T-cell mediated responses against alpha-foetoprotein in hepatocellular carcinoma: Relationship with hepatitis C virus infection, tumour phenotype and patients’ survival

Background Alpha-foetoprotein (AFP) is a potential immunotherapeutic target in hepatocellular carcinoma (HCC). However, T-cell response (TR) to AFP is suppressed in HCC due to immune evasion. It is unknown whether HCV infection may pre-condition TR against AFP, or whether TR may influence the clinical course of HCC. Methods We prospectively enrolled 18 HCV+ treatment-naïve patients with cirrhosis (CC), 18 HCV+ HCC cases and 17 HCV- HCC cases. TR was quantified by ELISPOT using assays specific to interleukin (IL) 2, IL10 and granulocyte-monocyte colony stimulating factor (GM-CSF) on ex-vivo peripheral blood mononuclear cells (PBMC) stimulated in vitro with AFP peptides. Cytokine ratios were compared between groups and with clinicopathological features of HCC, including overall survival (OS). Results The proportion of AFP-specific responses was not different across the studied groups for any of the assayed cytokines. AFP-specific IL-2 responses were increased in larger (P = .02), multifocal tumours (P = .01) and correlated with advanced disease (P = .01). TRs did not correlate with other clinicopathological factors and did not predict for OS. Conclusion Tumour stage but not HCV infection is related to the emergence of anti-AFP TRs. These data enable formulation of a rationale for the further development of anti-AFP immunotherapy in HCC, facilitating optimal patient selection for future studies

c-di-GMP Turn-Over in Clostridium difficile Is Controlled by a Plethora of Diguanylate Cyclases and Phosphodiesterases

Clostridium difficile infections have become a major healthcare concern in the last decade during which the emergence of new strains has underscored this bacterium's capacity to cause persistent epidemics. c-di-GMP is a bacterial second messenger regulating diverse bacterial phenotypes, notably motility and biofilm formation, in proteobacteria such as Vibrio cholerae, Pseudomonas aeruginosa, and Salmonella. c-di-GMP is synthesized by diguanylate cyclases (DGCs) that contain a conserved GGDEF domain. It is degraded by phosphodiesterases (PDEs) that contain either an EAL or an HD-GYP conserved domain. Very little is known about the role of c-di-GMP in the regulation of phenotypes of Gram-positive or fastidious bacteria. Herein, we exposed the main components of c-di-GMP signalling in 20 genomes of C. difficile, revealed their prevalence, and predicted their enzymatic activity. Ectopic expression of 31 of these conserved genes was carried out in V. cholerae to evaluate their effect on motility and biofilm formation, two well-characterized phenotype alterations associated with intracellular c-di-GMP variation in this bacterium. Most of the predicted DGCs and PDEs were found to be active in the V. cholerae model. Expression of truncated versions of CD0522, a protein with two GGDEF domains and one EAL domain, suggests that it can act alternatively as a DGC or a PDE. The activity of one purified DGC (CD1420) and one purified PDE (CD0757) was confirmed by in vitro enzymatic assays. GTP was shown to be important for the PDE activity of CD0757. Our results indicate that, in contrast to most Gram-positive bacteria including its closest relatives, C. difficile encodes a large assortment of functional DGCs and PDEs, revealing that c-di-GMP signalling is an important and well-conserved signal transduction system in this human pathogen

Collagen structure: Evidence for a helical organization of the collagen fibril

The collagen fibrils of human or guinea pig dermis when exposed to the denaturing agents, urea or guanidine--HCl, dissociated into smaller, disparate subunits, probably aggregates of microfibrils. The process of dissociation demonstrates that the fibrils are assembled helically. Initially, diagonal clefts appear on the surface of the fibril. These clefts are surface manifestations of a spirally oriented, internal space. Continued exposure to these denaturants resulted in progressive dissociation of the fibril into helically oriented subunits. It is suggested that water-miscible compounds such as glycols or hydroxypropyl methacrylate, in addition to the urea--guanidinium class of denaturants used in this study, affect the observed fbrillar changes through the disruption of hydrogen bonds between the microfibrils making up the fibril. Such a mode of action may explain why freeze-fractured or "inert embedded" collagen demonstrates helical organization while other, more conventional methods of tissue processing do not. Further support for the proposed mode of action of these dissociative agents was provided by the observation that mature collagen, in which extensive intra- and intermolecular covalent crosslinks are present, is more resistant to dissociation than newly formed collagen.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22986/1/0000554.pd