N-GLYCOSYLATED PROTEINS ARE INVOLVED IN EFFICIENT INTERNALIZATION OF KLEBSIELLA-PNEUMONIAE BY CULTURED HUMAN EPITHELIAL-CELLS

Klebsiella pneumoniae obtained from patients with urinary tract infect ions is able to invade cultured human epithelial cells, The internaliz ation process is dependent upon both microfilaments and microtubules. To better understand the interaction of these invasive bacteria with t he host cell receptor(s), bladder, lung, and ileocecal epithelial cell s were infected with K, pneumoniae in the presence of various lectins possessing multiple glycan specificities, It was found that the N-acet ylglucosamine (GlcNAc)-specific lectins concanavalin A, Datura stramon ium agglutinin, and wheat germ agglutinin significantly inhibited the invasion of K, pneumoniae into these cells but did not interfere with the internalization of an invasive strain of Salmonella typhimurium. C onversely, internalization of K. pneumoniae but not S, typhimurium was also significantly inhibited when the bacteria were pretreated with G lcNAc or chitin hydrolysate, a GlcNAc polymer, prior to the gentamicin invasion assay, Other carbohydrates such as glucose, galactose, manno se, fucose, and N-acetylneuraminic acid had no inhibitory effects an K , pneumoniae uptake, Furthermore, internalization of K, pneumoniae but not S. typhimurium by HCT8 cells was also significantly inhibited whe n eukaryotic protein glycosylation was interrupted by tunicamycin or w hen host N-linked surface glycans were removed by pretreatment,vith N- glycosidase F. These studies suggest that a N-glycosylated protein rec eptor is involved in the internalization of K, pneumoniae by human epi thelial cells in vitro, The results also indicate that internal GlcNAc residues might be a carbohydrate component of the receptor.