2019年 · 第01卷第03期

In this article we summarize the development of vehicles for penetrating living cells, tissue and organisms with nucleic acids (DNA and RNA) and proteins that damage or repair DNA. The purpose in doing so is to provide an assessment of the potential for these technologies to unintentionally cause harm to human health or the environment or to be re-tasked with an intention to cause harm. Two new types of biological-molecule-based products are being developed for use in medicine, agriculture and food production or preservation. The first type are genetically modified organisms, such as those that express bio-pesticides. They produce molecules and that are difficult to alter at scale after release. Products of this type are usually evaluated by both food and environmental regulators. The second type comprises topical chemical or physical agents. Most of these are in pre-commercial testing phase. Topically applied products use nucleic acids and/or proteins wherein the active biological is transferred by contact, ingestion or inhalation. From a survey of the research and patent literature we suggest that chemical formulations and physical manipulations that can be used to ferry nucleic acid and protein cargo into cells, tissues or organisms could be assembled de novo or repurposed from existing commercial products and loaded with proteins and/or nucleic acids designed using publicly available genome sequences. Biological actives may evade risk assessment and regulatory review because they are often excluded from the category of hazardous chemicals and are actively being excluded as agents of genetic modification. This emerging gap in oversight could lead to either dual use appropriation or unintended harm to human health or the environment.

Promoting biosafety regulations and techniques supports human health and protects individuals and groups from harmful incidents. Particular attention should be paid to those potential infectious hazards associated with blood and other bodily fluids, especially those highly transmitted infectious diseases, such as human immunodeficiency virus (HIV), one of the largest global health threats. Ensuring innovative and adaptive screening and laboratory techniques to reduce the possibility of HIV transmission are integral to managing the disease. We review here the evolution and success of blood screening techniques for HIV, along with current issues that still need to be addressed. Published academic articles and media reports about nosocomial HIV transmission events since 1981 were reviewed to identify current blood screening and transfusion safety trends across the globe, along with specific recommendations from the Chinese perspective. Although most initial screening was limited only to antibody and antigen testing, newer screening tests (such as nucleic acid testing), coupled with risk-based screening of donors, have led to reduced risk of HIV transmission and continues to reduce the "window period," when an HIV-positive individual may test negative though they have been infected. Further examination of current guidelines and regulations across the globe are discussed, in order to understand where critical gaps in screening may exist. Through examination of this data, it is evident that huge strides have been made since the beginning of the epidemic; however improved technical training of staff and streamlined testing guidelines could help promote efficient screening of HIV, while also supporting those providing care.

A significant number of biosafety level 2 (BSL-2) laboratories have been established in many countries for studies of various types of pathogenic agents and other infectious biological materials. The harmonized management of biological risks in such diverse laboratories thus appears as a real challenge. Zhejiang Province in China has taken the initiative to establish a comprehensively integrated laboratory biosafety management system called SINS (Standardization, Informatization, Normalization and Systematization). The SINS model system has been introduced and adopted in 1,721 BSL-2 laboratories in Zhejiang Province, and thus lead to an increase in the number of biosafety committees from 20% to more than 95% from 2007 to 2018, and the number of biosafety laboratory managers who knows biosafety-related laws and regulations increase from 52.7% to 83.7% from 2009 to 2017. Such achievements indicate that the successful implementation of SINS model has increased the effective control of biological risks in BSL-2 laboratories of the Zhejiang Province. SINS model and its main effects on leading the improvement of laboratory biosafety management was presented in this review. The SINS model helps to strengthen laboratory biosafety and thus effectively reduces occurrence of biosafety-related incidences. This model can potentially be used by other regions or countries where harmonized biosafety management system is still under-developing.

The Middle East respiratory syndrome (MERS) is a lethal zoonosis caused by MERS coronavirus (MERS-CoV) and poses a significant threat to public health worldwide. Therefore, a rapid, sensitive, and specific serologic test for detecting anti-MERS-CoV antibodies in both humans and animals is urgently needed for the successful management of this illness. Here, we evaluated various novel luciferase immunosorbent assays (LISA) based on nucleocapsid protein (NP) as well as fragments derived from spike protein (S) including subunit 1 (S1), N terminal domain (NTD), receptor-binding domain (RBD) and subunit 2 (S2) of S for the detection of MERS-CoV-specific IgG. Fusion proteins, including nanoluciferase (NLuc) and various fragments derived from the NP or S protein of MERS-CoV, were expressed in human embryonic kidney 293 T cells. LISAs that detected anti-MERS-CoV IgG were further developed using cell lysates expressing various fusion proteins. Panels of human or animal samples infected with MERS-CoV were used to analyze the sensitivity and specificity of various LISAs in reference to a MERS-CoV RT-PCR, commercial S1-based ELISA, and pseudovirus particle neutralization test (ppNT). Our results showed that the S1-, RBD-, and NP-LISAs were more sensitive than the NTD- and S2-LISAs for the detection of anti-MERS-CoV IgG. Furthermore, the S1-, RBD-, and NP-LISAs were more sensitive (by at least 16-fold) than the commercially available S1-ELISA. Moreover, the S1-, RBD-, and NP-LISA specifically recognized anti-MERS-CoV IgG and did not cross-react with samples derived from other human CoV (OC43, 229E, HKU1, NL63)-infected patients. More importantly, these LISAs proved their applicability and reliability for detecting anti-MERS-CoV IgG in samples from camels, monkeys, and mice, among which the RBD-LISA exhibited excellent performance. The results of this study suggest that the novel MERS-CoV RBD- and S1-LISAs are highly effective platforms for the rapid and sensitive detection of anti-MERS-CoV IgG in human and animal samples. These assays have the potential to be used as serologic tests for the management and control of MERS-CoV infection.

The frequent and sudden occurrence of both known and unknown infectious diseases can cause global social panic. If the source of infection can be effectively controlled in the early stages of an outbreak, the spread of infectious diseases can be prevented. In view of this situation, this study developed for infectious or suspected infectious patients a negative pressure isolation hood which effectively achieves direct individual isolation during the early stages of disease outbreak, and facilitates long-distance transport. The hood body is made of flexible transparent polyvinyl chloride (PVC) material, and the combination of the hood material is airtight. The unique inflatable column support structure and the design of the inflatable neck sleeve effectively ensure both stiffness and air tightness of the hood body. The electrical exhaust system maintains a stable negative pressure environment inside the hood, and polluted air inside the hood can be purified by a high efficiency filter. Test results showed that the internal noise of the hood was 68 ± 1 dB (A), the air exhaust volume of the electric exhaust system was not <200 L/min, and the filtration efficiency of the filter to 0.3 μm particles was >99.99%, indicating that the hood achieved effective isolation protection for patients with respiration infectious diseases.

Here, we report the identification of Histoplasma causing an unexplained disease cluster in Matthews Ridge, Guyana. In March 2019, 14 employees of Chongqing Bosai Mining Company, China, working in a manganese mining of Guyana, had unexplained fever, and two of them died. We obtained lung and brain tissues as well as the blood samples from the two deceased cases (patient No. 1 and 2), and bronchoscopy lavages and cerebrospinal fluid samples from one severe case (patient No. 3), respectively. All samples were tested by pathological examination, high-throughput sequencing, and real-time PCR. Pathological detection showed the presence of spore-like structures in the lung tissue of patient No. 1, indicating a fungal infection in this patient. Nanopore sequencing identified the existing of H. capsulatum in the lung tissue sample within 13 h. Next-generation sequencing identified specific fragments of H. capsulatum in all of the samples tested (lung, brain and blood serum from the deceased cases, and plasma from the severe case). Real-time PCR assays did not reveal any viral infection related to transmission from bat feces. We conclude that H. capsulatum was the causative pathogen of this disease cluster based on epidemiologic, clinical, pathological and nucleic acid evidence.

A nation-wide case surveillance was conducted in China since 1995 for the objective of identifying acute flaccid paralysis (AFP) in children so that potential wild polioviruses and vaccine-derived poliovirus (VDPV) could be identified on time. Two outbreaks associated with type I circulating VDPVs, eight native independent type I ambiguous VDPVs (aVDPV), and one imported aVDPV were identified during the AFP case surveillance in China from 1995 to 2019. The VP1 coding region of the Chinese type I VDPVs differed from the polio vaccine strain by 1.00%–3.75% (9–34 substitutions in 906 nucleotides). Most of the Chinese type I VDPV strains shared 4 amino acid substitutions in the neutralizing antigenic (NAg) sites: 3 located at the BC loop, which formed the NAg site 1, and another at NAg site 3a. All of the Chinese type I VDPVs identified during the AFP case surveillance were young VDPVs, which indicated a limited viral replication resulted from the administration of the initiating oral polio vaccine (OPV) dose. VDPVs can emerge and spread in isolated communities with immunity gaps and the circulation ceases following a mass immunization with OPV. As such, high-quality surveillance permitted very early detection and response and it played a key role in stalling the widespread circulation of the emergent cVDPV strains in China.

Antibodies are ideal for controlling the influenza A virus, but their effect on newly emerging strains is unclear. Here, we assessed the neutralization activity of the humanized monoclonal antibodies (mAbs) F10, H98 and H40 against circulating influenza viruses (H5N1, H1N1, H3N2 and H7N7 and new subtypes viruses H5N6 and H7N9). The results showed that all the three humanized mAbs (F10, H98 and H40) displayed different degrees of virus neutralization activities when encountered with different subtypes of influenza viruses. Remarkably, the humanized monoclonal antibody F10 produced higher and broader neutralization titers (range 25–1.56 μg/ml) than those of the other two humanized mAbs (H98 (range 50–3.12 μg/ml), H40 (range 50–5.56 μg/ml)) to against the viruses H5N1, H1N1, H3N2, H7N7, H5N6 and H7N9. This mAb may represent a new class of heterosubtypic neutralizing humanized mAb that could replace vaccines and chemical drugs.