Human oviductal stromal fibroblasts, but not oviductal epithelial cells, express Toll-like receptor 4: the site-specific mucosal immunity of the human fallopian tube against bacterial infection.
OBJECTIVE
To evaluate the site-specific immunoregulatory mechanisms against bacterial infection in the human fallopian tubes.


METHODS
We investigated the effects of lipopolysaccharide (LPS) on the production of CXC chemokines by cultured oviductal epithelial cells (OEC) and oviductal stromal fibroblasts (OSF). The expression of Toll-like receptor (TLR) 4 and CD14 protein in OEC and OSF were evaluated. The phosphorylation of the inhibitor kappaB-alpha (IkappaB-alpha) protein after LPS stimulation was also examined.


RESULTS
Lipopolysaccharide stimulated the secretion of granulocyte chemotactic protein-2, growth-regulated oncogene-alpha, and epithelial neutrophil activating peptide-78 by OSF, but not by OEC. The phosphorylation of the IkappaB-alpha protein was not detected in OEC after stimulation by LPS, whereas IkappaB-alpha phosphorylation was observed in OSF after stimulation by LPS. The expression of the TLR4 protein and mRNA was detected only in OSF but not in OEC. The expression of CD14 was not detected in either OEC or OSF.


CONCLUSIONS
These results suggest that epithelial cells and fibroblasts in the human fallopian tube have evolved a unique, site-specific mechanism for recognizing Gram-negative pathogens. The lack of TLR4 in OEC may be important for avoiding a state of unnecessary inflammation that could disrupt the epithelial barrier and cause irreversible tubal scarring.
Itoh
Hiroko
H
Department of Obstetrics and Gynecology, Faculty of Medicine, Oita University, Japan.
Nasu
Kaei
K
Nishida
Masakazu
M
Matsumoto
Harunobu
H
Yuge
Akitoshi
A
Narahara
Hisashi
H
D002478:Cells, Cultured; D019743:Chemokines, CXC / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D005187:Fallopian Tubes / Q000166:cytology*; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D018928:Immunity, Mucosal / Q000276:immunology; D009092:Mucous Membrane / Q000187:drug effects / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000166:cytology*; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis* / Q000235:genetics
D019743:Chemokines, CXC; D011135:Polysaccharides, Bacterial; D051197:Toll-Like Receptor 4