Serum concentration and interaction properties of MBL/ficolin associated protein-1

TY - JOUR

T1 - Serum concentration and interaction properties of MBL/ficolin associated protein-1

AU - Skjoedt, Mikkel-ole

AU - Hummelshoj, Tina

AU - Palarasah, Yaseelan

AU - Hein, Estrid

AU - Munthe-fog, Lea

AU - Koch, Claus

AU - Skjodt, Karsten

AU - Garred, Peter

PY - 2011/5/1

Y1 - 2011/5/1

N2 - Recently, a novel protein named MBL/ficolin associated protein-1 (MAP-1) derived from the MASP1 gene through differential splicing was identified. In the present study, we established biochemical characteristics, determined the serum level and assessed the interactions between the lectin complement pathway (LCP) recognition molecules and MAP-1. We expressed recombinant MAP-1 in CHO DG44 cells, developed a quantitative ELISA assay based on a MAP-1 specific monoclonal capture antibody and measured the serum levels in 100 Danish blood donors. In addition we assessed the association properties between MAP-1 and Ficolin-2, -3 and MBL in serum using ELISA and density gradient ultra centrifugation. When recombinant MAP-1 was subjected to N-glycosidase F treatment the molecular mass decreased from ∼45. kDa to ∼40. kDa equivalent with the calculated molecular mass from the deduced amino acid sequence without the signal peptide. We found that serum MAP-1 was very stable when subjected to repeated freeze and thaw cycles. The mean serum concentration of MAP-1 was found to be 240. ng/ml (range: 115-466. ng/ml). MAP-1 was predominantly found in complex with Ficolin-3 and to a lesser degree with Ficolin-2 and MBL and by use of density gradient ultra centrifugation we could show that the major part of serum MAP-1 circulates in complex with the LCP molecules. In conclusion, these results show that MAP-1 is a highly stable glycosylated human serum protein found in complex with Ficolin-3, Ficolin-2 and MBL.

AB - Recently, a novel protein named MBL/ficolin associated protein-1 (MAP-1) derived from the MASP1 gene through differential splicing was identified. In the present study, we established biochemical characteristics, determined the serum level and assessed the interactions between the lectin complement pathway (LCP) recognition molecules and MAP-1. We expressed recombinant MAP-1 in CHO DG44 cells, developed a quantitative ELISA assay based on a MAP-1 specific monoclonal capture antibody and measured the serum levels in 100 Danish blood donors. In addition we assessed the association properties between MAP-1 and Ficolin-2, -3 and MBL in serum using ELISA and density gradient ultra centrifugation. When recombinant MAP-1 was subjected to N-glycosidase F treatment the molecular mass decreased from ∼45. kDa to ∼40. kDa equivalent with the calculated molecular mass from the deduced amino acid sequence without the signal peptide. We found that serum MAP-1 was very stable when subjected to repeated freeze and thaw cycles. The mean serum concentration of MAP-1 was found to be 240. ng/ml (range: 115-466. ng/ml). MAP-1 was predominantly found in complex with Ficolin-3 and to a lesser degree with Ficolin-2 and MBL and by use of density gradient ultra centrifugation we could show that the major part of serum MAP-1 circulates in complex with the LCP molecules. In conclusion, these results show that MAP-1 is a highly stable glycosylated human serum protein found in complex with Ficolin-3, Ficolin-2 and MBL.

U2 - 10.1016/j.imbio.2010.09.011

DO - 10.1016/j.imbio.2010.09.011

M3 - Journal article

SN - 0171-2985

VL - 216

SP - 625

EP - 632

JO - Immunobiology

JF - Immunobiology

IS - 5

ER -