The effects of modified sialic acids on mucus and erythrocytes on influenza A virus HA and NA functions

Karen N. Barnard; Brynn K. Alford-Lawrence; David W. Buchholz; Brian R. Wasik; Justin R. LaClair; Hai Yu; Rebekah Honce; Stefan Ruhl; Petar Pajic; Erin K. Daugherity; Xi Chen; Stacey L. Schultz-Cherry; Hector C. Aguilar; Ajit Varki; Colin R. Parrish

The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/800300 doi: bioRxiv preprint human IgG1 Fc (HA-Fc) to synthetic, biotinylated α2-6 linked sialosides of Neu5Ac, Neu5Ac9NAc, and Neu5Gc (60). Neu5Ac9NAc was used instead of 9-O-acetyl Neu5Ac 290 (Neu5,9Ac 2 ) due to the increased stability of the 9-N-Ac group (61, 62 Aichi/1968 H3 HA-Fcs had decreased binding to Neu5Gc and Neu5Ac9NAc (Fig. 7A) . The addition of the N-acetyl group at C9 blocked most binding, while Neu5Gc showed only a low level of binding. We saw the same binding dynamics for other H1 and H3 HA-Fc, but the SNA lectin, which recognizes α2-6-linked Sia, bound equally well to Neu5Ac and Neu5Gc, but not to Neu5Ac9NAc (Fig. 7B) . This shows that the presence of O-(and in this case N-) acetyl 300 modifications can inhibit many Sia-binding proteins. Sia in sera have long been known to bind to influenza viruses, so that sera are often treated with neuraminidase as a "receptor destroying enzyme" prior to use in serological tests All rights reserved. No reuse allowed without permission.