Document Detail


Requirement for invariant chain in macrophages for Mycobacterium tuberculosis replication and CD1d antigen presentation.
MedLine Citation:
PMID:  21576321     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Mycobacterium tuberculosis is an intracellular bacterium that persists in phagosomes of myeloid cells. M. tuberculosis-encoded factors support pathogen survival and reduce fusion of phagosomes with bactericidal lysosomal compartments. It is, however, not entirely understood if host factors that mediate endosomal fusion affect M. tuberculosis intracellular localization and survival. Neither is it known if endosomal fusion influences induction of host immune reactivity by M. tuberculosis-infected cells. Lysosomal degradation of M. tuberculosis appears to be pivotal for making available lipid substrates for assembly into lipid-CD1d complexes to allow activation of CD1d-restricted invariant natural killer T (iNKT) cells. To clarify the role for endosomal fusion in M. tuberculosis survival and induction of host CD1d-mediated immune defense, we focused our studies on the invariant chain (Ii). Ii regulates endosome docking and fusion and thereby controls endosomal transport. Through direct binding, Ii also directs intracellular transport of the class II major histocompatibility complex and CD1d. Our findings demonstrate that upon infection of Ii-knockout (Ii(-/-)) macrophages, M. tuberculosis is initially retained in early endosomal antigen 1-positive lysosomal-associated membrane protein 1-negative phagosomes, which results in slightly impaired pathogen replication. The absence of Ii did not affect the ability of uninfected and infected macrophages to produce nitric oxide, tumor necrosis factor alpha, or interleukin-12. However, induction of cell surface CD1d was impaired in infected Ii(-/-) macrophages, and CD1d-restricted iNKT cells were unable to suppress bacterial replication when they were cocultured with M. tuberculosis-infected Ii(-/-) macrophages. Thus, while the host factor Ii is not essential for the formation of the M. tuberculosis-containing vacuole, its presence is crucial for iNKT cell recognition of infected macrophages.
Authors:
Fenna C M Sillé; Constance Martin; Pushpa Jayaraman; Alissa Rothchild; Sarah Fortune; Gurdyal S Besra; Samuel M Behar; Marianne Boes
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2011-05-16
Journal Detail:
Title:  Infection and immunity     Volume:  79     ISSN:  1098-5522     ISO Abbreviation:  Infect. Immun.     Publication Date:  2011 Aug 
Date Detail:
Created Date:  2011-07-18     Completed Date:  2011-09-13     Revised Date:  2012-02-01    
Medline Journal Info:
Nlm Unique ID:  0246127     Medline TA:  Infect Immun     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3053-63     Citation Subset:  IM    
Affiliation:
Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Antigen Presentation*
Antigens, CD1d / immunology*,  metabolism
Antigens, Differentiation, B-Lymphocyte / genetics,  immunology*,  metabolism
Endosomes / metabolism,  microbiology
Gene Deletion
Histocompatibility Antigens Class II / genetics,  immunology*,  metabolism
Interleukin-12 / metabolism
Killer Cells, Natural / immunology
Macrophages / immunology*,  microbiology*
Mice
Mice, Inbred C57BL
Mice, Knockout
Microbial Viability
Mycobacterium tuberculosis / immunology*,  pathogenicity*
Nitric Oxide / metabolism
Tumor Necrosis Factor-alpha / metabolism
Grant Support
ID/Acronym/Agency:
5 R01 HL080330/HL/NHLBI NIH HHS; R01 HL080312/HL/NHLBI NIH HHS; R01-AR052810/AR/NIAMS NIH HHS
Chemical
Reg. No./Substance:
0/Antigens, CD1d; 0/Antigens, Differentiation, B-Lymphocyte; 0/Histocompatibility Antigens Class II; 0/Tumor Necrosis Factor-alpha; 0/invariant chain; 10102-43-9/Nitric Oxide; 187348-17-0/Interleukin-12

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