Respiratory mucosal immune system is the body''s first line of defense against infection.Since the outbreak of novel coronavirus disease 2019 (COVID-19) in 2019,nasal mucosal immune vaccine, with its ability to induce cellular, humoral and mucosal triple immune responses, has become a research hotspot.This article focuses on novel coronavirus, with an understanding of its structure and pathogenesis, a brief introduction to the immune mechanism of nasal mucosa, a summary of the different types of nasal mucosal immune vaccines and their clinical research, aiming to provide some theoretical reference for the development of new vaccines, and exploration of the best methods and strategies to combat COVID-19.

Objective: This study aimed to analyze the association between the characteristics of egocentric network and HIV prevalence among men who have sex with men (MSM) through social network analysis. Methods: The study was conducted in Guangzhou city from November 2016 to June 2017 using convenient sampling method. Participants were recruited from 13 voluntary counseling and testing (VCT) locations. Data were collected by using nomination generation and nomination interpretation methods. Questionnaire includes two parts, the first part about the social tie, and the second one about social demography and behavioral characteristics of respondents and their nominees. The multivariate logistic regression was applied to quantify the association. Results: 8.67%(93/1 073) HIV antibody positive MSM had been detected in 1 073 respondents who nominated 4 301 partners in total. Compared to egocentric sexual network with a size of 1-2, the size of sexual network larger than 3 (OR=1.68, 95%CI: 1.07-2.65) were associated with HIV infection. Compared to egocentric risk sexual network with a size of 1-2, the size of risk sexual networks larger than 3 (OR=1.87, 95%CI: 1.06-3.31) were associated with HIV infection. There were no significant association between marital similarity of respondents and their nominees, the type of the relationship of sexual partners and HIV prevalence (P>0.05). Conclusion The composition of social network in MSM is related to their susceptibility of HIV infection. MSM population with a large sexual network is more susceptible to HIV infection.

As a natural drug delivery carrier with rough and porous surface and hollow core， yeast microcapsules have good safety， high targeting and high stability， and have excellent application prospects in oral drug delivery systems. Yeast cells can be treated and washed with acid-base and organic solvents to obtain loose and porous yeast microcapsules. Yeast microcapsules can encapsulate drugs through electrostatic interactions， passive diffusion， hydrophobic interaction and other methods. The surface of yeast microcapsules is mainly composed of β-glucan， which can maintain stability in the gastrointestinal environment； it can be recognized by the surface-related receptors of immune cells， thus activating the immune response， and can be transported to the lesion site with the movement of lymphocytes after being ingested. Yeast microcapsules are safe and very suitable for delivering vaccines， anti-inflammatory drugs， and anti-tumor drugs. They can not only achieve oral delivery of the aforementioned drugs， but also enhance drug efficacy and improve drug targeting. In the future， more research on systemic transport mechanisms or the development of more efficient combination drug delivery systems can be carried out to fully exhibit the clinical value of yeast microcapsules.

Immunotherapy has revolutionized the landscape of cancer treatment. However, single immunotherapy only works well in a small subset of patients. Combined immunotherapy with antitumor synergism holds considerable potential to boost the therapeutic outcome. Nevertheless, the synergistic, additive or antagonistic antitumor effects of combined immunotherapies have been rarely explored. Herein, we established a novel combined cancer treatment modality by synergizing p21-activated kinase 4 (PAK4) silencing with immunogenic phototherapy in engineered extracellular vesicles (EVs) that were fabricated by coating M1 macrophage-derived EVs on the surface of the nano-complex cores assembled with siRNA against PAK4 and a photoactivatable polyethyleneimine. The engineered EVs induced potent PAK4 silencing and robust immunogenic phototherapy, thus contributing to effective antitumor effects in vitro and in vivo. Moreover, the antitumor synergism of the combined treatment was quantitatively determined by the CompuSyn method. The combination index (CI) and isobologram results confirmed that there was an antitumor synergism for the combined treatment. Furthermore, the dose reduction index (DRI) showed favorable dose reduction, revealing lower toxicity and higher biocompatibility of the engineered EVs. Collectively, the study presents a synergistically potentiated cancer treatment modality by combining PAK4 silencing with immunogenic phototherapy in engineered EVs, which is promising for boosting the therapeutic outcome of cancer immunotherapy.