Development of immune-biomarkers of pulmonary tuberculosis in a rabbit model

In silico agent-based modeling approach to characterize multiple in vitro tuberculosis infection models

In vitro models of Mycobacterium tuberculosis (Mtb) infection are a valuable tool for examining host-pathogen interactions and screening drugs. With the development of more complex in vitro models, there is a need for tools to help analyze and integrate data from these models. To this end, we introduce an agent-based model (ABM) representation of the interactions between immune cells and bacteria in an in vitro setting. This in silico model was used to simulate both traditional and spheroid cell culture models by changing the movement rules and initial spatial layout of the cells in accordance with the respective in vitro models. The traditional and spheroid simulations were calibrated to published experimental data in a paired manner, by using the same parameters in both simulations. Within the calibrated simulations, heterogeneous outputs are seen for bacterial count and T cell infiltration into the macrophage core of the spheroid. The simulations also predict that equivalent numbers of activated macrophages do not necessarily result in similar bacterial reductions; that host immune responses can control bacterial growth in both spheroid structure dependent and independent manners; that STAT1 activation is the limiting step in macrophage activation in spheroids; and that drug screening and macrophage activation studies could have different outcomes depending on the in vitro culture used. Future model iterations will be guided by the limitations of the current model, specifically which parts of the output space were harder to reach. This ABM can be used to represent more in vitro Mtb infection models due to its flexible structure, thereby accelerating in vitro discoveries.

Transcriptomic and Metabolomic Changes Reveal the Immunomodulatory Function of Casein Phosphopeptide-Selenium Chelate in Beagle Dogs

Casein phosphopeptide-selenium chelate (CPP-Se) is an organic compound produced by the chelation of casein phosphopeptide with selenium. This compound showed the ability to modulate canine immune response in our previous study; but its effect on the peripheral blood transcriptome and serum metabolome was unknown. This study aims to reveal the potential mechanism behind the immunomodulatory function of CPP-Se. We have identified 341 differentially expressed genes (DEGs) in CPP-Se groups as compared to the control group which comprised 110 up-regulated and 231 down-regulated genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis found that DEGs were mainly involved in immune-related signaling pathways. Moreover, the immune-related DEGs and hub genes were identified. Similarly, metabolomics identified 53 differentially expressed metabolites (DEMs) in the CPP-Se group, of which 17 were up-regulated and 36 were down-regulated. The pathways mainly enriched by DEMs were primary bile acid biosynthesis, tryptophan metabolism, and other amino acids metabolic pathways. Combined analysis of transcriptomic and metabolomic data showed that the DEGs and DEMs were commonly enriched in fatty acid biosynthesis, pyrimidine metabolism, glutathione metabolism, and glycerolipid metabolic pathways. Taken together, our findings provided a theoretical basis for further understanding of the immunomodulatory function of CPP-Se as well as a scientific reference for the future use of CPP-Se in pet foods as a dietary supplement to modulate the immunity.

Recent Developments in Mycobacteria-Based Live Attenuated Vaccine Candidates for Tuberculosis

Vaccination is an excellent approach to stimulating the host immune response and reducing human morbidity and mortality against microbial infections, such as tuberculosis (TB). Bacillus Calmette-Guerin (BCG) is the most widely administered vaccine in the world and the only vaccine approved by the World Health Organization (WHO) to protect against TB. Although BCG confers "protective" immunity in children against the progression of Mycobacterium tuberculosis (Mtb) infection into active TB, this vaccine is ineffective in protecting adults with active TB manifestations, such as multiple-, extensive-, and total-drug-resistant (MDR/XDR/TDR) cases and the co-existence of TB with immune-compromising health conditions, such as HIV infection or diabetes. Moreover, BCG can cause disease in individuals with HIV infection or other immune compromises. Due to these limitations of BCG, novel strategies are urgently needed to improve global TB control measures. Since live vaccines elicit a broader immune response and do not require an adjuvant, developing recombinant BCG (rBCG) vaccine candidates have received significant attention as a potential replacement for the currently approved BCG vaccine for TB prevention. In this report, we aim to present the latest findings and outstanding questions that we consider worth investigating regarding novel mycobacteria-based live attenuated TB vaccine candidates. We also specifically discuss the important features of two key animal models, mice and rabbits, that are relevant to TB vaccine testing. Our review emphasizes that the development of vaccines that block the reactivation of latent Mtb infection (LTBI) into active TB would have a significant impact in reducing the spread and transmission of Mtb. The results and ideas discussed here are only based on reports from the last five years to keep the focus on recent developments.

Immune response dynamics in COVID-19 patients to SARS-CoV-2 and other human coronaviruses

COVID-19 serological test must have high sensitivity as well as specificity to rule out cross-reactivity with common coronaviruses (HCoVs). We have developed a quantitative multiplex test, measuring antibodies against spike (S) proteins of SARS-CoV-2, SARS-CoV, MERS-CoV, and common human coronavirus strains (229E, NL63, OC43, HKU1), and nucleocapsid (N) protein of SARS-CoV viruses. Receptor binding domain of S protein of SARS-CoV-2 (S-RBD), and N protein, demonstrated sensitivity (94% and 92.5%, respectively) in COVID-19 patients (n = 53), with 98% specificity in non-COVID-19 respiratory-disease (n = 98), and healthy-controls (n = 129). Anti S-RBD and N antibodies appeared five to ten days post-onset of symptoms, peaking at approximately four weeks. The appearance of IgG and IgM coincided while IgG subtypes, IgG1 and IgG3 appeared soon after the total IgG; IgG2 and IgG4 remained undetectable. Several inflammatory cytokines/chemokines were found to be elevated in many COVID-19 patients (e.g., Eotaxin, Gro-α, CXCL-10 (IP-10), RANTES (CCL5), IL-2Rα, MCP-1, and SCGF-b); CXCL-10 was elevated in all. In contrast to antibody titers, levels of CXCL-10 decreased with the improvement in patient health suggesting it as a candidate for disease resolution. Importantly, anti-N antibodies appear before S-RBD and differentiate between vaccinated and infected people-current vaccines (and several in the pipeline) are S protein-based.

A Rabbit Model for Prolonged Continuous Intravenous Infusion Via a Peripherally Inserted Central Catheter

Medical treatment may require the continuous intravenous (IV) infusion of drugs to sustain the therapeutic blood concentration and to minimize dosing errors. Animal disease models that ultimately mimic the intended use of new potential drugs via a continuous IV infusion in unrestrained, free roaming animals are required. While peripherally inserted central catheters (PICCs) and other central line techniques for prolonged IV infusion of drugs are prevalent in the clinic, continuous IV infusion methods in an animal model are challenging and limited. In most cases, continuous IV infusion methods require surgical knowledge as well as expensive and complicated equipment. In the current work, we established a novel rabbit model for prolonged continuous IV infusion by inserting a PICC line from the marginal ear vein to the superior vena cava and connecting it to an externally carried ambulatory infusion pump. Either saline or a clinically relevant formulation could be steadily and continuously infused at 3–6 ml/h for 11 consecutive days into freely moving rabbits while maintaining normal body temperature, weight, and respiration physiology, as determined by daily spirometry. This new model is simple to execute and can advance the ability to administer and test new drug candidates.

The current state of animal models and genomic approaches towards identifying and validating molecular determinants of Mycobacterium tuberculosis infection and tuberculosis disease

Animal models are important in understanding both the pathogenesis of and immunity to tuberculosis (TB). Unfortunately, we are beginning to understand that no animal model perfectly recapitulates the human TB syndrome, which encompasses numerous different stages. Furthermore, Mycobacterium tuberculosis infection is a very heterogeneous event at both the levels of pathogenesis and immunity. This review seeks to establish the current understanding of TB pathogenesis and immunity, as validated in the animal models of TB in active use today. We especially focus on the use of modern genomic approaches in these models to determine the mechanism and the role of specific molecular pathways. Animal models have significantly enhanced our understanding of TB. Incorporation of contemporary technologies such as single cell transcriptomics, high-parameter flow cytometric immune profiling, proteomics, proteomic flow cytometry and immunocytometry into the animal models in use will further enhance our understanding of TB and facilitate the development of treatment and vaccination strategies.

Structures of soluble rabbit neprilysin complexed with phosphoramidon or thiorphan

Neutral endopeptidase (neprilysin; NEP) is a proteinase that cleaves a wide variety of peptides and has been implicated in Alzheimer's disease, cardiovascular conditions, arthritis and other inflammatory diseases. The structure of the soluble extracellular domain (residues 55-750) of rabbit neprilysin was solved both in its native form at 2.1 Å resolution, and bound to the inhibitors phosphoramidon and thiorphan at 2.8 and 3.0 Å resolution, respectively. Consistent with the extracellular domain of human neprilysin, the structure reveals a large central cavity which contains the active site and the location for inhibitor binding.

Potential biomarkers as an indicator of vertical transmission of Johne's disease in a Korean native cattle farm

Paratuberculosis (PTB) is caused by Mycobacterium avium subsp. paratuberculosis (MAP) and is one of the most widespread and economically important diseases in cattle. After birth, calves are raised with natural breast feeding without separation from their mothers in most Korean native cattle (Hanwoo breed) farms. Vertical transmission of PTB has been reported, but the exact PTB infection route has not been revealed in Hanwoo farms. Calves of MAP seropositive dams were tested for MAP presence and MAP antibodies in feces and tissues. MAP was detected in calf tissues by using polymerase chain reaction. Expressions of genes reported to be prognostic biomarkers of MAP infection changed in both calves and cows (p < 0.05). Expression of two genes (HGF and SERPINE1) were significantly decreased in MAP-infected cattle and their offspring (p < 0.01). The results suggest that biomarker gene expression profiles can be useful in detecting early stage MAP infection. Based on the results, complete eradication of MAP may be possible if accurate diagnostic methods to detect infected calves are added to the current PTB eradication strategy, which, because infected individuals are likely to develop into fecal MAP shedders at any time, includes isolation of new born calves and feeding sterilized colostrum.

Comparative transcriptomic analysis of porcine peripheral blood reveals differentially expressed genes from the cytokine-cytokine receptor interaction pathway related to health status

While some research has looked into the host genetic response in pigs challenged with specific viruses or bacteria, few studies have explored the expression changes of transcripts in the peripheral blood of sick pigs that may be infected with multiple pathogens on farms. In this study, the architecture of the peripheral blood transcriptome of 64 Duroc sired commercial pigs, including 18 healthy animals at entry to a growing facility (set as a control) and 23 pairs of samples from healthy and sick pen mates, was generated using RNA-Seq technology. In total, 246 differentially expressed genes were identified to be specific to the sick animals. Functional enrichment analysis for those genes revealed that the over-represented gene ontology terms for the biological processes category were exclusively immune activity related. The cytokine-cytokine receptor interaction pathway was significantly enriched. Nine functional genes from this pathway encoding members (as well as their receptors) of the interleukins, chemokines, tumor necrosis factors, colony stimulating factors, activins, and interferons exhibited significant transcriptional alteration in sick animals. Our results suggest a subset of novel marker genes that may be useful candidate genes in the evaluation and prediction of health status in pigs under commercial production conditions.

Establishment a real-time reverse transcription PCR based on host biomarkers for the detection of the subclinical cases of Mycobacterium avium subsp. paratuberculosis

Bovine paratuberculosis (PTB) is a chronic enteric inflammatory disease of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP) that causes large economic losses in the dairy industry. Spread of PTB is mainly provoked by a long subclinical stage during which MAP is shed into the environment with feces; accordingly, detection of subclinical animals is very important to its control. However, current diagnostic methods are not suitable for detection of subclinical animals. Therefore, the current study was conducted to develop a diagnostic method for analysis of the expression of genes of prognostic potential biomarker candidates in the whole blood of cattle naturally infected with MAP. Real-time PCR with nine potential biomarker candidates was developed for the diagnosis of MAP subclinical infection. Animals were divided into four groups based on fecal MAP PCR and serum ELISA. Eight genes (Timp1, Hp, Serpine1, Tfrc, Mmp9, Defb1, Defb10, and S100a8) were up-regulated in MAP-infected cattle (p <0.05). Moreover, ROC analysis revealed that eight genes (Timp1, Hp, Serpine1, Tfrc, Mmp9, Defb1, Defb10, and S100a8) showed fair diagnostic performance (AUC≥0.8). Four biomarkers (Timp1, S100a8, Defb1, and Defb10) showed the highest diagnostic accuracy in the PCR positive and ELISA negative group (PN group) and three biomarkers (Tfrc, Hp, and Serpine1) showed the highest diagnostic accuracy in the PCR negative and ELISA positive group (NP group). Moreover, three biomarkers (S100a8, Hp, and Defb10) were considered the most reliable for the PCR positive and ELISA positive group (PP group). Taken together, our data suggest that real-time PCR based on eight biomarkers (Timp1, Hp, Serpine1, Tfrc, Mmp9, Defb1, Defb10, and S100a8) might be useful for diagnosis of JD, including subclinical stage cases.