TLR3 agonist poly(I:C) or the TLR9 agonist CpG oligodeoxynucleotides (ODN) significantly increased and prolonged both MHC class I- and class II-restricted OVA presentation. Accordingly, the DCs that phagocytosed the nanoparticles containing poly(I:C) or CpG ODN together with OVA efficiently induced the proliferation of OVA-specific CD8 and CD4 T cells. The potency levels of poly(I:C) and CpG ODN in increasing the MHC-restricted presentation of the exogenous antigen appeared to be similar. A combination of the 2 TLR agonists was synergistic in increasing the MHC class I-restricted, but not the class II-restricted, presentation of exogenous antigen. These results show that IgG-opsonized biodegradable nanoparticles containing both intraphagosomal TLR agonists and antigens can be efficient carrier materials in inducing antigen-specific T cell responses.
Archives of Pharmacal Research 11/2010; 33(11):1859-66. · 1.54 Impact Factor
[show abstract][hide abstract] ABSTRACT: The gels of Aloe species contain immunomodulatory components such as aloctin A and acemannan. Most studies on these gels were performed in in vitro cell culture systems. Although several studies examined their immunomodulatory activity in vivo, the route of administration was intraperitoneal or intramuscular. Here, we evaluated the in vivo immunomodulatory activity of processed Aloe vera gel (PAG) in mice. Oral administration of PAG significantly reduced the growth of C. albicans in the spleen and kidney following intravenous injection of C. albicans in normal mice. PAG administration also reduced the growth of C. albicans in streptozotocin-induced diabetic mice. PAG administration did not increase ovalbumin (OVA)-specific cytotoxic T lymphocyte (CTL) generation in normal mice, but did increase it in high-fat-diet induced diabetic mice. These findings provide the first clear evidence for the immunomodulatory activity of orally administered Aloe vera gel.
Archives of Pharmacal Research 03/2010; 33(3):451-6. · 1.54 Impact Factor
[show abstract][hide abstract] ABSTRACT: The effects of processed Aloe vera gel (PAG) on the course of established diet-induced non-insulin-dependent diabetes mellitus (NIDDM) were studied in C57BL/6J mice. NIDDM was induced in C57BL/6J mice by feeding them a high-fat diet. Mice exhibiting diet-induced obesity (DIO) with blood glucose levels above 180mg/dl were selected to examine the antidiabetic effects of PAG. Oral administration of PAG for 8 weeks reduced circulating blood glucose concentrations to a normal level in these DIO mice. In addition, the administration of PAG significantly decreased plasma insulin. The antidiabetic effects of PAG were also confirmed by intraperitoneal glucose tolerance testing. PAG appeared to lower blood glucose levels by decreasing insulin resistance. The administration of PAG also lowered triacylglyceride levels in liver and plasma. Histological examinations of periepididymal fat pad showed that PAG reduced the average size of adipocytes. These results demonstrate that the oral administration of PAG prevents the progression of NIDDM-related symptoms in high-fat diet-fed mice, and suggest that PAG could be useful for treating NIDDM.
Phytomedicine: international journal of phytotherapy and phytopharmacology 04/2009; 16(9):856-63. · 2.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: Macrophages generated in vitro using macrophage-colony stimulating factor (M-CSF) and interleukin (IL)-6 from bone marrow cells (BM-Mp) are defective in antigen presenting cell (APC) function as shown by their ability to induce the proliferation of anti-CD3 mAb-primed syngeneic T cells. However, they do express major histocompatibility (MHC) class I and II molecules, accessory molecules and intracellular adhesion molecules. Here we demonstrate that the defective APC function of macrophages is mainly due to production of TGF-beta1 by BM-Mp.
Microarray analysis showed that TGF-beta1 was highly expressed in BM-Mp, compared to a macrophage cell line, B6D, which exerted efficient APC function. Production of TGF-beta1 by BM-Mp was confirmed by neutralization experiments of TGF-beta1 as well as by real time-polymerase chain reaction (PCR).
Addition of anti-TGF-beta1 monoclonal antibody to cultures of BM-Mp and anti-CD3 mAb-primed syngeneic T cells efficiently induced the proliferation of syngeneic T cells. Conversely, the APC function of B6D cells was almost completely suppressed by addition of TGF-beta1. Quantitative real time-PCR analysis also confirmed the enhanced expression of TGF-beta1 in BM-Mp.
The defective APC function of macrophages generated in vitro with M-CSF and IL-6 was mainly due to the production of TGF-beta1 by macrophages.
[show abstract][hide abstract] ABSTRACT: APCs, like T cells, are affected by calcineurin inhibitors. In this study, we show that calcineurin inhibitors efficiently block MHC-restricted exogenous Ag presentation in vivo. Mice were injected with clinical doses of tacrolimus (FK-506) followed by soluble OVA, and dendritic cells (DCs) were isolated from lymph nodes and spleens. The efficacy of OVA peptide presentation by DCs was evaluated using OVA-specific CD8 and CD4 T cells. Tacrolimus inhibited both class I- and class II-restricted DC presentation of OVA to T cells. Tacrolimus also inhibited both class I- and class II-restricted presentation of OVA in peritoneal macrophages isolated from mice injected with tacrolimus followed by soluble OVA. Tacrolimus-treated peritoneal macrophages, however, were able to present synthetic OVA peptide, SIINFEKL. Inclusion of cyclosporine A to biodegradable microspheres containing OVA greatly reduced their capacity to induce OVA-specific CTL response in mice. These findings provide novel insight into the mode of action of calcineurin inhibitors and have important implications for clinical immunosuppression regimens.
The Journal of Immunology 12/2007; 179(9):5711-6. · 5.52 Impact Factor
[show abstract][hide abstract] ABSTRACT: Biodegradable nanospheres generated from a biocompatible polymer, poly(D,L-lactide-co-glycolide) (PLGA), have been studied extensively as implantable reservoirs for sustained-release drug delivery. PLGA-nanospheres have also been studied as vehicles to deliver antigens to phagocytes. The intracellular processing pathway of antigens delivered to phagocytes by PLGA particles was studied in the present study. Ovalbumin (OVA) encapsulated with PLGA (OVA-nanosphere) was efficiently captured, processed and presented on class I major histocompatibility complex (MHC-I) by dendritic cells (DCs). The MHC-I processing of OVA-nanospheres was resistant to lactacystin, a proteosome inhibitor, and brefeldin A, which blocks anterograde transport from the endoplasmic reticulum (ER) through the Golgi apparatus. Chloroquine, which inhibits phagolysosomal enzymes by increasing phagolysosomal pH, inhibited MHC-I processing of OVA-nanospheres. In addition, DCs generated from TAP-/- mice were markedly suppressed in MHC-I processing of OVA-nanospheres. These results demonstrate that DCs process phagocytosed OVA-nanospheres via a vacuolar alternate MHC-I pathway for presentation of OVA peptides to T lymphocytes.
Archives of Pharmacal Research 12/2007; 30(11):1440-6. · 1.54 Impact Factor
[show abstract][hide abstract] ABSTRACT: Acharan sulfate isolated from the giant African snail, Achatina fulica, has been reported to have antitumor activity in vivo. In an effort to determine the mechanisms of its antitumor activity, we examined the effects of acharan sulfate on professional antigen presenting cells (APCs). Acharan sulfate increased the phagocytic activity, the production of cytokines such as TNF-alpha and IL-1beta, and the release of nitric oxide on a macrophage cell line, Raw 264.7 cells. In addition, acharan sulfate induced phenotypic and functional maturation of immature dendritic cells (DCs). Immature DCs cultured with acharan sulfate expressed higher levels of class II MHC molecules and major co-stimulatory molecules such as B7-1, B7-2, and CD40. Functional maturation of immature DCs cultured in the presence of acharan sulfate was confirmed by the increased allostimulatory capacity and IL-12 production. These results suggest that the antitumor activity of acharan sulfate is partly due to the activation of professional antigen presenting cells.
Archives of Pharmacal Research 08/2007; 30(7):866-70. · 1.54 Impact Factor
[show abstract][hide abstract] ABSTRACT: The hot water extract of Salicornia herbacea, SHE, has recently been shown to have strong immunomodulatory activity. In the present study, we purified the polysaccharides, termed SHP, from SHE preparation and examined their immunomodulatory activity alone and in combination with interferon (IFN)-gamma. The combination of SHP and IFN-gamma synergistically inhibited the growth of the mouse monocytic cell line, RAW 264.7, inducing further differentiation to strongly adherent macrophages. The differentiation-inducing activity of SHP alone and in combination with IFN-gamma was confirmed by changes in the expression of differentiation antigens such as CD11b, CD18 and CD24. In addition, the combination of SHP and IFN-gamma synergistically activated RAW cells to produce cytokines such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta, and nitric oxide (NO). The synergistic activity of SHP was more prominent when SHP concentration was low. Increased production of TNF-alpha, IL-1 beta and NO was correlated with an increased level of their respective transcripts. These results confirm that Salicornia herbacea contains immunomodulatory polysaccharides that activate monocytes synergistically with small doses of IFN-gamma.
Journal of Ethnopharmacology 06/2007; 111(2):365-70. · 2.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Previous studies have shown that dendritic cells (DCs) can phagocytize, process and present a microencapsulated form of ovalbumin (OVA) in the context of class I MHC as well as class II MHC. In the present study, we examined the effects of recombinant human macrophage-colony stimulating factor (M-CSF) on the MHC-restricted presentation of microencapsulated OVA by DCs. Two types of DCs were generated from mouse bone marrow (BM) cells, one type with granulocyte/macrophage-colony stimulating factor (GM-CSF) alone, the other type with GM-CSF and interleukin (IL)-4. Pretreatment with M-CSF significantly enhanced both class I MHC and class II MHC-restricted presentation of exogenous OVA by both types of DCs. The enhancing activity of M-CSF on antigen presentation was more potent in DCs generated with GM-CSF alone compared to DCs generated with both GM-CSF and IL-4. Pretreatment of the DCs with M-CSF did not increase phagocytic activity or total level of expression of class I MHC (H-2K(b)) molecules, but increased expression of OVA peptide-H-2K(b) complexes upon phagocytosis of microencapsulated OVA. These results demonstrate that M-CSF increases intracellular processing events of phagocytized antigen in DCs.
[show abstract][hide abstract] ABSTRACT: The main targets for the immunosuppressive calcineurin inhibitors, cyclosporin A (CsA) and tacrolimus, have been considered to be activated T cells, but not antigen-presenting cells. Here we demonstrate that CsA and tacrolimus, but not rapamycin, inhibit major histocompatibility complex (MHC)-restricted antigen presentation in dendritic cells (DCs). Microencapsulated ovalbumin (OVA) was efficiently captured, processed, and presented on both class I MHC molecules (cross-presentation) as well as on class II MHC molecules. Addition of CsA and tacrolimus, but not rapamycin, to cultures of DCs inhibited both the class I processing pathway and the class II processing pathway of exogenous OVA. In addition, CsA and tacrolimus, but not rapamycin, also inhibited the classic class I processing pathway of endogenous OVA. CsA and tacrolimus did not inhibit presentation of exogenously added OVA peptide, SIINFEKL, phagocytic activity of DCs, or the total level of expression of class I MHC (H-2Kb) molecules. CsA and tacrolimus, however, inhibited profoundly the expression of SIINFEKL-H-2Kb complexes in OVA-phagocytized DCs. These results demonstrate clearly that CsA and tacrolimus inhibit intracellular processing events of antigens, and further suggest that the immunosuppressive activity of CsA and tacrolimus is at least in part due to inhibition of antigen processing pathways.
[show abstract][hide abstract] ABSTRACT: Macrophages generated with macrophage-colony stimulating factor (M-CSF) are defective in antigen presenting cell (APC) function, although they do express major histocompatibility (MHC) class II molecules, numerous accessory molecules, and intercellular adhesion molecules. In the present study, we show evidence that the acquisition of APC function is influenced significantly by microenvironmental condition of development. Macrophages generated from bone marrow progenitor cells with M-CSF and interleukin (IL)-6 were defective in APC function as determined by their ability to induce anti-CD3 monoclonal antibody (mAb)-primed T cell proliferation. Macrophages generated in the presence of some of the CC chemokines such as leukotactin-1, macrophage inflammatory protein (MIP)-1alpha, and RANTES together with M-CSF and IL-6, however, induced proliferation of anti-CD3 mAb-primed T cells. Maximum level of APC function was obtained when developing macrophages were exposed with the chemokines at the late stage of maturation. Enhanced APC function of the macrophages appeared to be correlated with the expression of co-stimulatory molecules and the ability to produce cytokines. These results suggest that the acquisition of APC function of mature macrophage is modulated significantly by the microenvironmental condition during development.