Characteristics and biological variations of M-ficolin, a pattern recognition molecule, in plasma.
The three human ficolins, H-ficolin, L-ficolin and M-ficolin, are pattern recognition molecules of the innate immune system. All three ficolins can activate the lectin pathway of the complement system after binding to pathogens. H- and L-ficolin are serum proteins with an average concentration of 18 and 3 microg/ml, respectively. M-ficolin has been described as a membrane-associated pattern recognition receptor of monocytes, being also present in granulocytes; recently, minuscule amounts of M-ficolin have been found in serum, too. No assay specific for M-ficolin has yet been described and biological variations are unknown. We have raised specific monoclonal anti-human M-ficolin antibodies and have developed a quantitative assay for M-ficolin. M-ficolin elutes as a large, 900-kDa protein upon gel permeation chromatography of serum. Analysis of M-ficolin levels in serum samples of 350 blood donors reveals a mean concentration of 1.07 microg/ml, ranging from 0.28 to 4.05 microg/ml. Analyses of consecutive acute phase serum samples from major surgery patients indicated a complex response. Ontogeny was investigated through cord blood samples from healthy full-term babies, which showed adult levels, with sequential samples showing no increase from birth to 1 year of age. We suggest that M-ficolin should also be considered as a humoral pattern recognition molecule.
Wittenborn
Thomas
T
Department of Medical Microbiology and Immunology, University of Aarhus, Aarhus, Denmark.
Thiel
Steffen
S
Jensen
Lisbeth
L
Nielsen
Hans J
HJ
Jensenius
Jens C
JC
D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001798:Blood Proteins / Q000737:chemistry / Q000302:isolation & purification; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D037102:Lectins / Q000097:blood / Q000737:chemistry / Q000302:isolation & purification; D051379:Mice; D008807:Mice, Inbred BALB C; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D051192:Receptors, Pattern Recognition / Q000737:chemistry / Q000378:metabolism; D000097604:Ficolins
D000911:Antibodies, Monoclonal; D001798:Blood Proteins; D037102:Lectins; D051192:Receptors, Pattern Recognition; D000097604:Ficolins