Tetanus neurotoxin (TeNT) produced by Clostridium tetani is one of the most poisonous protein substances. Neutralizing antibodies against TeNT can effectively prevent and cure toxicosis. Using purified Hc fragments of TeNT (TeNT-Hc) as an antigen, three specific neutralizing antibody clones recognizing different epitopes were selected from a human immune scFv antibody phage display library. The three antibodies (2-7G, 2-2D, and S-4-7H) can effectively inhibit the binding between TeNT-Hc and differentiated PC-12 cells in vitro. Moreover, 2-7G inhibited TeNT-Hc binding to the receptor via carbohydrate-binding sites of the W pocket while 2-2D and S-4-7H inhibited binding of the R pocket. Although no single mAb completely protected mice from the toxin, they could both prolong survival when challenged with 20 LD₅₀s (50% of the lethal dose) of TeNT. When used together, the mAbs completely neutralized 1000 LD₅₀s/mg Ab, indicating their high neutralizing potency in vivo. Antibodies recognizing different carbohydrate-binding pockets could have higher synergistic toxin neutralization activities than those that recognize the same pockets. These results could lead to further production of neutralizing antibody drugs against TeNT and indicate that using TeNT-Hc as an antigen for screening human antibodies for TeNT intoxication therapy from human immune antibody library was convenient and effective.

INTRODUCTION: Liver fibrosis results from chronic liver injury and inflammation, often leading to cirrhosis, liver failure, portal hypertension, and hepatocellular carcinoma. Progress has been made in understanding the molecular mechanisms underlying hepatic fibrosis; however, translating this knowledge into effective therapies for disease regression remains a challenge, with considerably few interventions having entered clinical validation. The roles of exosomes during fibrogenesis and their potential as a therapeutic approach for reversing fibrosis have gained significant interest. This study aimed to investigate the association between microRNAs (miRNAs) derived from serum exosomes and liver fibrosis and to evaluate the effect of serum exosomes on fibrogenesis and fibrosis reversal, while identifying the underlying mechanism. METHODS: Using serum samples collected from healthy adults and paired histologic patients with advanced fibrosis or cirrhosis, we extracted human serum exosomes by ultrahigh-speed centrifugation. Transcriptomic analysis was conducted to identify dysregulated exosome-derived miRNAs. Liver fibrosis–related molecules were determined by qRT-PCR, Western blot, Masson staining, and immunohistochemical staining. In addition, we analyzed the importance of serum exosome–derived miRNA expression levels in 42 patients with advanced fibrosis or cirrhosis. RESULTS: Exosome-derived miR-193a-5p and miR-381-3p were associated with fibrogenesis, as determined by transcriptomic screening. Compared with healthy control group, the high expression of serum exosome–derived miR-193a-5p and miR-381-3 in chronic hepatitis B (n = 42) was closely associated with advanced liver fibrosis and cirrhosis. In vitro , exosome-derived miRNA-193a-5p and miR-381-3p upregulated the expression of α-smooth muscle actin, collagen 1a1, and tissue inhibitors of metalloproteinase 1 in the human hepatic stellate cell line at both mRNA and protein levels. DISCUSSION: Serum exosome–derived miR-193a-5p and miR-381-3p regulated the adenosine 5'-monophosphate–activated protein kinase/transforming growth factor beta/Smad2/3 signaling pathway and promoted fibrogenesis.

It is difficult to diagnose ascites infection early in cirrhotic patients. The present study was to create and evaluate a new bioscore combined with PCT, sNFI and dCHC in the diagnosis of ascites infection in cirrhotic patients. Two hundred and fifty-nine consecutive patients were enrolled; of which 51 patients were culture-positive spontaneous bacterial peritonitis (culture-positive SBP) and 58 patients were culture-negative SBP. The efficacy of procalcitonin(PCT), c-reactive protein (CRP), white blood cell (WBC), mean fluorescence intensity of mature neutrophils(sNFI) and difference in hemoglobin concentration between newly formed and mature red blood cells(dCHC) for diagnosing ascites infection was examined. These parameters were used to create a scoring system. The scoring system was analyzed by logistic regression analysis to determine which parameters were statistically different between ascites infection and non-ascites infection patients. Receiver operating characteristic curve (ROC) was used to analyze the diagnostic ability of bioscore for ascites infection. In ROC analysis, the area under the curves (AUC) for PCT was 0.852 (95% CI 0.803–0.921, P < 0.001), dCHC 0.837 (95% CI 0.773–0.923, P < 0.001), CRP 0.669 (95% CI 0.610–0.732, P = 0.0624), sNFI 0.838 (95% CI 0.777–0.903, P < 0.001), and WBC 0.624 (95% CI 0.500–0.722, P = 0.0881). Multivariate analysis revealed PCT, dCHC and sNFI to be statistically significant. The combination of these three parameters in the bioscore had an AUC of 0.937 (95% CI 0.901–0.994, P < 0.001). A bioscore of ≥3.40 was considered to be statistically significant in making a positive diagnosis of ascites infection. In different groups of ascites infection, bioscore also shown a high diagnostic value of AUC was 0.947(95% CI 0.882–0.988, P < 0.001) and 0.929 (95% CI 0.869–0.974, P < 0.001) for culture-positive SBP and culture-negative SBP group respectively. The composite markers of combining PCT, dCHC and sNFI could be a valuable diagnostic score to early diagnose ascites infection in patients with cirrhosis.

Introduction Sierra Leone has one of the highest burdens of febrile illnesses in the world. As the incidence of malaria diminishes, a better understanding of the spectrum of etiological agents was important for accurate diagnosis and empirical treatment of febrile illness. Methods Blood, nasopharyngeal, and fecal specimens were collected from febrile patients for serological, molecular detection, and microbiologic culture to identify potential pathogens. Results For this prospective study, 142 febrile patients were enrolled. The prevalence of malaria was higher in children aged 5–15 years old (P = 0.185) and adults (P = 0.018). Acute respiratory infection (ARI) presented more commonly in the under 5 years old group (P = 0.009). For diarrhea, all children groups (P = 0.024) were predominant. A total of 22.5% of the febrile patients had malaria infection, 19.7% had typhoid infection, and 2.8% were coinfected with malaria and typhoid. ARI was the most common causes of fever, accounting for 31.7% of patients, influenza A virus, Mycoplasma pneumoniae, and five other respiratory pathogens were found. Diarrhea accounted for 16.2%, and seven kinds of diarrhea bacteria were isolated. Hepatitis B accounted for 8.5%, including five cases of spontaneous bacterial peritonitis, and ascites smear staining were both Gram-negative bacteria. Tuberculous encephalitis, parasitic diseases (ascaris and filariasis), and skin infection caused by Staphylococcus aureus accounted for 0.7%, 2.1%, and 0.7%, respectively. Conclusions Evidence of a wide spectrum of febrile etiological agents other than malaria was identified. The spread of malaria rapid diagnostic tests (RDTs) out of hospital and establishment of a national standard for Widal test will reduce the misdiagnosis of febrile diseases. Antibiotics against Gram-negative bacteria are helpful for empirical treatment.

Dongke Chen, M.A., Han Wang, M.D., Xianlei Lu, M.A., Yao Cui, M.A., Xiaohan Ma, M.A., Jing Lou, M.M. and Haijian Zhou, M.M.. Ann Lab Med 2021;41:439-42. https://doi.org/10.3343/alm.2021.41.4.439