Porcine endothelium activated by anti-alpha-GAL antibody binding mediates increased human neutrophil adhesion under flow.
BACKGROUND
Neutrophils participate in acute vascular rejection (AVR) of organ xenografts. Induced antibodies (Abs), including anti-Galalpha1,3Gal (alpha-Gal) Abs, have been suggested to cause AVR. We investigated the adhesion of naive human neutrophils to porcine aortic endothelial cells (PAECs) stimulated with anti-alpha-Gal Abs under conditions of flow. In addition, the ability of human neutrophils to adhere to human and porcine endothelium under static and flow conditions was evaluated.


RESULTS
In a flow-adhesion assay, a significant increase in adhesion of human neutrophils to PAECs, but not to human aortic endothelial cells (HAECs), was detected 6 hours after anti-alpha-Gal Ab-binding. After Ab stimulation, PAECs expressed CD62E and increased levels of CD106, indicating an activated endothelial cell (EC) phenotype. In a migration assay, supernatants from Ab-stimulated PAECs induced migration of human neutrophils, which was partially blocked by anti-porcine (p) interleukin (IL)-8 Abs and an antagonist to platelet-activating factor (PAF). In static and flow-adhesion assays, no difference in adhesion of human neutrophils to unstimulated or tumor necrosis factor (TNF)-alpha-stimulated HAECs and PAECs could be detected.


CONCLUSIONS
Our data suggest that anti-alpha-Gal Abs play an important role in the initiation of AVR by mediating adhesion and recruitment of neutrophils within an organ xenograft. In contrast with previous investigations, our data argues against a differential recognition of PAECs and HAECs by human neutrophils. Thus, to prevent AVR and accomplish long-term xenograft survival, it will be important to remove anti-alpha-Gal Abs before and after pig-to-human transplantation.
Ehrnfelt
Cecilia
C
Division of Clinical Immunology, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden. cecilia.ehrnfelt@labmed.ki.se.
Serrander
Lena
L
Holgersson
Jan
J
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D001011:Aorta / Q000166:cytology / Q000276:immunology*; D001775:Blood Circulation / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement; D002478:Cells, Cultured; D004187:Disaccharides / Q000276:immunology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D016209:Interleukin-8 / Q000008:administration & dosage; D009504:Neutrophils / Q000502:physiology*; D011994:Recombinant Proteins / Q000008:administration & dosage; D013552:Swine
D000906:Antibodies; D004187:Disaccharides; D016209:Interleukin-8; D011994:Recombinant Proteins; C055075:galactosyl-(1-3)galactose