ABSTRACT
Objective To observe the effects of PTD-hepatitis B core antigen (HBcAg) induced murine bone marrow-derived dendritic cells (DCs) maturation on T lymphocyte proliferation in vitro.Methods Bone marrow derived DCs isolated from BALB/c mice were cultured with recombinant granu|ocyte-macrophage colony-stimulating factor (rGM-CSF) and recombinant interleutin-4 (rIL-4)for 5 days.Tumor necrosis factor (TNF)-a,HBcAg and PTD-HBcAg were added to induce DCs maturation.The distribution and localization of intracellular immunofluorescence were observed by confocal microscopy,and DCs phenotypes were analyzed by flow cytometry.The level of IL-12 p70 in the supernatant was detected by enzyme linked immunosorhent assay (ELISA).The proliferation of T lymphocytes was performed by using cell counting kit-8 (CCK-8).All data were analyzed using t test.Results DCs were cultured and identified successfully.Recombinant PTD-HBcAg could penetrate into DCs cytoplasm while recombinant HBcAg was detected on the surface of cells.DCs surface molecules,such as CD80,CD86 and major histocompability complex (MHC) II were upregulated by PTDHBcAg;IL-12 p70 levels induced by 50 mg/L and 100 mg/L recombinant PTD-HBcAg were (142.50±18.31) ng/L and (124.30±15.12) ng/L,respectively,which were significantly higher than those induced by recombinant HBcAg [(42.31±4.21 ) ng/L,t = 9.234 and 9.045,respectively,P＜0.05].The proliferation of T lymphocytes induced by PTD-HBcAg was much higher than that in HBcAg group or positive control TNF-a group.Conclusions PTD-HBcAg could penetrate membrane of DCs and promote the differentiation and maturation of DCs.PTD-HBcAg could up-regulate the expressions of costimulatory molecules on cell surface of DCs,and enhance the ability of DCs on stimulating T lymphocytes proliferation and IL-12 p70 production.
ABSTRACT
Membrane penetration depth is an important parameter in relation to membrane structure and organization. A methodology has been developed to analyze the membrane penetration depths of fluorescent molecules or groups utilizing differential fluorescence quenching caused by membrane embedded spin-label probes located at different depths. The method involves determination of the parallax in the apparent location of fluorophores, detected when quenching by phospholipids spin-labelled at two different depths is compared. By use of relatively simple algebraic expressions, the method allows calculation of depth in Å. This method has been used to determine the location of fluorophores in NBD-labelled lipids and anthroyloxy-labelled fatty acids in model membranes and of the membrane embedded tryptophan residues in the reconstituted nicotinic acetylcholine receptor.