Mechanisms of neutralization of influenza virus in tracheal epithelial and BHK cells vary according to IgG concentration.
The interaction of IgG-neutralized type A influenza virus with differentiated epithelial cells of mouse trachea, BHK cells, and chicken erythrocytes was studied using three mouse monoclonal antibodies (IgG2a) each directed against a different antigenic site on the hemagglutinin. At high HIU:HAU ratios virus was neutralized greater than 99%, monodisperse, and attached to tracheal epithelial and BHK cells in normal amounts. The majority (70-80%) of neutralized virus failed to attach to erythrocytes. At low HIU:HAU ratios the virus was aggregated by each of the antibodies, and attachment to tracheal epithelial and BHK cells was inhibited by up to 75%. Combined aggregation and inhibition of attachment could theoretically account for up to 96% loss of infectivity but this corresponded with the observed degree of neutralization with only one of the antibodies. With increasing antibody:virus ratios, aggregation and inhibition of attachment contributed ever diminishingly to the observed neutralization and eventually not at all. Both neutralized and infectious virus attached to neuraminidase-sensitive receptors. After attachment neutralized virus became increasingly resistant to removal by neuraminidase suggesting that it had been internalized by the cell.
Outlaw
M C
MC
Department of Biological Sciences, University of Warwick, Coventry, United Kingdom.
Armstrong
S J
SJ
Dimmock
N J
NJ
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000943:Antigens, Differentiation; D002478:Cells, Cultured; D002642:Chick Embryo; D006224:Cricetinae; D004848:Epithelium / Q000382:microbiology; D007074:Immunoglobulin G / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D009439:Neuraminidase / Q000494:pharmacology; D009500:Neutralization Tests; D009975:Orthomyxoviridae / Q000276:immunology*; D011961:Receptors, Fc / Q000187:drug effects; D017452:Receptors, IgG; D011991:Receptors, Virus / Q000187:drug effects / Q000276:immunology*; D014132:Trachea / Q000382:microbiology*
D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D007074:Immunoglobulin G; D011961:Receptors, Fc; D017452:Receptors, IgG; D011991:Receptors, Virus; D009439:Neuraminidase