Wolbachia lipoprotein stimulates innate and adaptive immunity through Toll-like receptors 2 and 6 to induce disease manifestations of filariasis.
Wolbachia endosymbiotic bacteria have been implicated in the inflammatory pathogenesis of filariasis. Inflammation induced by Brugia malayi female worm extract (BMFE) is dependent on Toll-like receptors 2 and 6 (TLR2/6) with only a partial requirement for TLR1. Removal of Wolbachia, lipids, or proteins eliminates all inflammatory activity. Wolbachia bacteria contain the lipoprotein biosynthesis genes Ltg and LspA but not Lnt, suggesting Wolbachia proteins cannot be triacylated, accounting for recognition by TLR2/6. Lipoprotein databases revealed 3-11 potential lipoproteins from Wolbachia. Peptidoglycan-associated lipoprotein (PAL) and Type IV secretion system-VirB6 were consistently predicted, and B. malayi Wolbachia PAL (wBmPAL) was selected for functional characterization. Diacylated 20-mer peptides of wBmPAL (Diacyl Wolbachia lipopeptide (Diacyl WoLP)) showed a near identical TLR2/6 and TLR2/1 usage compared with BMFE and bound directly to TLR2. Diacyl WoLP induced systemic tumor necrosis factor-alpha and neutrophil-mediated keratitis in mice. Diacyl WoLP activated monocytes induce up-regulation of gp38 on human lymphatic endothelial cells and induced dendritic cell maturation and activation. Dendritic cells primed with BMFE generated a non-polarized Th1/Th2 CD4+ T cell profile, whereas priming with Wolbachia depleted extracts (following tetracycline treatment; BMFEtet) polarized to a Th2 profile that could be reversed by reconstitution with Diacyl WoLP. BMFE generated IgG1 and IgG2c antibody responses, whereas BMFEtet or inoculation of TLR2 or MyD88-/- mice produced defective IgG2c responses. Thus, in addition to innate inflammatory activation, Wolbachia lipoproteins drive interferon-gamma-dependent CD4+ T cell polarization and antibody switching.
Turner
Joseph D
JD
Filariasis Research Laboratory, Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
Langley
R Stuart
RS
Filariasis Research Laboratory, Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
Johnston
Kelly L
KL
Filariasis Research Laboratory, Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
Gentil
Katrin
K
Department of Ophthalmology, Case Western Reserve University, Cleveland, Ohio 44106.
Ford
Louise
L
Filariasis Research Laboratory, Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
Wu
Bo
B
New England Biolabs, Ipswich, Massachusetts 01938.
Graham
Maia
M
Filariasis Research Laboratory, Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
Sharpley
Faye
F
Filariasis Research Laboratory, Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
Slatko
Barton
B
New England Biolabs, Ipswich, Massachusetts 01938.
Pearlman
Eric
E
Department of Ophthalmology, Case Western Reserve University, Cleveland, Ohio 44106.
Taylor
Mark J
MJ
Filariasis Research Laboratory, Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom.
D000818:Animals; D002009:Brugia / Q000378:metabolism*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005260:Female; D005368:Filariasis / Q000378:metabolism*; D006801:Humans; D007107:Immune System; D008074:Lipoproteins / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D008954:Models, Biological; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D051216:Toll-Like Receptor 6 / Q000378:metabolism*; D020577:Wolbachia / Q000378:metabolism*
D008074:Lipoproteins; D051195:Toll-Like Receptor 2; D051216:Toll-Like Receptor 6