title: Vaccine evaluation studies of replication-defective SIVsmB7.
abstract: Non-infectious virus-like particles of SIVsmB7 that expresses env and gag gene products but are defective in pol and vpx/vpr were assessed for their ability to induce protective immunity against infection with pathogenic SIVsmE660 in rhesus macaques. Animals were immunized in three groups: group A was primed with cell-associated SIVsmB7 and boosted with cell-free SIVsmB7; group B was primed with cell-free SIVsmB7 and boosted with cell-free SIVsmB7 conjugated to iron oxide microbeads; group C was primed with cell-free SIVsmB7 mixed with Titer Max adjuvant and boosted with cell-free SIVsmB7 mixed with SAF-M adjuvant followed by secondary boosting with cell-free SIVsmB7 conjugated to microbeads. Animals were challenged intravenously with 20 animal infectious doses of SIVsmE660 grown in rhesus peripheral blood mononuclear cells 3 weeks after final boosting. All animals became infected as evidenced by quantitative virus cultivation. Sera from immunized animals contained low-titer antibodies by ELISA and low or undetectable neutralizing antibodies on the day of challenge but strong anamnestic antibody responses were observed following challenge. Interestingly, 2 of 3 animals in group A showed evidence of transient viremia and more stable CD4 counts following challenge as compared to the other immunized animals and to non-immunized controls. Thus, immunization with cell-associated SIVsmB7 did not provide sterilizing immunity against challenge with a highly pathogenic SIV strain but might have caused virus clearance later in infection.
authors.affiliation: Department of Microbiology and Medical Zoology, School of Medicine, University of Puerto Rico, San Juan 00936, USA.
authors.forename: E N
authors.initials: EN
authors.lastname: Kraiselburd
authors.forename: A
authors.initials: A
authors.lastname: Salaman
authors.forename: M
authors.initials: M
authors.lastname: Beltrán
authors.forename: M
authors.initials: M
authors.lastname: Rivera
authors.forename: J
authors.initials: J
authors.lastname: Oliver
authors.forename: M
authors.initials: M
authors.lastname: Kessler
authors.forename: M
authors.initials: M
authors.lastname: Knezevich
authors.forename: A
authors.initials: A
authors.lastname: Rodriguez
authors.forename: M
authors.initials: M
authors.lastname: Bilska
authors.forename: D
authors.initials: D
authors.lastname: Montefiori
authors.forename: L J
authors.initials: LJ
authors.lastname: Torres-Bauza
authors.forename: I
authors.initials: I
authors.lastname: Martinez
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D002460:Cell Line; D003673:Defective Viruses / Q000276:immunology*; D008253:Macaca mulatta; D008297:Male; D018449:SAIDS Vaccines / Q000009:adverse effects / Q000276:immunology*; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000517:prevention & control; D015302:Simian Immunodeficiency Virus / Q000276:immunology* / Q000302:isolation & purification; D016896:Treatment Outcome; D014779:Virus Replication / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D018449:SAIDS Vaccines