title: Alteration of hepatitis A virus (HAV) particles by a soluble form of HAV cellular receptor 1 containing the immunoglobin-and mucin-like regions.
abstract: Hepatitis A virus (HAV) infects African green monkey kidney cells via HAV cellular receptor 1 (havcr-1). The ectodomain of havcr-1 contains an N-terminal cysteine-rich immunoglobin-like region (D1), followed by a mucin-like region that extends D1 well above the cell surface. D1 is required for binding of HAV, and a soluble construct containing D1 fused to the hinge and Fc portions of human immunoglobin G1 (IgG1), D1-Fc, bound and neutralized HAV inefficiently. However, D1-Fc did not alter the virions. To determine whether additional regions of havcr-1 are required to trigger uncoating of HAV, we constructed D1muc-Fc containing D1 and two-thirds of the mucin-like region fused to the Fc and hinge portions of human IgG1. D1muc-Fc neutralized 10 times more HAV than did D1-Fc. Sedimentation analysis in sucrose gradients showed that treatment of HAV with 20 to 200 nM D1muc-Fc disrupted the majority of the virions, whereas treatment with 2 nM D1muc-Fc had no effect on the sedimentation of the particles. Treatment of HAV with 100 nM D1muc-Fc resulted in low-level accumulation of 100- to 125S particles. Negative-stain electron microscopy analysis revealed that the 100- to 125S particles had the characteristics of disrupted virions, such as internal staining and diffuse edges. Quantitative PCR analysis showed that the 100- to 125S particles contained viral RNA. These results indicate that D1 and the mucin-like region of havcr-1 are required to induce conformational changes leading to HAV uncoating.
authors.affiliation: Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA.
authors.forename: Erica
authors.initials: E
authors.lastname: Silberstein
authors.forename: Li
authors.initials: L
authors.lastname: Xing
authors.forename: Willem
authors.initials: W
authors.lastname: van de Beek
authors.forename: Jinhua
authors.initials: J
authors.lastname: Lu
authors.forename: Holland
authors.initials: H
authors.lastname: Cheng
authors.forename: Gerardo G
authors.initials: GG
authors.lastname: Kaplan
mesh_terms: D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D006224:Cricetinae; D017931:DNA Primers; D000072596:Hepatitis A Virus Cellular Receptor 1; D030041:Hepatitis A virus / Q000276:immunology / Q000648:ultrastructure*; D007136:Immunoglobulins / Q000737:chemistry*; D008253:Macaca mulatta; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000502:physiology*; D008854:Microscopy, Electron; D009077:Mucins / Q000737:chemistry*; D009500:Neutralization Tests; D011991:Receptors, Virus / Q000737:chemistry / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014771:Virion / Q000648:ultrastructure*
chemical_list: D017931:DNA Primers; C491143:HAVCR1 protein, human; D000072596:Hepatitis A Virus Cellular Receptor 1; D007136:Immunoglobulins; D008562:Membrane Glycoproteins; D009077:Mucins; D011991:Receptors, Virus