title: Effect of humoral immune responses on controlling viremia during primary infection of rhesus monkeys with simian immunodeficiency virus.
abstract: Cellular immune responses mediated by CD8+ lymphocytes exert efficient control of virus replication during primary simian immunodeficiency virus (SIV) infection. However, the role that antibodies may play in the early control of virus replication remains unclear. To evaluate how antibody responses may affect virus replication during primary SIVmac infection, we depleted rhesus monkeys of B cells with anti-CD20 antibody. In normal rhesus monkeys immunized with tetanus toxoid, anti-CD20 treatment and resulting depletion of B cells inhibited the generation of antitetanus antibodies, while tetanus-specific T-cell responses were preserved. During the first 4 weeks after inoculation with SIVmac251, development of SIV-specific neutralizing antibody was delayed, and titers were significantly lower in B-cell-depleted monkeys than control-antibody-treated monkeys. Despite the lower neutralizing antibody titers, the levels of plasma SIV RNA and the linear slope of the decline seen in B-cell-depleted monkeys did not differ from that observed in monkeys treated with control antibody. However, beginning at day 28 after SIV infection, the B-cell-depleted monkeys showed a significant inverse correlation between neutralizing antibody titers and plasma virus level. These results suggest that the rapid decline of peak viremia that typically occurs during the first 3 weeks of infection was not significantly affected by SIV-specific antibodies. However, the inverse correlation between neutralizing antibodies and plasma virus level during the postacute phases of infection suggests that humoral immune responses may contribute to the control of SIV replication.
authors.affiliation: Division of Viral Pathogenesis, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
authors.forename: Jörn E
authors.initials: JE
authors.lastname: Schmitz
authors.forename: Marcelo J
authors.initials: MJ
authors.lastname: Kuroda
authors.forename: Sampa
authors.initials: S
authors.lastname: Santra
authors.forename: Meredith A
authors.initials: MA
authors.lastname: Simon
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Lifton
authors.forename: Wenyu
authors.initials: W
authors.lastname: Lin
authors.forename: Rajinder
authors.initials: R
authors.lastname: Khunkhun
authors.forename: Michael
authors.initials: M
authors.lastname: Piatak
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Lifson
authors.forename: Gudrun
authors.initials: G
authors.lastname: Grosschupff
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Gelman
authors.forename: Paul
authors.initials: P
authors.lastname: Racz
authors.forename: Klara
authors.initials: K
authors.lastname: Tenner-Racz
authors.forename: Keith A
authors.initials: KA
authors.lastname: Mansfield
authors.forename: Norman L
authors.initials: NL
authors.lastname: Letvin
authors.forename: David C
authors.initials: DC
authors.lastname: Montefiori
authors.forename: Keith A
authors.initials: KA
authors.lastname: Reimann
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000096:biosynthesis*; D018951:Antigens, CD20 / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D008213:Lymphocyte Activation; D008253:Macaca mulatta; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology*; D015302:Simian Immunodeficiency Virus; D014766:Viremia / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D018951:Antigens, CD20