Ethanol induces the formation of water-permeable defects in model bilayers of skin lipids

We observe that ethanol can induce the formation of water-permeable defects in model bilayers of skin lipids and propose this as a new mechanism of action of ethanol as a membrane modulator.

Comparison of the immunogenicity of Montanide ISA 51 adjuvant and cytokine-matured dendritic cells in a randomized controlled clinical trial of melanoma vaccines

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Background: Dendritic cell (DC) vaccines have been widely used in clinical trials to treat cancer. However, no study has compared the immunogenicity of the most commonly used DC type (cytokine-matured, monocyte-derived DCs) to more traditional vaccine adjuvants. We performed a randomized controlled trial comparing the immunogenicity of cytokine-matured DCs loaded with 6 HLA-A2-restricted peptide antigens and a foreign protein, KLH, to a vaccine containing the same antigens emulsified in the mineral oil adjuvant Montanide ISA 51 VG. Methods: 51 HLA-A2+ patients with resected stage IIb-IIIc melanoma were randomized to receive DCs (25 patients) or Montanide (26 patients). DCs were differentiated from autologous blood monocytes with IL-4 and GM-CSF, then matured with IL- 1β, IL-6, TNFα and PGE2. 18 million DCs were given i.d. every 4 weeks x 4, and immune responses analyzed (MHC multimers, T cell proliferation, cytokine secretion, antibodies). A 3-fold increase over baseline was considered a response. Results: Both vaccines were well tolerated. Immunogenicity was significantly greater with Montanide, as demonstrated by response rates to Flu, Melan-A and NY-ESO-1 peptides by IFNγ ELISPOT. Similar results were obtained by MHC multimer staining, with higher response rates seen using pre-sensitized assays. T cell proliferation to KLH was seen in both arms (90% DC, 100% Montanide), but the magnitude of response was significantly higher for Montanide (36-fold vs. 14-fold increase over baseline, p=0.002, Wilcoxon). KLH-specific CD4+ T cells that produced IFNγ, TNFα and IL-2 were seen only with Montanide, and all Montanide patients, but only 5% of DC patients, developed antibodies to KLH (p<0.001, Fisher's). Conclusions: A water-in-oil vaccine adjuvant, Montanide ISA 51, was significantly more immunogenic than DCs. Future studies of new DC vaccines should compare DCs to standard adjuvants to determine if their added difficulty and expense are truly warranted.

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An ikaros-containing chromatin-remodeling complex in adult-type erythroid cells

We have previously described a SWI/SNF-related protein complex (PYR complex) that is restricted to definitive (adult-type) hematopoietic cells and that specifically binds DNA sequences containing long stretches of pyrimidines. Deletion of an intergenic DNA-binding site for this complex from a human beta-globin locus construct results in delayed human gamma- to beta-globin switching in transgenic mice, suggesting that the PYR complex acts to facilitate the switch. We now show that PYR complex DNA-binding activity also copurifies with subunits of a second type of chromatin-remodeling complex, nucleosome-remodeling deacetylase (NuRD), that has been shown to have both nucleosome-remodeling and histone deacetylase activities. Gel supershift assays using antibodies to the ATPase-helicase subunit of the NuRD complex, Mi-2 (CHD4), confirm that Mi-2 is a component of the PYR complex. In addition, we show that the hematopoietic cell-restricted zinc finger protein Ikaros copurifies with PYR complex DNA-binding activity and that antibodies to Ikaros also supershift the complex. We also show that NuRD and SWI/SNF components coimmunopurify with each other as well as with Ikaros. Competition gel shift experiments using partially purified PYR complex and recombinant Ikaros protein indicate that Ikaros functions as a DNA-binding subunit of the PYR complex. Our results suggest that Ikaros targets two types of chromatin-remodeling factors-activators (SWI/SNF) and repressors (NuRD)-in a single complex (PYR complex) to the beta-globin locus in adult erythroid cells. At the time of the switch from fetal to adult globin production, the PYR complex is assembled and may function to repress gamma-globin gene expression and facilitate gamma- to beta-globin switching.