• antibody libraries convalescent COVID-19 patients
• SARS-CoV-2 antibodies

COVID-19 is an acute infectious disease caused by coronavirus 2 (SARS-CoV-2). SARS-CoV-2 spike (S) protein binds to the angiotensin-converting enzyme-2 (ACE2) receptor to invade alveolar epithelial cells, promotes toxicity and excessive immune responses, leading to death. To fight the pandemic of COVID-19, researchers around the world are working on development of several candidate vaccines and effective therapeutic treatments such as antibodies that could be both preventive and therapeutic tools. The aim of my thesis was to create recombinant antibody domain libraries (single-chain variable fragment (scFv)) from blood of 6 patients that recovered from COVID-19. These libraries immortalize and “freeze” the genetic information of the antibody response of each patient. They can be exploited repeatedly, to select different antibodies against viral proteins. These libraries have been constructed and fully sequenced. The library of one patient has been used in a first screening by the IACT (intracellular antibody capture technology) strategy to select antibody domains against some SARS-CoV-2 antigens. In the screening performed in this thesis, the receptor binding domain (RBD) of SARS-CoV-2 S protein has been chosen as the bait and the IgM and IgG/IgA libraries obtained from a COVID-19 recovered patient represented the prey. The ultimate perspective of this project is the clinical use of the isolated human scFv domains.