Antibodies to the N-Terminal Domain of Angiotensin-Converting Enzyme (ACE2) That Block Its Interaction with SARS-CoV-2 S Protein.

SARS-CoV-2 is a new coronavirus that is the cause of COVID-19 pandemic. To enter the cell, the virus interacts via its surface S protein with angiotensin-converting enzyme 2 (ACE2), the main entry receptor on the cell membrane. Most of protective antibodies, including those induced by vaccinations, target the S protein, preventing its interaction with the ACE2 receptor. We have evaluated an alternative strategy for blocking the S-ACE2 interaction using new antipeptide antibodies to the N-terminus of the ACE2 molecule. These antibodies allow detection of human ACE2 in vitro and ex vivo.

Prospects for using the ELISPOT technological platform as part of anti-epidemic measures against the new coronavirus infection covid-19

Determination of T-cell immune response to SARS-CoV-2 is important both for diagnosis of the disease in symptomatic patients, and for determination of the total number of people who have had the disease, including its asymptomatic form. In addition, these assays are efficient for assessing the immune response after vaccination, as well as immunity levels in risk groups and in convalescent patients. The most promising method of T-cell immune response assessment is an ELISPOT-based assay measuring the release of interferon-gamma (IGRA) after stimulation with coronavirus-specific antigens. The present review analyses the prospects for using the ELISPOT technological platform in the clinical laboratory setting when dealing with the new coronavirus infection COVID-19, given specific aspects of the immune response. The review summarises data from articles published in peer-reviewed journals, preprints of articles available at arXiv resources, and information that some leading immunologists shared with the authors during private discussions. It has been shown that the introduction of B- and T-cell ELISPOT assays will make it possible to monitor the immunological status of patients, select a treatment strategy, identify the most vulnerable populations, carry out comprehensive assessment of vaccines during the development, clinical trials and implementation stages. The paper discusses the issues of maintaining T-cell immunity in the blood of people who have had HCoV, SARS, MERS, and COVID-19 coronavirus infections. It also discusses the advantages of the T-cell ELISPOT assay over serological tests as regards epidemiological assessment of the prevalence of the new coronavirus infection, and clinical trials of COVID-19 vaccines. Biotechnology companies have a ready-made technological platform for the development and industrial-scale production of ELISPOT kits, and this platform is easily adaptable to specific types of assays and pathogens. The paper supports the need to develop vaccines that would stimulate both cellular and humoral immune responses, and raises the question of the protective potential of cross-immunity acquired before the COVID-19 pandemic.