Polymorphisms of the hepatitis A virus cellular receptor 1 in African green monkey kidney cells result in antigenic variants that do not react with protective monoclonal antibody 190/4.
Monoclonal antibody (MAb) 190/4 blocks binding of hepatitis A virus (HAV) to the HAV cellular receptor 1 (havcr-1) and protects African green monkey kidney (AGMK) clone GL37 cells (GL37 cells) against HAV infection. BS-C-1 and CV-1 cells, two widely used AGMK cell lines, did not react with MAb 190/4 but expressed havcr-1, as judged by Western blot analysis. The cDNA coding for havcr-1 was amplified from BS-C-1 and CV-1 total cellular RNA by reverse transcription-PCR. Alignment of the amino acid sequences inferred from the cDNA nucleotide sequences showed that BS-C-1 and CV-1 havcr-1 differed from GL37 havcr-1 by having two substitutions in the Cys-rich region, N48H and K108Q, and 10 to 11 additional substitutions plus the insertion of 18 to 22 amino acids in the mucin-like region. Studies with chimeras of GL37 havcr-1 and BS-C-1 havcr-1 showed that the K108Q substitution was responsible for the lack of reaction of MAb 190/4 with BS-C-1 and CV-1 cells. Binding studies indicated that HAV bound to dog cell transfectants expressing the BS-C-1 havcr-1 as well as the GL37/BS-C-1 havcr-1 chimeras. These results indicate that antigenic variants of havcr-1 are expressed in AGMK cells and that binding of HAV to these havcr-1 variants tolerates changes in protective epitope 190/4.
Feigelstock
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Laboratory of Hepatitis Viruses, Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA.
Thompson
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P
Mattoo
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Kaplan
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GG
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D004285:Dogs; D000939:Epitopes; D006507:Hepatovirus / Q000276:immunology*; D007668:Kidney / Q000821:virology; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D011991:Receptors, Virus / Q000235:genetics*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D011991:Receptors, Virus