诺如病毒实验室诊断现状与展望

诺如病毒是引起非细菌性急性胃肠炎的主要病因,常常引起严重的公共卫生与食品安全问题。诺如病毒基因组的多样性及其它们不断的进化和变异为临床诊断及疫苗研制带来了挑战。本文就诺如病毒实验室诊断方法的研究进展作一综述,包括从传统经典的核酸检测到应用纳米、芯片等高新技术的多重核酸定量检测和高通量测序平台,以及体外成功培养的报道等等。这些新技术的成功运用将推动诺如病毒实验室诊断的新发展,以满足临床诊疗及疫苗研制的新需求。

In vitro incubation of cytokine-induced killer cells from patients with and without hepatitis B virus and a cell subset analysis

Objective The aim of the study was to explore the difference between immune cell subsets during the incubation of cytokine-induced kill cells （CIKs） from patients with and without hepatitis B virus （HBV）. Methods Peripheral blood samples were extracted from 50 tumor patients, and were divided into two groups according to the presence or absence of HBV. The proliferation rate and activity of CIK cells were examined based on counts on days 1, 5, 7, 9, 11, 13, and 15 of culture. Additionally, the CD3＋, CD4＋, CD8＋, CD3＋CD8＋, C＋）3＋CD4＋, and CD3＋CD56＋ T cell populations were analyzed by flow cytometry on days 5, 7, 10, 13, and 15 of culture. Results Proliferation over a 15-day period was higher in the HBV-positive group than in the negative group （280-fold vs. 180-fold increase, respectively）, but there was no significant difference between the two groups at each time point. The frequencies of CD3＋, CD8＋ T, CD3＋CD8＋, and CD3＋CD56＋T cells increased over time, while those of CD4＋ and CD3＋CD4＋ T cells decreased over time, and these changes were greater in the positive group than in the negative group. The differences in CD8＋ T cells and CD3＋CD4＋ T cells between the two groups were significant （P 〈 0.05）. Conclusion The proliferative capacity of CIK cells was higher for patients in the HBV-positive group than those in the HBV-negative group, and immune cell subsets were more favorable in the HBV-positive group than the neaative arouD.

Cryo-EM structures of infectious bursal disease viruses with different virulences provide insights into their assembly and invasion

Infectious bursal disease virus(IBDV)causes a highly contagious immunosuppressive disease in chickens,resulting in significant economic losses.The very virulent IBDV strain(vvIBDV)causes high mortality and cannot adapt to cell culture.In contrast,attenuated strains of IBDV are nonpathogenic to chickens and can replicate in cell culture.Although the crystal structure of T=1 subviral particles(SVP)has been reported,the structures of intact IBDV virions with different virulences remain elusive.Here,we determined the cryo-electron microscopy(cryo-EM)structures of the vvIBDV Gx strain and its attenuated IBDV strain Gt at resolutions of 3.3 Å and 3.2 Å,respectively.Compared with the structure of T=1 SVP,IBDV contains several conserved structural elements unique to the T=13 virion.Notably,the Nterminus of VP2,which is disordered in the SVP,interacts with the S_(F) strand of VP2 from its neighboring trimer,completing theβ-sheet of the S domain.This interaction helps to form a contact network by tethering the adjacent VP2 trimers and contributes to the assembly and stability of the IBDV virion.Structural comparison of the Gx and Gt strains indicates that H253 and T284 in the VP2 P domain of Gt,in contrast to Gx,form a hydrogen bond with a positively charged surface.This suggests that the combined mutations Q253 H/A284 T and the associated structural electrostatic features of the attenuated Gt strain may contribute to adaptation to cell culture.Furthermore,a negatively charged groove in VP2,containing an integrin binding IDA motif that is critical for virus attachment,was speculated to play a functional role in the entry of IBDV.