title: Primary deficiency of microsomal triglyceride transfer protein in human abetalipoproteinemia is associated with loss of CD1 function.
abstract: Abetalipoproteinemia (ABL) is a rare Mendelian disorder of lipid metabolism due to genetic deficiency in microsomal triglyceride transfer protein (MTP). It is associated with defects in MTP-mediated lipid transfer onto apolipoprotein B (APOB) and impaired secretion of APOB-containing lipoproteins. Recently, MTP was shown to regulate the CD1 family of lipid antigen-presenting molecules, but little is known about immune function in ABL patients. Here, we have shown that ABL is characterized by immune defects affecting presentation of self and microbial lipid antigens by group 1 (CD1a, CD1b, CD1c) and group 2 (CD1d) CD1 molecules. In dendritic cells isolated from ABL patients, MTP deficiency was associated with increased proteasomal degradation of group 1 CD1 molecules. Although CD1d escaped degradation, it was unable to load antigens and exhibited functional defects similar to those affecting the group 1 CD1 molecules. The reduction in CD1 function resulted in impaired activation of CD1-restricted T and invariant natural killer T (iNKT) cells and reduced numbers and phenotypic alterations of iNKT cells consistent with central and peripheral CD1 defects in vivo. These data highlight MTP as a unique regulator of human metabolic and immune pathways and reveal that ABL is not only a disorder of lipid metabolism but also an immune disease involving CD1.
authors.affiliation: Division of Gastroenterology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Zeissig
authors.forename: Stephanie K
authors.initials: SK
authors.lastname: Dougan
authors.forename: Duarte C
authors.initials: DC
authors.lastname: Barral
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Junker
authors.forename: Zhangguo
authors.initials: Z
authors.lastname: Chen
authors.forename: Arthur
authors.initials: A
authors.lastname: Kaser
authors.forename: Madelyn
authors.initials: M
authors.lastname: Ho
authors.forename: Hannah
authors.initials: H
authors.lastname: Mandel
authors.forename: Adam
authors.initials: A
authors.lastname: McIntyre
authors.forename: Susan M
authors.initials: SM
authors.lastname: Kennedy
authors.forename: Gavin F
authors.initials: GF
authors.lastname: Painter
authors.forename: Natacha
authors.initials: N
authors.lastname: Veerapen
authors.forename: Gurdyal S
authors.initials: GS
authors.lastname: Besra
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cerundolo
authors.forename: Simon
authors.initials: S
authors.lastname: Yue
authors.forename: Sarah
authors.initials: S
authors.lastname: Beladi
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Behar
authors.forename: Xiuxu
authors.initials: X
authors.lastname: Chen
authors.forename: Jenny E
authors.initials: JE
authors.lastname: Gumperz
authors.forename: Karine
authors.initials: K
authors.lastname: Breckpot
authors.forename: Anna
authors.initials: A
authors.lastname: Raper
authors.forename: Amanda
authors.initials: A
authors.lastname: Baer
authors.forename: Mark A
authors.initials: MA
authors.lastname: Exley
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hegele
authors.forename: Marina
authors.initials: M
authors.lastname: Cuchel
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Rader
authors.forename: Nicholas O
authors.initials: NO
authors.lastname: Davidson
authors.forename: Richard S
authors.initials: RS
authors.lastname: Blumberg
mesh_terms: D000012:Abetalipoproteinemia / Q000276:immunology*; D000328:Adult; D017951:Antigen Presentation; D018949:Antigens, CD1 / Q000502:physiology*; D055610:Antigens, CD1d / Q000502:physiology; D002352:Carrier Proteins / Q000502:physiology*; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D018664:Interleukin-12 / Q000502:physiology; D008297:Male; D008875:Middle Aged; D055611:Natural Killer T-Cells / Q000276:immunology; D055815:Young Adult
chemical_list: D018949:Antigens, CD1; D055610:Antigens, CD1d; C526877:CD1D protein, human; D002352:Carrier Proteins; C106092:microsomal triglyceride transfer protein; D018664:Interleukin-12