Characterization and partial purification of a macrophage-stimulating factor from Mycoplasma hominis.
OBJECTIVE
Mycoplasma hominis is one of the most common pathogens of the genital tract and is associated with increased production of proinflammatory cytokines in reproductive tissues during preterm labor. The mechanism by which M. hominis, an organism lacking cell walls, increases the production of proinflammatory cytokines is unknown.


METHODS
We characterized and purified a macrophage-activating factor from this organism.


RESULTS
Extraction of whole organisms with Triton-X-114 demonstrated that the activity was primarily associated with the detergent phase. Macrophage-stimulating activity (MSA) of detergent extracts of M. hominis was not inhibited by polymyxin B or heating but was completely abrogated by alkaline hydrolysis and partially reduced by proteinase K digestion. Further experiments that utilized Toll-like receptor (TLR)-2- and TLR-4-transfected cells, revealed that the detergent extracts activate TLR-2 but not TLR-4 signal transduction. Purification of the activity using preparative SDS-PAGE and reverse phase chromatography experiments led to the isolation of a 29-kDa protein.


CONCLUSIONS
These experiments suggest that the MSA of M. hominis is due to a lipophillic factor that interacts with TLR-2 rather than TLR-4 (as does lipopolysaccharide), to increase tumor necrosis factor (TNF)-alpha by macrophages. It is known that TNF-alpha can cause preterm labor and intrauterine fetal death and that it is upregulated in amniotic fluid samples infected with M. hominis.
Peltier
Morgan R
MR
Department of Obstetrics, Gynecology and Reproductive Sciences, University of Medicine and Dentistry-Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA. peltiemr@umdnj.edu
Freeman
Angela J
AJ
Mu
Hong H
HH
Cole
Barry C
BC
D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification*; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D019286:Endopeptidase K / Q000187:drug effects / Q000276:immunology; D006801:Humans; D006868:Hydrolysis; D009175:Mycoplasma Infections / Q000276:immunology; D019535:Mycoplasma hominis / Q000737:chemistry* / Q000187:drug effects / Q000276:immunology*; D017830:Octoxynol; D011092:Polyethylene Glycols / Q000494:pharmacology; D012972:Sodium Hydroxide / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000378:metabolism
D001426:Bacterial Proteins; D014409:Tumor Necrosis Factor-alpha; D011092:Polyethylene Glycols; D012972:Sodium Hydroxide; D017830:Octoxynol; C010615:Nonidet P-40; D019286:Endopeptidase K