Advances of CRISPR-Cas13 system in COVID-19 diagnosis and treatment.

The ongoing global pandemic of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in over 570 million infections and 6 million deaths worldwide. Early detection and quarantine are essential to arrest the spread of the highly contagious COVID-19. High-risk groups, such as older adults and individuals with comorbidities, can present severe symptoms, including pyrexia, pertussis, and acute respiratory distress syndrome, on SARS-CoV-2 infection that can prove fatal, demonstrating a clear need for high-throughput and sensitive platforms to detect and eliminate SARS-CoV-2. CRISPR-Cas13, an emerging CRISPR system targeting RNA with high specificity and efficiency, has recently drawn much attention for COVID-19 diagnosis and treatment. Here, we summarized the current research progress on CRISPR-Cas13 in COVID-19 diagnosis and treatment and highlight the challenges and future research directions of CRISPR-Cas13 for effectively counteracting COVID-19.

Large-Sized Graphene Oxide Nanosheets Increase DC-T-Cell Synaptic Contact and the Efficacy of DC Vaccines against SARS-CoV-2.

Dendritic cell (DC) vaccines are used for cancer and infectious diseases, albeit with limited efficacy. Modulating the formation of DC-T-cell synapses may greatly increase their efficacy. The effects of graphene oxide (GO) nanosheets on DCs and DC-T-cell synapse formation are evaluated. In particular, size-dependent interactions are observed between GO nanosheets and DCs. GOs with diameters of >1 µm (L-GOs) demonstrate strong adherence to the DC surface, inducing cytoskeletal reorganization via the RhoA-ROCK-MLC pathway, while relatively small GOs (≈500 nm) are predominantly internalized by DCs. Furthermore, L-GO treatment enhances DC-T-cell synapse formation via cytoskeleton-dependent membrane positioning of integrin ICAM-1. L-GO acts as a "nanozipper," facilitating the aggregation of DC-T-cell clusters to produce a stable microenvironment for T cell activation. Importantly, L-GO-adjuvanted DCs promote robust cytotoxic T cell immune responses against SARS-CoV-2 spike 1, leading to >99.7% viral RNA clearance in mice infected with a clinically isolated SARS-CoV-2 strain. These findings highlight the potential value of nanomaterials as DC vaccine adjuvants for modulating DC-T-cell synapse formation and provide a basis for the development of effective COVID-19 vaccines.

Viral tests of hospitalized patients with acute respiratory tract infection in a hospital of Beijing

OBJECTIVE: To analyze the results of viral nucleic acid tests for clinical specimens of the hospitalized patients with acute respiratory tract infection(ARTI) so as to provide guidance for prevention, diagnosis and treatment of ARTI. METHODS: Totally 479 patients with ARTI who were treated in Beijing Tongren Hospital Affiliated to Capital Medical University from Jan 1, 2017 to Jan 1, 2020 were enrolled in the study, the results of tests for 14 types of viruses(subtypes) such as FluA-H1, FluA-H3, FluB, parainfluenza virusI-IV, coronavirus OC43, 229 E, NL63, respiratory syncytial virus, human rhinovirus, human metapneumovirus and adenovirus in the clinical specimens were retrospectively collected. The isolation rates of the viruses and etiological and epidemiological characteristics of the patients with ARTI were observed and compared among the age groups and different seasons. RESULTS: A total of 259 strains of viruses were isolated from sputum, alveolar lavage fluid and nasopharyngeal swab specimens of 479 patients, with the isolation rate 54.1%(259/479). Among the 14 types of respiratory tract viruses isolated, the isolation rates of FluA-H1, FluA-H3, human rhinovirus, adenovirus and FluB were 42.1%(109/259), 19.7%(51/259), 8.9%(23/259), 6.2%(16/259) and 5.4%(14/259), respectively. The FluA-H1 was prevalent in autumn and winter, adenovirus was prevalent in summer, parainfluenza virusI was prevalent in summer, as compared with other seasons, there was significant difference(P<0.05);there was no significant difference in the isolation rates of other viruses among the seasons;there were no significant differences in the isolation rates of viruses among the age groups. CONCLUSION: There are a variety of viruses isolated from the clinical specimens of the hospitalized patients with ARTI, the influenza viruses are dominant and are prevalent in autumn and winter. The elderly patients are dominant among the hospitalized patients with the infection.