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

Analysis of modified Sia in saliva, mucus, and on erythrocytes. It has been previously reported that human colonic mucin is highly enriched in 9-O-Ac Sia, which may 200 regulate the activity of some sialidases and Sia transporters of the gut microflora (11, 32, 47, 48) . Strong staining for 9-O-Ac in human respiratory tissues, and also within the submucosal glands of human respiratory tissue have also been reported, indicating that mucus from these glands could be enriched in O-acetylated Sia (47, 48) . To determine if human respiratory mucus was enriched in 7,9-O-and 9-O-Ac, secreted mucus from primary normal human bronchial 205 epithelial cells (NHBE) as well as conditioned media from human alveolar basal epithelial adenocarcinoma A549 cells, were analyzed by HPLC to determine Sia composition. We found that the secreted proteins in mucus from NHBE cells and A549 cells conditioned media contained primarily unmodified Neu5Ac with ~1-2% of 9-O-Ac and no detectable levels of 7,9-O-Ac (Table 1) . This indicates that secreted mucus from these respiratory cells in culture are 210 All rights reserved. No reuse allowed without permission.