Choline Transporter-Like Protein-2: New von Willebrand Factor-Binding Partner Involved in Antibody-Mediated Neutrophil Activation and Transfusion-Related Acute Lung Injury.
OBJECTIVE
In contrast to other antibodies involved in transfusion-related acute lung injury, anti-HNA-3a antibodies are incapable of inducing direct neutrophil activation and seem to interact with endothelial cells (ECs) primarily. In animal studies, anti-HNA-3a-mediated transfusion-related acute lung injury could be precipitated in the absence of neutrophils, but was stronger when neutrophils were present. In a different context the target protein of these antibodies, choline transporter-like protein-2 (CTL-2), was reported to interact with a protein of the inner ear carrying 2 von Willebrand factor (VWF) A-domains. These observations prompted us to investigate whether VWF might be involved in anti-HNA-3a-mediated neutrophil activation, and whether signaling via CD11b/CD18 is involved, as in various other experimental settings.


RESULTS
Cell adhesion demonstrated specific binding of CTL-2 to VWF. Immunoprecipitation analysis of CTL-2/CD11b/CD18 coexpressing cells indicated that anti-HNA-3a colocalizes CTL-2 and CD11b/CD18 when VWF is present. Functional studies revealed that anti-HNA-3a-mediated neutrophil agglutination is an active, protein kinase C-dependent and partially Fc-dependent process. Agglutination and the production of reactive oxygen species seem to require the formation of a trimolecular complex between the target antigen (CTL-2), CD11b/CD18 and VWF. In line with these observations, anti-HNA-3a induced less severe transfusion-related acute lung injury and less neutrophil recruitment to the alveolar space in VWF knockout mice.


CONCLUSIONS
We introduce CTL-2 as a new binding partner for VWF. Interaction of neutrophils with VWF via CTL-2 allows anti-HNA-3a to induce signal transduction via CD11b/CD18, which leads to neutrophil activation and agglutination. In transfusion-related acute lung injury, this mechanism may further aggravate endothelial leakage.
From the Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany (B.B., Y.T., H.B., S.W., U.J.S., S.S.); and Laboratory for Thrombosis Research, KU Leuven Kulak, Kortrijk, Belgium (H.D., S.F.D.M.).
Behnaz
B
Bayat
From the Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany (B.B., Y.T., H.B., S.W., U.J.S., S.S.); and Laboratory for Thrombosis Research, KU Leuven Kulak, Kortrijk, Belgium (H.D., S.F.D.M.).
Yudy
Y
Tjahjono
From the Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany (B.B., Y.T., H.B., S.W., U.J.S., S.S.); and Laboratory for Thrombosis Research, KU Leuven Kulak, Kortrijk, Belgium (H.D., S.F.D.M.).
Heike
H
Berghöfer
From the Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany (B.B., Y.T., H.B., S.W., U.J.S., S.S.); and Laboratory for Thrombosis Research, KU Leuven Kulak, Kortrijk, Belgium (H.D., S.F.D.M.).
Silke
S
Werth
From the Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany (B.B., Y.T., H.B., S.W., U.J.S., S.S.); and Laboratory for Thrombosis Research, KU Leuven Kulak, Kortrijk, Belgium (H.D., S.F.D.M.).
Hans
H
Deckmyn
From the Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany (B.B., Y.T., H.B., S.W., U.J.S., S.S.); and Laboratory for Thrombosis Research, KU Leuven Kulak, Kortrijk, Belgium (H.D., S.F.D.M.).
Simon F
SF
De Meyer
From the Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany (B.B., Y.T., H.B., S.W., U.J.S., S.S.); and Laboratory for Thrombosis Research, KU Leuven Kulak, Kortrijk, Belgium (H.D., S.F.D.M.).
Ulrich J
UJ
Sachs
From the Institute for Clinical Immunology and Transfusion Medicine, Justus Liebig University, Giessen, Germany (B.B., Y.T., H.B., S.W., U.J.S., S.S.); and Laboratory for Thrombosis Research, KU Leuven Kulak, Kortrijk, Belgium (H.D., S.F.D.M.). sentot.santoso@med.uni-giessen.de.
Sentot
S
Santoso
D055371:Acute Lung Injury / Q000276:immunology* / Q000378:metabolism*; D000818:Animals; D039481:CD11b Antigen / Q000378:metabolism; D018821:CD18 Antigens / Q000378:metabolism; D007518:Isoantibodies / Q000276:immunology*; D007519:Isoantigens / Q000276:immunology; D026901:Membrane Transport Proteins / Q000378:metabolism*; D018345:Mice, Knockout; D009504:Neutrophils / Q000276:immunology*; D011485:Protein Binding; D017382:Reactive Oxygen Species / Q000378:metabolism; D065227:Transfusion Reaction; D014841:von Willebrand Factor / Q000378:metabolism*
D039481:CD11b Antigen; D018821:CD18 Antigens; D007518:Isoantibodies; D007519:Isoantigens; D026901:Membrane Transport Proteins; D017382:Reactive Oxygen Species; C571060:SLC44A2 protein, mouse; D014841:von Willebrand Factor
cholin transporter-like protein 2; von Willebrand factor