Multi-omics analysis reveals that linoleic acid metabolism is associated with variations of trained immunity induced by distinct BCG strains.

Trained immunity is one of the mechanisms by which BCG vaccination confers persistent nonspecific protection against diverse diseases. Genomic differences between the different BCG vaccine strains that are in global use could result in variable protection against tuberculosis and therapeutic effects on bladder cancer. In this study, we found that four representative BCG strains (BCG-Russia, BCG-Sweden, BCG-China, and BCG-Pasteur) covering all four genetic clusters differed in their ability to induce trained immunity and nonspecific protection. The trained immunity induced by BCG was associated with the Akt-mTOR-HIF1α axis, glycolysis, and NOD-like receptor signaling pathway. Multi-omics analysis (epigenomics, transcriptomics, and metabolomics) showed that linoleic acid metabolism was correlated with the trained immunity-inducing capacity of different BCG strains. Linoleic acid participated in the induction of trained immunity and could act as adjuvants to enhance BCG-induced trained immunity, revealing a trained immunity-inducing signaling pathway that could be used in the adjuvant development.

Trained immunity: A Yin-Yang balance.

Traditionally, immune memory is regarded as an exclusive hallmark of adaptive immunity. However, a growing body of evidence suggesting that innate immune cells show adaptive characteristics has challenged this dogma. In the past decade, trained immunity, a de facto innate immune memory, has been defined as a long-term functional reprogramming of cells of the innate immune system: the reprogramming is evoked by endogenous or exogenous insults, the cells return to a nonactivated state and subsequently show altered inflammatory responses against a second challenge. Trained immunity became regarded as a mechanism selected in evolution to protect against infection; however, a maladaptive effect might result in hyperinflammation. This dual effect is consistent with the Yin-Yang theory in traditional Chinese philosophy, in which Yang represents active, positive, and aggressive factors, whereas Yin represents passive, negative, and inhibitory factors. In this review, we give a brief overview of history and latest progress about trained immunity, including experimental models, inductors, molecular mechanisms, clinical application and so on. Moreover, this is the first time to put forward the theory of Yin-Yang balance to understand trained immunity. We envision that more efforts will be focused on developing novel immunotherapies targeting trained immunity in the coming years.

Molecular cloning, identification and functional characterization of a novel intracellular Cu-Zn superoxide dismutase from the freshwater mussel Cristaria plicata.

Superoxide dismutases (SODs, EC 1.15.1.1) are one family of important antioxidant metalloenzymes involved in scavenging the high level of reactive oxygen species (ROS) into molecular oxygen and hydrogen peroxide. In the present study, the intracellular CuZnSOD gene of Cristaria plicata (Cp-icCuZnSOD) was identified from hemocytes by homology cloning and the rapid amplification of cDNA ends (RACE) technique. The full-length cDNA of Cp-icCuZnSOD consisted of 891 nucleotides with a canonical polyadenylation signal sequence ATTAAA, a poly (A) tail, and an open-reading frame of 468 bp encoding 155 amino acids. The deduced amino acids of CpSOD shared high similarity with the known icCuZnSODs from other species, and several highly conserved motifs including Cu/Zn ions binding sites (His-46, His-48, His-63, His-120 for Cu(2+) binding, and His-63, His-71, His-80, Asp-83 for Zn(2+) binding), intracellular disulfide bond and two CuZnSOD family signatures were also identified in CpSOD. Furthermore, the recombinant Cp-icCuZnSOD with high enzyme activity was induced to be expressed as a soluble form by IPTG supplemented with Cu/Zn ions at 20 degrees C for 8 h, and then was purified by using the native Ni(2+) affinity chromatography. The specific activity of the purified rCp-icCuZnSOD enzyme was 5368 U/mg, which is 2.6-fold higher than that of zebrafish Danio rerio rZSOD and 5.3-fold higher than that of bay scallop Argopecten irradians rAi-icCuZnSOD. The enzyme stability assay showed that the purified rCp-icCuZnSOD enzyme maintained more than 80% activity at temperature up to 60 degrees C, at pH 2.0-9.0, and was resistant to 8 mol/L urea or 8% SDS. In addition, the addition of active rCp-icCuZnSOD enzmye could protect hepatocyte L02 cells from oxidative damage as assessed using an alcohol-injured human liver cell model.

Evaluation of vaccines in the EU TB Vaccine Cluster using a guinea pig aerosol infection model of tuberculosis.

The TB Vaccine Cluster project funded by the EU Fifth Framework programme aims to provide novel vaccines against tuberculosis that are suitable for evaluation in humans. This paper describes the studies of the protective efficacy of vaccines in a guinea pig aerosol-infection model of primary tuberculosis. The objective was to conduct comparative evaluations of vaccines that had previously demonstrated efficacy in other animal models. Groups of 6 guinea pigs were immunized with vaccines provided by the relevant EU Vaccine Cluster partners. Survival over 17 or 26 weeks was used as the principal measure of vaccine efficacy following aerosol challenge with H37Rv. Counts of mycobacteria in lungs and spleens, and histopathological changes in the lungs, were also used to provide evidence of protection. A total of 24 vaccines were evaluated in 4 experiments each of a different design. A heterologous prime-boost strategy of DNA and MVA, each expressing Ag85A and a fusion protein of ESAT-6 and Ag85B in adjuvant, protected the guinea pigs to the same extent as BCG. Genetically modified BCG vaccines and boosted BCG strategies also protected guinea pigs to the same extent as BCG but not statistically significantly better. A relatively high aerosol-challenge dose and evaluation over a protracted time post-challenge allowed superior protection over BCG to be demonstrated by BCG boosted with MVA and fowl pox vectors expressing Ag85A.