title: B lymphocyte activation by human papillomavirus-like particles directly induces Ig class switch recombination via TLR4-MyD88.
abstract: Vaccination with human papillomavirus type 16 (HPV16) L1 virus-like particles (VLP) induces both high titer neutralizing IgG and protective immunity. Because protection from experimental infection by papillomavirus is mediated by neutralizing IgG, we sought the mechanisms that trigger humoral immunity to HPV16 L1 VLP. We find that HPV16 L1 VLP bind to murine B lymphocytes thereby inducing activation-induced cytidine deaminase expression and Ig class switch recombination to cause the generation of IgG. HPV16 L1 VLP also activate production of proinflammatory factors IFN-alpha, IL-6, MIP-1alpha, RANTES, and KC, up-regulate the expression of costimulatory molecules by naive B cells, and increase the B1 B cell subpopulation. These B cell responses to HPV16 L1 VLP are dependent upon MyD88. Although MyD88(-/-) B cells produce only mu transcript after exposure to HPV16 L1 VLP, MyD88(+/+) B cells express alpha, gamma, and mu Ig H chain and activation-induced cytidine deaminase transcripts. Notably, TLR4 mutant C3H/HeJ mice exhibited significantly reduced HPV16 VLP-specific IgG1, IgG2a, IgG2b, and IgG3 titers after vaccination as compared with the control C3H/HeOuJ mice. HPV16 L1 VLP directly activated class switch recombination and costimulatory molecule expression by B cells of C3H/HeOuJ mice but not C3H/HeJ mice. Thus HPV16 L1 VLP directly activate B cells to induce CD4(+) T cell independent humoral immune responses via TLR4- and MyD88-dependent signaling.
authors.affiliation: Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Rongcun
authors.initials: R
authors.lastname: Yang
authors.forename: Francisco Martinez
authors.initials: FM
authors.lastname: Murillo
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Delannoy
authors.forename: R Lee
authors.initials: RL
authors.lastname: Blosser
authors.forename: William H
authors.initials: WH
authors.lastname: Yutzy
authors.forename: Satoshi
authors.initials: S
authors.lastname: Uematsu
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Takeda
authors.forename: Shizuo
authors.initials: S
authors.lastname: Akira
authors.forename: Raphael P
authors.initials: RP
authors.lastname: Viscidi
authors.forename: Richard B S
authors.initials: RB
authors.lastname: Roden
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000943:Antigens, Differentiation / Q000235:genetics / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000473:pathology / Q000821:virology; D023201:CD40 Ligand / Q000502:physiology; D036022:Capsid Proteins; D017578:Immunoglobulin Class Switching / Q000235:genetics; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000502:physiology; D015847:Interleukin-4 / Q000502:physiology; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88; D009856:Oncogene Proteins, Viral / Q000008:administration & dosage / Q000276:immunology*; D027383:Papillomaviridae / Q000276:immunology; D011971:Receptors, Immunologic / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology / Q000378:metabolism / Q000821:virology; D051197:Toll-Like Receptor 4; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014771:Virion / Q000235:genetics / Q000276:immunology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000943:Antigens, Differentiation; D036022:Capsid Proteins; C114580:HPV L1 protein, Human papillomavirus; D007074:Immunoglobulin G; C507779:MYD88 protein, human; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D009856:Oncogene Proteins, Viral; D011971:Receptors, Immunologic; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D022223:Vaccines, Subunit; D023201:CD40 Ligand; D015847:Interleukin-4