title: Analysis of SIVmac Envelope-Specific Antibodies Selected Through Phage Display.
abstract: We have constructed a single chain fragment variable (scFv) phage display library from a simian immunodeficiency virus (SIV)-infected rhesus macaque that developed unusually high-titer neutralizing antibody responses against tier-3, neutralization-resistant SIVmac239. The library was screened using trimeric (gp140) and monomeric (gp120) forms of the SIVmac239 envelope (Env) glycoprotein. We also cloned variable-heavy and variable-light (VH-VL) antibody fragments from seven previously described rhesus macaque B-cell lines (BLCLs) that produce SIV gp120-specific monoclonal antibodies (mAbs). Thirty-two gp140-specific mAbs were selected along with 20 gp120-specific ones. gp120-specific mAbs were only from the VH4 family, while gp41-specific mAbs were primarily from VH1, followed by VH4 and VH3. Rhesus macaque BLCL-derived mAbs belonged primarily to the VH4 family of antibodies followed by VH3 and a smaller number of VH1s. A preferential VH combination with Vλ light chain was observed with phage display-selected SIV Env-specific mAbs (gp120 and gp140), but not with BLCL-derived antibodies or the unpanned library. None of the tested antibodies had detectable neutralizing activity against tier-3 SIVmac239. The majority of gp120-specifc mAbs potently neutralized tier-1 SIVmac316 with 50% inhibitory concentration (IC50) values below 1 μg/ml. For gp140-specific antibodies, which were all specific for the gp41-subunit, 2 out of 11 tested neutralized SIVmac316 (IC50 of 7 and 5 μg/ml, respectively). These data suggest an order of preferential VH segment usage for SIV-specific antibodies in rhesus macaques. These antibodies will be useful in assessing the contribution of non-neutralizing antibodies to inhibition of SIV infection in vitro and in vivo.
authors.affiliation: 1 Biology Department, Boston College , Chestnut Hill, Massachusetts.|2 Virology Program, Harvard Medical School , Boston, Massachusetts.
authors.forename: Sergio
authors.initials: S
authors.lastname: Ita
authors.affiliation: 1 Biology Department, Boston College , Chestnut Hill, Massachusetts.|3 Brazil Scientific Mobility Program, College of Nursing, University of New Mexico , Albuquerque, New Mexico.
authors.forename: Mayara R
authors.initials: MR
authors.lastname: Agostinho
authors.affiliation: 1 Biology Department, Boston College , Chestnut Hill, Massachusetts.
authors.forename: Katherine
authors.initials: K
authors.lastname: Sullivan
authors.affiliation: 1 Biology Department, Boston College , Chestnut Hill, Massachusetts.
authors.forename: Seung
authors.initials: S
authors.lastname: Yub Han
authors.affiliation: 1 Biology Department, Boston College , Chestnut Hill, Massachusetts.
authors.forename: Rana
authors.initials: R
authors.lastname: Akleh
authors.affiliation: 1 Biology Department, Boston College , Chestnut Hill, Massachusetts.
authors.forename: Welkin E
authors.initials: WE
authors.lastname: Johnson
authors.affiliation: 1 Biology Department, Boston College , Chestnut Hill, Massachusetts.
authors.forename: Ismael Ben F
authors.initials: IBF
authors.lastname: Fofana
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology / Q000302:isolation & purification; D000914:Antibodies, Viral / Q000276:immunology* / Q000302:isolation & purification*; D020128:Inhibitory Concentration 50; D008253:Macaca mulatta; D008403:Mass Screening; D009500:Neutralization Tests; D019151:Peptide Library; D015302:Simian Immunodeficiency Virus / Q000276:immunology*; D057127:Single-Chain Antibodies / Q000276:immunology* / Q000302:isolation & purification*; D014759:Viral Envelope Proteins / Q000276:immunology*
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D019151:Peptide Library; D057127:Single-Chain Antibodies; D014759:Viral Envelope Proteins
keywords: SIV; VH usage; antibodies; envelope; phage display