Reduction in the adherence of Pseudomonas aeruginosa to native cystic fibrosis epithelium with anti-asialoGM1 antibody and neuraminidase inhibition

Abstract

Reduction in the adherence of Pseudomonas aeruginosa to native cystic fibrosis epithelium with anti-asialoGM1 antibody and neuraminidase inhibition. J. Davies, A. Dewar, A. Bush, T. Pitt, D. Gruenert, D.M. Geddes, E.W.F.W. Alton. #ERS Journals Ltd 1999. ABSTRACT: The high incidence of colonization of the cystic fibrosis (CF) airway with Pseudomonas aeruginosa has been attributed to several mechanisms including increased numbers of asialoglycolipid receptors, which may be further increased by exposure to the bacterial exoproduct, neuraminidase. This study examined whether the adherence of P. aeruginosa to fresh CF respiratory epithelial cells can be reduced in vitro by anti-asialoGM1 (anti-aGM1) antibody, neuraminidase inhibition, or the use of asialoGM1 tetrasaccharide as a competitive inhibitor.CF nasal epithelial cells were incubated with a nonmucoid strain of P. aeruginosa, in the presence or absence of a polyclonal anti-aGM1 antibody, the neuraminidase inhibitor 2,3-dehydro-2-deoxy-N-acetyl-neuraminic acid (DANA), or the tetrasaccharide moiety of aGM1. Adherence of bacteria to the apical surface of ciliated epithelial cells was quantified using scanning electron microscopy. Incubation of the cells with bacteria in the presence of either anti-aGM1 antibody or DANA significantly reduced bacterial adherence by 51(7)%, (p<0.01), and 34(9)%, (p<0.01), respectively. In contrast, no significant effect on P. aeruginosa binding was seen in the presence of aGM1 tetrasaccharide.The data are consistent with previous studies on cultured cells, and suggest that the in vivo effects of such interventions should be explored as potential mechanisms to reduce Pseudomonas aeruginosa colonization in cystic fibrosis. Eur Respir J 1999; 13: 565±570.

Lack of Adherence of Clinical Isolates of Pseudomonas aeruginosa to Asialo-GM 1 on Epithelial Cells

“…In addition, some investigators have reported that asialo-GM 1 is a receptor for both pili and lipopolysaccharide (LPS) of P. aeruginosa present on murine and bovine corneal epithelial cells (16,20,47); others have disputed whether asialo-GM 1 is expressed in the human cornea (52). Some of these studies confirmed that asialo-GM 1 is a receptor for P. aeruginosa binding by using purified glycolipid to inhibit binding (24,47) or commercially prepared antisera to this antigen (7,9,10,20,24). Finally, a role has been proposed for a possible neuraminidase in generating asialo-GM 1 tetrasaccharide from the parental sialylated GM 1 molecule (3,9), although to date the only evidence for a gene that encodes a P. aeruginosa neuraminidase is the recent identification of a DNA sequence in P. aeruginosa PAO1 that has some homology to other bacterial neuraminidases (GenBank accession no.…”

“…In the Singh et al study, monosialoganglioside (GM 1 ), which is not considered a major receptor for P. aeruginosa, had efficacy comparable to that of asialo-GM 1 , whereas in the Imundo et al study GM 1 was not an effective inhibitor of P. aeruginosa binding to cells (24). Also, Davies et al (9) could not inhibit binding of P. aeruginosa to CF epithelial cells with the asialo-GM 1 tetrasaccharide.…”

“…Although numerous investigators have found these antibodies to be effective at inhibiting the binding of P. aeruginosa to cells (2,7,9,10,22), essentially none of the studies confirmed the specificity of the antibodies by blocking the biologic activity of the antibodies with appropriate adsorbing or inhibiting reagents to demonstrate the specificity of the antibodies to asialo-GM 1 . Of even greater concern is that these polyclonal antibodies are raised in rabbits to essentially a self-antigen purified from bovine tissues emulsified in methylated bovine serum albumin (BSA) and complete Freund's adjuvant.…”

“…For Pseudomonas aeruginosa, numerous studies have implicated flagella and pili as bacterial adhesins that bind specifically to terminal or internal N-acetylgalactosamine (GalNAc) residues that are linked beta-1-4 to galactose (Gal) residues unsubstituted with sialyl residues (30). Such structures are found in the gangliotetraosylceramide (asialo-GM 1 ) receptor on host cells (2,7,9,10,24). The number of asialo-GM 1 receptors is reported to be increased on respiratory epithelial cells from patients with cystic fibrosis (CF) who are homozygous for the ⌬F508 allele of the CF transmembrane conductance regulator (CFTR) (24,39,51).…”

“…Few of the studies used clinical isolates of P. aeruginosa (30); most used well-characterized laboratory strains such as PAO1, PAK, ATCC 19660, and PA103 (7,9,10,21,24). Only two studies presented evidence that purified asialo-GM 1 ganglioside, or the purified tetrasaccharide, could inhibit the adherence of P. aeruginosa to cells (24,47).…”