title: Protective antibodies develop, and murine Lyme arthritis regresses, in the absence of MHC class II and CD4+ T cells.
abstract: Murine Lyme borreliosis is characterized by arthritis and carditis that are most severe at 2 to 3 wk, then regress during the course of persistent infection. Borrelia burgdorferi-specific Abs and CD4+ T cells have been implicated in the resolution phase of arthritis. Therefore, MHC class II transactivator (CIITA)-deficient mice that do not express conventional class II molecules and lack the normal CD4 repertoire were used to investigate the role of MHC class II-mediated responses in Lyme disease. The development of arthritis and carditis, and the resolution of arthritis, were similar in CIITA-deficient and control C57/BL6 mice. In contrast, the resolution of carditis was delayed in CIITA-deficient animals compared with controls. Moreover, CIITA-deficient mice developed B. burgdorferi-specific IgG2b Abs, and sera from these animals passively protected naive C3H/HeN mice from challenge inoculation and cleared B. burgdorferi from 2 day-infected C.B.17 SCID mice. These data suggest that CD4+ T cells and MHC class II-mediated responses are not required for the generation of protective Abs or the regression of arthritis, but may be important in the resolution of Lyme carditis in mice.
authors.affiliation: Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520, USA.
authors.forename: E
authors.initials: E
authors.lastname: Fikrig
authors.forename: S W
authors.initials: SW
authors.lastname: Barthold
authors.forename: M
authors.initials: M
authors.lastname: Chen
authors.forename: C H
authors.initials: CH
authors.lastname: Chang
authors.forename: R A
authors.initials: RA
authors.lastname: Flavell
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D000920:Antibody-Dependent Cell Cytotoxicity; D001170:Arthritis, Infectious / Q000276:immunology*; D015748:Borrelia burgdorferi Group / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007114:Immunization; D008193:Lyme Disease / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H; D016513:Mice, SCID
chemical_list: D000907:Antibodies, Bacterial; D000949:Histocompatibility Antigens Class II