ABSTRACT
Different humanized mouse models have been developed to study human diseases such as autoimmune illnesses, cancer and viral infections. These models are based on the use of immunodeficient mouse strains that are transplanted with human tissues or human immune cells. Among the latter, mice transplanted with hematopoietic stem cells have been widely used to study human infectious diseases. However, mouse models built upon the transplantation of donor-specific mature immune cells are still under development, especially in the field of viral infections. These models can retain the unique immune memory of the donor, making them suitable for the study of correlates of protection upon natural infection or vaccination. Here, we will review some of these models and how they have been applied to virology research. Moreover, the future applications and the potential of these models to design therapies against human viral infections are discussed.
Subject(s)
Viruses , Mice , Humans , Animals , Mice, SCID , Disease Models, Animal , Viruses/geneticsABSTRACT
The genome of coronaviruses, including SARS-CoV-2, encodes for two proteases, a papain like (PLpro ) protease and the so-called main protease (Mpro ), a chymotrypsin-like cysteine protease, also named 3CLpro or non-structural protein 5 (nsp5). Mpro is activated by autoproteolysis and is the main protease responsible for cutting the viral polyprotein into functional units. Aside from this, it is described that Mpro proteases are also capable of processing host proteins, including those involved in the host innate immune response. To identify substrates of the three main proteases from SARS-CoV, SARS-CoV-2, and hCoV-NL63 coronviruses, an LC-MS based N-terminomics in vitro analysis is performed using recombinantly expressed proteases and lung epithelial and endothelial cell lysates as substrate pools. For SARS-CoV-2 Mpro , 445 cleavage events from more than 300 proteins are identified, while 151 and 331 Mpro derived cleavage events are identified for SARS-CoV and hCoV-NL63, respectively. These data enable to better understand the cleavage site specificity of the viral proteases and will help to identify novel substrates in vivo. All data are available via ProteomeXchange with identifier PXD021406.
Subject(s)
COVID-19/virology , Coronavirus 3C Proteases/metabolism , Coronavirus NL63, Human/enzymology , Peptide Fragments/analysis , SARS-CoV-2/enzymology , Severe acute respiratory syndrome-related coronavirus/enzymology , Viral Proteins/metabolism , COVID-19/metabolism , Cells, Cultured , Endothelial Cells/metabolism , Endothelial Cells/virology , Epithelial Cells/metabolism , Epithelial Cells/virology , Eukaryotic Initiation Factor-4G/metabolism , Host-Pathogen Interactions , Humans , Lung/metabolism , Lung/virology , Substrate SpecificityABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the aetiological agent of coronavirus disease 2019 (COVID-19), an emerging respiratory infection caused by the introduction of a novel coronavirus into humans late in 2019 (first detected in Hubei province, China). As of 18 September 2020, SARS-CoV-2 has spread to 215 countries, has infected more than 30 million people and has caused more than 950,000 deaths. As humans do not have pre-existing immunity to SARS-CoV-2, there is an urgent need to develop therapeutic agents and vaccines to mitigate the current pandemic and to prevent the re-emergence of COVID-19. In February 2020, the World Health Organization (WHO) assembled an international panel to develop animal models for COVID-19 to accelerate the testing of vaccines and therapeutic agents. Here we summarize the findings to date and provides relevant information for preclinical testing of vaccine candidates and therapeutic agents for COVID-19.