Collectin 11 (CL-11, CL-K1) is a MASP-1/3-associated plasma collectin with microbial-binding activity.
Collectins play important roles in the innate immune defense against microorganisms. Recently, a new collectin, collectin 11 (CL-11 or CL-K1), was identified via database searches. In present work, we characterize the structural and functional properties of CL-11. Under nonreducing conditions, in gel permeation chromatography recombinant CL-11 forms disulfide-linked oligomers of 100 and 200 kDa. A mAb-based ELISA estimates the concentration of CL-11 in plasma to be 2.1 μg/ml, and the presence of CL-11 in plasma was further verified by Western blotting and mass spectrometry. Mannan-binding lectin-associated serine protease 1 (MASP-1) copurified with CL-11 and the interaction in plasma with MASP-1 and/or MASP-3 was further demonstrated using ELISA. We identified the adrenal glands, the kidneys, and the liver as primary sites of expression. CL-11 lectin activity was demonstrated by ELISA and showed that CL-11 has preference for l-fucose and d-mannose. We finally show that CL-11 binds to intact bacteria, fungi, and viruses and that CL-11 decreases influenza A virus infectivity and forms complexes with DNA. On the basis of the significant concentration of CL-11 in circulation and CL-11's interaction with various microorganisms and MASP-1 and/or MASP-3, it is conceivable that CL-11 plays a role in activation of the complement system and in the defense against invading microorganisms.
Hansen
Soren
S
Department of Cancer and Inflammation Research, University of Southern Denmark, Odense, Denmark. SHansen@health.sdu.dk
Selman
Lana
L
Palaniyar
Nades
N
Ziegler
Karel
K
Brandt
Jette
J
Kliem
Anette
A
Jonasson
Maiken
M
Skjoedt
Mikkel-Ole
MO
Nielsen
Ole
O
Hartshorn
Kevan
K
Jørgensen
Thomas J D
TJ
Skjødt
Karsten
K
Holmskov
Uffe
U
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002850:Chromatography, Gel; D037222:Collectins / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007113:Immunity, Innate; D007150:Immunohistochemistry; D050606:Mannose-Binding Protein-Associated Serine Proteases; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction
C518521:Colec11 protein, human; D037222:Collectins; C084067:MASP1 protein, human; D050606:Mannose-Binding Protein-Associated Serine Proteases