Characterization of factor H-related cell membrane molecules expressed by human B lymphocytes and neutrophil granulocytes

The human factor H protein family comprises six plasma glycoproteins. Earlier we described a membranal factor H-related (mFHR) molecule that is expressed by human B lymphoblastoid cell lines and exerts cofactor activity. In our present study we screened human blood cells for the presence of mFHR pro...

Full description

Saved in:
Bibliographic Details
Published in:Immunology letters 2001-05, Vol.77 (1), p.55-62
Main Authors: Józsi, Mihály, Kapus, Attila, Kerekes, Krisztina, Kármán, József, Bajtay, Zsuzsa, Zipfel, Peter F, Erdei, Anna
Format: Article
Language:English
Subjects:
B lymphocytes
B-Lymphocytes - cytology
B-Lymphocytes - metabolism
Cell Membrane - metabolism
Cells, Cultured
complement factor H
Complement Factor H - biosynthesis
Down-Regulation
Factor H-related
Heparin - metabolism
Heparin binding
Humans
Isoenzymes - metabolism
Lymphocyte Activation
Neutrophils
Neutrophils - cytology
Neutrophils - metabolism
Phosphatidylinositol Diacylglycerol-Lyase
Phospholipase C gamma
Type C Phospholipases - metabolism
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The human factor H protein family comprises six plasma glycoproteins. Earlier we described a membranal factor H-related (mFHR) molecule that is expressed by human B lymphoblastoid cell lines and exerts cofactor activity. In our present study we screened human blood cells for the presence of mFHR proteins and further characterized these molecules. By cytofluorimetry it is shown that the factor H-specific rabbit antiserum reacts strongly with B cells and neutrophil granulocytes, but not with T cells and monocytes. On B lymphocytes mFHR is shown to be down-regulated upon activation of the cells via sIg. In experiments studying which short consensus repeat (SCR) domains are part of the cell membrane proteins we found that antibodies raised against SCRs 1–4, 19–20 and FHR-3 bound to neutrophils but not to B cells. While mFHRs derived both from B cells and granulocytes are shown to bind heparin, their size and structure are different as revealed by Western blotting. A further characteristic of the granulocyte-derived mFHR is its sensitivity to the PI-specific PLCγ enzyme. These data demonstrate the existence of new members of the FHR protein family, as two distinct, membranal forms are identified. Based on the differences, the B cell derived molecule is termed mFHR-1 and the neutrophil derived protein mFHR-2.
ISSN:0165-2478
1879-0542
DOI:10.1016/S0165-2478(01)00194-8