Pseudotyping Lentivirus in 293T cells to Measure Antibodies that Block Entry of Respiratory Syncytial VirusdissertationsParakh, HarshinicreatorJamieson, AmandaReaderNau, GerardAdvisorTripathi, AnubhavReaderBrown University. Biology and Medicine: Biotechnologysponsor2025, 42 p.born digitalThesis (Sc. M.)--Brown University, 2025thesesRespiratory syncytial virus (RSV) is a significant cause of respiratory illness in the elderly, necessitating effective vaccines and reliable methods to measure immune responses. This study aimed to measure vaccine-induced neutralizing antibody responses to RSV using a pseudotyped lentivirus system in a high-risk elderly cohort. Pre- and post-vaccination serum samples from nursing home residents were tested using a pseudotyped lentiviral vector generated in 293T cells expressing the RSV fusion (F) long protein. Neutralization assays were conducted to measure functional antibody activity against RSV, while enzyme-linked immunosorbent assays (ELISA) quantified total RSV-specific antibodies. Post-vaccination samples showed a significant rise in neutralizing titers against the RSV F protein from both the A2 and B strains of the virus, indicating that vaccination elicited robust F-specific neutralizing antibodies across subtypes. In contrast, no significant increase in antibodies against the RSV attachment (G) glycoprotein was observed, reflecting the fact that the vaccine is comprised only of F protein. ELISA results confirmed an overall increase in RSV-specific antibody levels after vaccination and were modestly correlated with neutralization titers, suggesting that not all binding antibodies had neutralizing capability. These findings demonstrate that the 293T cell-based pseudotyped lentivirus neutralization assay is a potential tool for evaluating RSV vaccine-induced immunity. The F-specific neutralizing antibody response supports the RSV F protein as a promising target for vaccines, particularly to protect high-risk elderly populations such as nursing home residents.Immune responseRespiratory syncytial virusPseudotypingClinical serum samplesEnglishRPB20250707