Universities of Kent and Greenwich at Medway 1 article published in JoVE Immunology and Infection Pseudotyped Viruses As a Molecular Tool to Monitor Humoral Immune Responses Against SARS-CoV-2 Via Neutralization Assay Tobia Fantoni*1, Michele Bissoli*1, Chiara Stefani1, Mauro Voi1, Alexandrina Dabija1, Rebecca Casula1, Domenico Luca Minafra1, Julys da Fonseca Palmeira2, Enrique Roberto Argañaraz2, Martin Mayora-Neto3, Nigel J. Temperton3, Donato Zipeto1, Alessandra Ruggiero1 1Department of Neuroscience, Biomedicine and Movement, University of Verona, 2Laboratory of Molecular Neurovirology, Faculty of Health Science, University of Brasília, 3Viral Pseudotype Unit, Medway School of Pharmacy, Universities of Kent and Greenwich at Medway Pseudotyped viruses (PVs) are replication-defective virions that are used to study host-virus interactions under safer conditions than handling authentic viruses. Presented here is a detailed protocol that shows how SARS-CoV-2 PVs can be used to test the neutralizing ability of patients' serum after COVID-19 vaccination.