[Extraction, Characterization and Immune Effect Analysis of Listeria Monocytogenes Membrane Vesicles].

OBJECTIVE: To establish a method for extracting Listeria monocytogenesmembrane vesicles (LM-MVs) and to analyze the characteristics of LM-MVs and their ability to induce innate immune effect in vitro so as to lay the foundation for research into using LM-MVs as vaccine carrier and drug delivery platform. METHODS: The membrane vesicles secreted by Listeria monocytogenes were extracted through a continuous process, including culturing, centrifugation, filtration, ultrafiltration concentration and ultracentrifugation. The morphological characteristics of LM-MVs were observed with transmission electron microscope, and particle size distribution were measured by dynamic light scattering analysis. SDS-PAGE and Western blot were used to analyze the protein composition of LM-MVs. CCK-8 cell proliferation and toxicity determination experiments were done to analyze their effect on the proliferation of innate immune cells, and qPCR was used to analyze their ability to induce innate immune responses. RESULTS: A method for extracting LM-MVs was successfully established. Under the transmission electron microscope, LM-MVs presented a nearly circular film-like structure, and dynamic light scattering analysis showed that their sizes were between 65 and 190 nm. SDS-PAGE and Western blot showed that LM-MVs contained proteins, including listeriolysin O (LLO). CCK-8 cell proliferation and toxicity experiment showed that after intervention with 10, 20 and 50 µg/mL of LM-MVs for 24 hours, the proliferation rate of DC 2.4 mouse dendritic cell line was higher than that of non-interventional DC 2.4 cells ( P<0.05); after intervention with 0.1, 1, 10, 20 and 50 µg/mL of LM-MVs for 24 hours, the proliferation rate of RAW 264.7 cells was higher than that of non-interventional RAW 264.7 cells ( P<0.01). The results of qPCR showed that, after intervention with 50 µg/mL of LM-MVs, the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6 and IL-10 in RAW 264.7 cells were higher than those of non-intervention control cells ( P<0.05). CONCLUSIONS: The method established in the study can be used to extract LM-MVs. The extracted LM-MVs have a diameter of 65-190 nm and a nearly circular membrane-like structure. They can secrete a variety of protein components and stimulate innate immune responses.

Survival outcomes in patients with parotid gland carcinoma treated with postoperative therapies using risk stratification.

BACKGROUND: To evaluate the role of postoperative treatment in parotid gland carcinoma (PGC) based on risk stratification. MATERIAL AND METHODS: A total of 301 PGC patients were retrospectively analyzed using risk stratification. The Kaplan-Meier method and Cox analysis were performed to conduct survival analysis. RESULTS: In the high-risk group, those treated with postoperative radiotherapy (RT) had a better 5-year disease-free survival (DFS) than those treated with surgery alone. In the low-risk group, both surgery + RT and surgery + chemotherapy (CT) significantly improved DFS when compared with surgery alone. Cox analysis showed that patients who underwent surgery + RT or surgery + CT had a lower risk of disease progression than those who underwent surgery alone in the low-risk group. In the high-risk group, patients who underwent surgery + RT had a lower risk of disease progression. CONCLUSIONS: Postoperative RT showed considerable benefit in improving disease control in patients with PGC, even in those without high-risk factors.

Clinical and survival analysis of nasopharyngeal carcinoma with consistently negative Epstein-Barr virus DNA.

BACKGROUND: To assess the clinical and survival features of nasopharyngeal carcinoma (NPC) with consistently negative Epstein-Barr virus (EBV) DNA level. METHODS: Propensity score matching (PSM) method was used to create well-balanced cohorts. Kaplan-Meier method and Cox proportional hazards models were performed to conduct survival analysis. RESULTS: Four hundred and eighty patients were enrolled. Patients with consistently negative plasma EBV DNA level had a greater chance to present a relatively earlier T and N classification compared with those with positive EBV DNA level (p < .001; p = .015). And patients with consistently negative EBV level were significantly associated with preferable 3-year DFS (95.0% vs. 84.4%, p = .004), DMFS (98.3% vs. 89.4%, p = .009), and OS (100% vs. 97.6%, p = .004). CONCLUSIONS: NPC patients with consistently negative EBV DNA level performed an earlier clinical stage and negative EBV DNA level was related to preferable survival outcomes.