Enhanced cytotoxicity and decreased CD8 dependence of human cancer-specific cytotoxic T lymphocytes after vaccination with low peptide dose

In mice, vaccination with high peptide doses generates higher frequencies of specific CD8+ T cells, but with lower avidity compared to vaccination with lower peptide doses. To investigate the impact of peptide dose on CD8+ T cell responses in humans, melanoma patients were vaccinated with 0.1 or 0.5?mg Melan-A/MART-1 peptide, mixed with CpG 7909 and Incomplete Freund's adjuvant. Neither the kinetics nor the amplitude of the Melan-A-specific CD8+ T cell responses differed between the two vaccination groups. Also, CD8+ T cell differentiation and cytokine production ex vivo were similar in the two groups. Interestingly, after low peptide dose vaccination, Melan-A-specific CD8+ T cells showed enhanced degranulation upon peptide stimulation, as assessed by CD107a upregulation and perforin release ex vivo. In accordance, CD8+ T cell clones derived from low peptide dose-vaccinated patients showed significantly increased degranulation and stronger cytotoxicity. In parallel, Melan-A-specific CD8+ T cells and clones from low peptide dose-vaccinated patients expressed lower CD8 levels, despite similar or even stronger binding to tetramers. Furthermore, CD8+ T cell clones from low peptide dose-vaccinated patients bound CD8 binding-deficient tetramers more efficiently, suggesting that they may express higher affinity TCRs. We conclude that low peptide dose vaccination generated CD8+ T cell responses with stronger cytotoxicity and lower CD8 dependence.     

Polymorphisms of vitamin D receptor gene in the population of eastern Croatia with psoriasis vulgaris and diabetes mellitus

The aim of this study was to evaluate the possible association between polymorphisms in the Vitamin D receptor gene (VDR gene) and tendency for development of psoriasis vulgaris and diabetes mellitus in the population of Slavonia, which is a region in the Eastern Croatia. In order to conduct the mentioned evaluation the restriction fragment length polymorphisms (ApaI, BsmI and TaqI) in the Vitamin D receptor gene were researched in three groups of patients: patients suffering only from psoriasis vulgaris, patients suffering only from diabetes mellitus, and patients suffering at the same time from both diseases. Four most common genotypes were found in all standardized control patients: triple heterozygotes BbAaTt (in 29.3% of the studied patients), bbAaTT (in 18.6% of the studied patients), bbaaTT (in 12.9% of the studied patients) and BbAATt (in 8.6% of the studied patients). Three most common VDR 3'-RFLP haplotypes determined in this study were: three-component baT, Bat and bAT haplotype. Results of the Hardy-Weinberg equilibrium showed presence of BsmI polymorphism genotype frequencies disequilibrium in the group of patients suffering from psoriasis and ApaI polymorphism in the group of patients suffering from both diseases. According to the same statistical test all conditions for TaqI polymorphism genotype frequency were fulfilled in all groups of studied patients. There was no significant difference in distribution of BsmI, ApaI or TaqI polymorphism genotype frequencies between control patients and any of the subgroup of studied patients. In studied population none of analysed polymorphisms individually was associated with the risk of development of psoriasis, diabetes or combined phenotype.     

The effect of fucoidan from brown seaweed Sargassum wightii on WSSV resistance and immune activity in shrimp Penaeus monodon (Fab)

The polysaccharide-fucoidan was extracted from brown seaweed Sargassum wightii and characterized through FT-IR and ¹³C & ¹H NMR analysis. The extracted fucoidan was supplemented with pellet diets at three different concentrations (0.1, 0.2 and 0.3%). The fucoidan supplemented diets were fed to Penaeus monodon for 45 days, then challenged with WSSV and the mortality percentage was recorded daily up to 21 days. During the challenge test, the control group showed 100% mortality within 10 days, but in the experimental groups, the mortality percentage (51-72% within 21 days) was decreased considerably (P < 0.05) with respect to the concentrations of fucoidan. The reduction in mortality percentage of experimental groups over control group was ranged from 50.81 to 68.06%. During challenge experiment, the immunological parameters such as THC, prophenoloxidase activity, respiratory burst activity, superoxide dismutase activity and phagocytic activity were measured before injection of WSSV (0 day) and after the injection of WSSV on 10th and 21st days, respectively. All the immunological parameters of experimental groups were significantly (P < 0.05) increased than control group. RT-PCR analysis confirmed the considerable reduction of WSSV DNA copy numbers with respect to the concentration of fucoidan. It was concluded that P. monodon fed with fucoidan of S. wightii supplemented diet had enhanced the innate immunity and increased resistance against WSSV infection.     

The T cell receptor's alpha-chain connecting peptide motif promotes close approximation of the CD8 coreceptor allowing efficient signal initiation

The CD8 coreceptor contributes to the recognition of peptide-MHC (pMHC) ligands by stabilizing the TCR-pMHC interaction and enabling efficient signaling initiation. It is unclear though, which structural elements of the TCR ensure a productive association of the coreceptor. The alpha-chain connecting peptide motif (alpha-CPM) is a highly conserved sequence of eight amino acids in the membrane proximal region of the TCR alpha-chain. TCRs lacking the alpha-CPM respond poorly to low-affinity pMHC ligands and are unable to induce positive thymic selection. In this study we show that CD8 participation in ligand binding is compromised in T lineage cells expressing mutant alpha-CPM TCRs, leading to a slight reduction in apparent affinity; however, this by itself does not explain the thymic selection defect. By fluorescence resonance energy transfer microscopy, we found that TCR-CD8 association was compromised for TCRs lacking the alpha-CPM. Although high-affinity (negative-selecting) pMHC ligands showed reduced TCR-CD8 interaction, low-affinity (positive-selecting) ligands completely failed to induce molecular approximation of the TCR and its coreceptor. Therefore, the alpha-CPM of a TCR is an important element in mediating CD8 approximation and signal initiation.     

Suture dehiscence and collagen content in the human mitral and tricuspid annuli

Biomechanics and Modeling in Mechanobiology - Postoperative suture dehiscence is an important mode of short-term mitral and tricuspid valve (MV, TV) repair failure. We sought to evaluate suture...     

The SIT4 protein phosphatase functions in late G1 for progression into S phase.

Saccharomyces cerevisiae strains containing temperature-sensitive mutations in the SIT4 protein phosphatase arrest in late G1 at the nonpermissive temperature. Order-of-function analysis shows that SIT4 is required in late G1 for progression into S phase. While the levels of SIT4 do not change in the cell cycle, SIT4 associates with two high-molecular-weight phosphoproteins in a cell-cycle-dependent fashion. In addition, we have identified a polymorphic gene, SSD1, that in some versions can suppress the lethality due to a deletion of SIT4 and can also partially suppress the phenotypic defects due to a null mutation in BCY1. The SSD1 protein is implicated in G1 control and has a region of similarity to the dis3 protein of Schizosaccharomyces pombe. We have also identified a gene, PPH2alpha, that in high copy number can partially suppress the growth defect of sit4 strains. The PPH2 alpha gene encodes a predicted protein that is 80% identical to the catalytic domain of mammalian type 2A protein phosphatases but also has an acidic amino-terminal extension not present in other phosphatases.     

On technomorphic modelling and classification of biological joints

Summary Biological motion systems are of particular interest to engineers in robotics, prosthetics and micromechanics. Since biological motion systems show a high degree of mobility, smooth movements and minimal deployment of material, the analysis of such systems might help to invent or optimize technical motion systems. To enable the transfer of explanatory techniques, biomechanics and engineering need a shared terminology. Generally, a reference limb, muscles, tendons, a joint and a driven limb are forming two closed mechanisms with different transfer functions. The direction of the forces applied to links is influenced by guiding structures. Movable connections can be constructed by form closure, force closure, and compliance of an anisotropic segment between two rigid segments. Eleven different basic variants of rigid-body joint structures can be classified by the possible relative translatory and rotatory movements in orthogonal co-ordinates. If classified by the form of their rigid parts, biological rigid-body joints (diarthroses) show some similarities to technical joints, but occur in fewer basic variants. The functioning of exoskeletal joints can involve hydrostatic forces, depending on the structure of the rigid elements and the type of linkage between them. Structural classification of biological joints should include at least: 1) degree of freedom (d.o.f.), 2) possible relative movements, 3) variability of d.o.f., 4) restrictions of range of motion, 5) stress in reaction to external forces. From an engineer’s viewpoint, additional features are necessary for structural characterization, including the maintenance of closure and guidance, the geometry and behaviour of contact, geometrical parameters and material properties.     

Synthesis and characterization of the hexenuronic acid model methyl 4-deoxy-beta-L-threo-hex-4-enopyranosiduronic acid

A facile synthetic scheme for the preparation of methyl 4-deoxy-β-l-threo-hex-4-enopyranosiduronic acid utilizing the commercially available methyl α-d-galactopyranoside as starting material has been developed. The synthesis sequence comprises six high yielding reaction steps: TEMPO oxidation, acetylation, methanolysis of the lactone, acetylation, β-elimination, and final removal of the protecting groups. Only one column chromatographic purification is needed throughout the whole sequence. The overall yield is 60%. The final product has been characterized by NMR, Raman, UVRR, FTIR, and HRMS.     

Influence of selected Indian immunostimulant herbs against white spot syndrome virus (WSSV) infection in black tiger shrimp, Penaeus monodon with reference to haematological, biochemical and immunological changes

Immunostimulants are the substances, which enhance the non-specific defence mechanism and provide resistance against the invading pathogenic micro-organism. In order to increase the immunity of shrimps against the WSSV, the methanolic extracts of five different herbal medicinal plants like Cyanodon dactylon, Aegle marmelos, Tinospora cordifolia, Picrorhiza kurooa and Eclipta alba were selected and mixed thoroughly in equal proportion. The mixed extract was supplemented with various concentrations viz. 100 (A), 200 (B), 400 (C), and 800 (D) mgkg(-1) through artificial diets individually. The prepared diets (A-D) were fed individually to WSSV free healthy shrimp Penaeus monodon with an average weight of 8.0+/-0.5g for 25 days. Control diet (E), devoid of herbal extract was also fed to shrimps simultaneously. After 25 days of feeding experiment, the shrimps were challenged with WSSV, which were isolated and propagated from the infected crustaceans. The shrimps succumbed to death within 7 days when fed on no herbal immunostimulant diet (E). Among the different concentrations of herbal immunostimulant supplemented diets, the shrimps fed on diet D (800mgkg(-1)) significantly (P<0.0001) had more survival (74%) and reduction in the viral load. Also the better performance of haematological, biochemical and immunological parameters was found in the immunostimulant incorporated diets fed shrimps. The present work revealed that the application of herbal immunostimulants will be effective against shrimp viral pathogenesis and they can be recommended for shrimp culture.