The effect of O-antigen length determinant wzz on the immunogenicity of Salmonella Typhimurium for Escherichia coli O2 O-polysaccharides delivery.

Attenuated Salmonella Typhimurium is a promising antigen delivery system for live vaccines such as polysaccharides. The length of polysaccharides is a well-known key factor in modulating the immune response induced by glycoconjugates. However, the relationship between the length of Lipopolysaccharide (LPS) O-antigen (OAg) and the immunogenicity of S. Typhimurium remains unclear. In this study, we assessed the effect of OAg length determined by wzzST on Salmonella colonization, cell membrane permeability, antimicrobial activity, and immunogenicity by comparing the S. Typhimurium wild-type ATCC14028 strain to those with various OAg lengths of the ΔwzzST mutant and ΔwzzST::wzzECO2. The analysis of the OAg length distribution revealed that, except for the very long OAg, the short OAg length of 2-7 repeat units (RUs) was obtained from the ΔwzzST mutant, the intermediate OAg length of 13-21 RUs was gained from ΔwzzST::wzzECO2, and the long OAg length of over 20 RUs was gained from the wild-type. In addition, we found that the OAg length affected Salmonella colonization, cell permeability, and antibiotic resistance. Immunization of mice revealed that shortening the OAg length by altering wzzST had an effect on serum bactericidal ability, complement deposition, and humoral immune response. S. Typhimurium mutant strain ΔwzzST::wzzECO2 possessed good immunogenicity and was the optimum option for delivering E. coli O2 O-polysaccharides. Furthermore, the attenuated strain ATCC14028 ΔasdΔcrpΔcyaΔrfbPΔwzzST::wzzECO2-delivered E. coli O2 OAg gene cluster outperforms the ATCC14028 ΔasdΔcrpΔcyaΔrfbP in terms of IgG eliciting, cytokine expression, and immune protection in chickens. This study sheds light on the role of OAg length in Salmonella characteristics, which may have a potential application in optimizing the efficacy of delivered polysaccharide vaccines.

Ultrasound Elastography supplement assessing nodal status of magnetic resonance imaging staged cervical N0 patients with nasopharyngeal carcinoma.

BACKGROUND: To determine whether ultrasound elastography can distinguish reactive or metastatic small lymph nodes (sLN) of magnetic resonance imaging (MRI) staged cervical N0 patients with nasopharyngeal carcinoma (NPC). METHODS: A pilot study was performed involving the diagnostic performances of conventional high-frequency ultrasound (CHFU) and/or shear wave elastography (SWE) for predicting metastases in sLN of MRI-staged N0 NPC patients with reference to the histologically-proven ultrasound guided core needle biopsy (US-CNB). The diagnosis of CHFU was based on the superficial lymph node ultrasonic criteria with the five-point-scale (FPS). The mean (Emean), minimum (Emin) and maximum (Emax) of the elasticity indices were measured by SWE at the stiffest part of the sLN in kilopascal. Diagnostic performances were analyzed using a receiver operating curve (ROC) on a per-node basis. The authenticity of this article has been validated by uploading the key raw data onto the Research Data Deposit public platform ( http://www.researchdata.org.cn ), with the approval RDD number as RDDA2017000447. RESULTS: All 113 cervical sLN of 49 MRI-staged cervical N0 NPC patients underwent evaluation of CHFU and SWE; 38 sLN (FPS < 2) were regarded as benign, which were excluded from subsequent analysis due to none biopsy-proven. And 75 indeterminate sLN (FPS ≥ 2) were referred to US-CNB and revealed 15 (20%) metastases. All SWE elastic indices were significantly higher in malignant sLNs than in benign sLNs (p < 0.05). Moreover, Emax exhibited the highest diagnostic value (AUC:0.733 ± 0.067, p = 0.005) with excellent measurement reproducibility (ICC: 0.786; 95%CI: 0.684, 0.864). CHFU plus SWE was superior to CHFU or SWE alone for predicting metastases in sLN of MRI-staged N0 patients with NPC (p < 0.001). CONCLUSIONS: CHFU plus SWE is an optional non-invasive modality to supplement MRI in assessing cervical nodal status of patients with NPC.

Retraction Note to: Ultrasound Elastography supplement assessing nodal status of magnetic resonance imaging staged cervical N0 patients with nasopharyngeal carcinoma.

The Editors have retracted this article [1] because figure 2 has been substantially duplicated from a previously published article by Chen B et al., 2018 [2]. There is also significant and uncited overlap in the patient population between the two articles resulting in concerns relating to the scientific validity and novelty of the data.