A lectin microarray study of glycoantigens in neonatal porcine islet-like cell clusters

Background: Besides α-Gal expression, the differences of glycosylation and antigenicity between adult pig islets (APIs) and neonatal porcine islet-like cell clusters (NPCCs) are altogether unclear. In this study, lectin microarray analyses of NPCCs were performed and the results compared with the corresponding values for wild-type APIs and NPCCs from α-Gal transferase knockout (GalT-KO) pig. Methods: NPCCs were isolated from 1-3-d-old neonatal wild-type pigs and cultured for 1 d, 5 d, and 9 d, using a previously described technique. Alternatively, the isoration of APIs were isolated based on the method for human islets. Results: In a comparison between NPCCs and APIs, all of the NPCCs showed higher signals for Sambucus nigra, Sambucus sieboldiana, and Trichosanthes japonica I and the binding of α2,6 sialc acid, whereas the APIs showed stronger signals for Lotus tetragonolobus, Aleuria aurantia, Narcissus pseudonarcissus, and Galanthus nivalis, suggesting that APIs contain high levels of high-mannose forms. Among the NPCCs, NPCC (day1) appeared to be richer than the others in Lotus tetragonolobus, Narcissus pseudonarcissus, Galanthus nivalis, and Urtica dioica, implying the presence of high-mannose forms. However, as a whole, the signals for many lectins for NPCCs were very similar. The NPCCs from a GalT-KO pig indicated not only the downregulation of α-Gal expression but α-GalNAc as well, and α2-6 sialic acid was upregulated. Conclusions: The results reported herein contain useful information for the future production of immunomodified pigs with less antigenicity than GalT-KO pigs toward clinical applications of NPCCs.