نبذة مختصرة : The ability of antibodies to block infections makes them highly relevant for successful vaccine development. Through the papers described in this thesis, I attempt to characterize the functional and genetic aspects of antiviral antibodies induced by infection and vaccination. In Paper I, we characterized the distribution and maturation of HIV-1 envelope glycoproteins (Env)-specific antibody lineages post-vaccination in different immune compartments of rhesus macaques. Vaccine-induced Env-specific antibody lineages were disseminated across the periphery, lymph node, spleen, and bone marrow (BM) but not in gut tissue. We observed a consistent increase in the somatic hypermutation (SHM) levels of Env-specific antibody sequences after each boost and the SHM levels strongly correlated with the affinity of members from a potent neutralizing antibody lineage. In Paper II, we set out to understand the role of SHM in a broad, potent, public class of antibodies isolated from a healthcare worker who was previously infected with SARS-CoV2. I selected a potent neutralizing antibody and reverted the heavy chain (HC) to the germline sequence. I then sequentially introduced individual or combinations of SHM so that we could test the functional impact of this. We found a substantial gain of antibody potency and breadth when certain SHM mutations were reintroduced, and we identified two key mutations that largely contributed to the breadth of this lineage. Furthermore, we showed that the mature antibody retained neutralizing activity against potential future viral variants by deep mutational scanning (DMS) experiments. A high-resolution structure of this antibody obtained by cryo-electron microscopy (cryo-EM) confirmed important interactions made by the identified SHMs with the SARS-CoV-2 spike (S). In Papers III and IV, we investigated the effect of immunoglobulin heavy chain variable (IGHV) gene polymorphisms on the function of human SARS-CoV-2 antibodies isolated post-infection. We genotyped a cohort of previously infected ...
Relation: I. Phad GE, Pushparaj P, Tran K, Dubrovskaya V, Àdori M, Martinez Murillo P, Vázquez Bernat N, Singh S, Dionne G, O'Dell S, Bhullar K, Narang S, Sorini C, Villablanca EJ, Sundling C, Murrell B, Mascola JR, Shapiro L, Pancera M, Martin M, Corcoran M, Wyatt RT, Karlsson Hedestam GB. Extensive dissemination and intraclonal maturation of HIV Env vaccine-induced B cell responses. Journal of Experimental Medicine. February 2020; 217(2):e20191155. ::doi::10.1084/jem.20191155 ::pmid::31704807 ::isi::000523657100016; II. Sheward DJ*, Pushparaj P*, Das H*, Greaney AJ, Kim C, Kim S, Hanke L, Dyrdak R, Lee J, Peacock TP, McInerney G, Albert J, Corcoran M, Bloom JD, Murrell B#, Karlsson Hedestam GB#, Hällberg BM.# Structural basis of broad SARS-CoV-2 cross-neutralization by affinity-matured public antibodies. *These authors contributed equally. [Submitted]; III. Pushparaj P, Nicoletto A*, Sheward DJ*, Das H, Castro Dopico X, Perez Vidakovics L, Hanke L, Chernyshev M, Narang S, Kim S, Fischbach J, Ekström S, McInerney G, Hällberg BM, Murrell B, Corcoran M, Karlsson Hedestam GB. Immunoglobulin germline gene polymorphisms influence the function of SARS-CoV-2 neutralizing antibodies. Immunity. January 2023; 56(1):193-206. *These authors contributed equally. ::doi::10.1016/j.immuni.2022.12.005 ::pmid::36574772 ::isi::000924747300001; IV. Pushparaj P, Nicoletto A, Castro Dopico X, Sheward DJ, Sungyong Kim, Ekström S, Murrell B, Corcoran M and Karlsson Hedestam GB. Frequent usage of IGHV3-30-3 in SARS-CoV-2 neutralizing antibody responses. Frontiers in Virology. March 2023, Vol 3. ::doi::10.3389/fviro.2023.1128253; http://hdl.handle.net/10616/48552
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