title: Enhanced antibody responses to an HIV-1 membrane-proximal external region antigen in mice reconstituted with cultured lymphocytes.
abstract: We have shown that the protective HIV-1 Ab, 2F5, avidly reacts with a conserved mammalian self-Ag, kynureninase, and that the development of B cells specific for the 2F5 epitope is constrained by immunological tolerance. These observations suggest that the capacity to mount Ab responses to the 2F5 epitope is mitigated by tolerance, but such capacity may be latent in the pretolerance and/or anergic B cell pools. In this study, we use B cell tetramer reagents to track the frequencies of B cells that recognize the HIV-1 2F5 epitope (SP62): in C57BL/6 mice, SP62-binding transitional B cells are readily identified in bone marrow but are lost during subsequent development. Unsurprisingly then, immunization with SP62 immunogen does not elicit significant humoral responses in normal C57BL/6 mice. Reconstitution of Rag1(null) mice with normal congenic B cells that have matured in vitro restores the capacity to mount significant serum Ab and germinal center responses to this HIV-1 epitope. These B cell cultures are permissive for the development of autoreactive B cells and support the development of SP62-specific B cell compartments normally lost in 2F5 Ab knockin mice. The recovery of humoral responses to the 2F5/SP62 epitope of HIV-1 by reconstitution with B cells containing forbidden, autoreactive clones provides direct evidence that normal C57BL/6 mice latently possess the capacity to generate humoral responses to a conserved, neutralizing HIV-1 epitope.
authors.affiliation: Department of Immunology, Duke University, Durham, NC 27710;
authors.forename: T Matt
authors.initials: TM
authors.lastname: Holl
authors.forename: Guang
authors.initials: G
authors.lastname: Yang
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kuraoka
authors.forename: Laurent
authors.initials: L
authors.lastname: Verkoczy
authors.forename: S Munir
authors.initials: SM
authors.lastname: Alam
authors.forename: M Anthony
authors.initials: MA
authors.lastname: Moody
authors.forename: Barton F
authors.initials: BF
authors.lastname: Haynes
authors.forename: Garnett
authors.initials: G
authors.lastname: Kelsoe
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000276:immunology*; D000956:Antigens, Viral / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology / Q000378:metabolism; D005434:Flow Cytometry; D018858:Germinal Center / Q000276:immunology / Q000378:metabolism; D015483:HIV Antibodies / Q000097:blood / Q000276:immunology; D015700:HIV Envelope Protein gp41 / Q000276:immunology / Q000378:metabolism; D015497:HIV-1 / Q000276:immunology*; D007108:Immune Tolerance / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology*; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011485:Protein Binding / Q000276:immunology; D013154:Spleen / Q000276:immunology / Q000378:metabolism
chemical_list: D000956:Antigens, Viral; D000939:Epitopes; D015483:HIV Antibodies; D015700:HIV Envelope Protein gp41