Lipopolysaccharide-binding protein is produced in the epididymis and associated with spermatozoa and prostasomes.
Lipopolysaccharide-binding protein (LBP) is an acute phase protein known to play a central role in the defense against Gram-negative bacteria. It binds lipopolysaccharides of Gram-negative bacteria and, after binding to CD14, the complex signals through Toll-like receptor (TLR)-4, eliciting host-defense responses, such as cytokine production, in inflammatory cells. The present study demonstrates constitutive expression of the gene encoding lipopolysaccharide-binding protein in the epithelium of the human epididymis by in situ hybridization. Using immunohistochemistry lipopolysaccharide-binding protein was shown to be present in the same cells and also attached to the heads and tails of spermatozoa. Cell-free seminal plasma, lysed spermatozoa and lysed prostasomes were subjected to Western blot; all showed immunoreactive bands corresponding to the size of lipopolysaccharide-binding protein. Gel filtration demonstrated that lipopolysaccharide-binding protein colocalizes with prostasomes. The concentration of lipopolysacharide-binding protein in seminal plasma was 127+/-42ng/mL (mean+/-S.D.; range 73-215ng/mL). Taken together, our results suggest roles for lipopolysaccharide-binding protein during human reproduction.
Malm
Johan
J
Department of Clinical Chemistry, Malmö University Hospital, SE-205 02 Malmö, Sweden. johan.malm@klkemi.mas.lu.se
Nordahl
Emma Andersson
EA
Bjartell
Anders
A
Sørensen
Ole E
OE
Frohm
Birgitta
B
Dentener
Mieke A
MA
Egesten
Arne
A
D000209:Acute-Phase Proteins / Q000032:analysis* / Q000096:biosynthesis* / Q000235:genetics; D002352:Carrier Proteins / Q000032:analysis* / Q000096:biosynthesis* / Q000235:genetics; D004822:Epididymis / Q000166:cytology / Q000378:metabolism*; D004847:Epithelial Cells / Q000276:immunology; D015870:Gene Expression; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000096:biosynthesis* / Q000235:genetics; D011467:Prostate / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D022142:Secretory Vesicles / Q000737:chemistry; D012661:Semen / Q000276:immunology; D013077:Sperm Head / Q000276:immunology; D013082:Sperm Tail / Q000276:immunology; D013094:Spermatozoa / Q000737:chemistry* / Q000276:immunology; D000099231:Lipopolysaccharide-Binding Protein
D000209:Acute-Phase Proteins; D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D000099231:Lipopolysaccharide-Binding Protein