biostudies-literaturePauthner MGTranslational Virology Core at the UC San Diego Center for AIDS ResearchIGM Genomics Center, University of California, San Diego, La Jolla, CaliforniaNIAID NIH HHSAchievement Rewards for College Scientists FoundationNational Institutes of HealthNIHNIAIDCanada Research Chair on Retroviral EntryCIHRCIHR FellowshipInternational AIDS Vaccine InitiativeNational Institute of Allergy and Infectious DiseasesBill & Melinda Gates FoundationCIHR foundationNIH HHS241-252.e6https://www.ebi.ac.uk/biostudies/studies/S-EPMC6335502biostudies-literatureUnknown50(1)Passive administration of HIV neutralizing antibodies (nAbs) can protect macaques from hard-to-neutralize (tier 2) chimeric simian-human immunodeficiency virus (SHIV) challenge. However, conditions for nAb-mediated protection after vaccination have not been established. Here, we selected groups of 6 rhesus macaques with either high or low serum nAb titers from a total of 78 animals immunized with recombinant native-like (SOSIP) Env trimers. Repeat intrarectal challenge with homologous tier 2 SHIVBG505 led to rapid infection in unimmunized and low-titer animals. High-titer animals, however, demonstrated protection that was gradually lost as nAb titers waned over time. An autologous serum ID50 nAb titer of ∼1:500 afforded more than 90% protection from medium-dose SHIV infection. In contrast,ImmunityVaccine-Induced Protection from Homologous Tier 2 SHIV Challenge in Nonhuman Primates Depends on Serum-Neutralizing Antibody Titers.PMC6335502UM1AI068618352417AI121135R01 AI095098AI126603RCHS0235R01 AI098485R01 AI136621UM1 AI068618R01 AI131331OPP1145046AI136621U19 AI128751R01 AI121135P30 AI036214R00 AI120851R00AI120851F31 AI131873UM1 AI126603Al131873AI124377OPP1084519UM1 AI124377UM1AI100663OD011106P01 AI131251AI128751UM1 AI100663P51 OD011106Irvine DJEvans DTBastidas RHavenar-Daughton CReiss SMvon Bredow BBurton DRShaw GMFinzi ACrotty SWyatt RTKulp DWNogal BWard ABSchief WRCottrell CALee JHLi HSanders RWTokatlian TButera STBarouch DHBianchi MWilson IAPrevost JHangartner LPauthner MGMurrell BAbbink PNkolola JPNedellec RfalseVaccine-Induced Protection from Homologous Tier 2 SHIV Challenge in Nonhuman Primates Depends on Serum-Neutralizing Antibody Titers.Passive administration of HIV neutralizing antibodies (nAbs) can protect macaques from hard-to-neutralize (tier 2) chimeric simian-human immunodeficiency virus (SHIV) challenge. However, conditions for nAb-mediated protection after vaccination have not been established. Here, we selected groups of 6 rhesus macaques with either high or low serum nAb titers from a total of 78 animals immunized with recombinant native-like (SOSIP) Env trimers. Repeat intrarectal challenge with homologous tier 2 SHIVBG505 led to rapid infection in unimmunized and low-titer animals. High-titer animals, however, demonstrated protection that was gradually lost as nAb titers waned over time. An autologous serum ID50 nAb titer of ∼1:500 afforded more than 90% protection from medium-dose SHIV infection. In contrast,2019-01-01T00:00:00Z2019 Jan2025-04-26T07:05:48.328Z2019-03-26T22:38:51ZS-EPMC63355023055202510.1016/j.immuni.2018.11.011