title: Chimeric feline coronaviruses that encode type II spike protein on type I genetic background display accelerated viral growth and altered receptor usage.
abstract: Persistent infection of domestic cats with feline coronaviruses (FCoVs) can lead to a highly lethal, immunopathological disease termed feline infectious peritonitis (FIP). Interestingly, there are two serotypes, type I and type II FCoVs, that can cause both persistent infection and FIP, even though their main determinant of host cell tropism, the spike (S) protein, is of different phylogeny and displays limited sequence identity. In cell culture, however, there are apparent differences. Type II FCoVs can be propagated to high titers by employing feline aminopeptidase N (fAPN) as a cellular receptor, whereas the propagation of type I FCoVs is usually difficult, and the involvement of fAPN as a receptor is controversial. In this study we have analyzed the phenotypes of recombinant FCoVs that are based on the genetic background of type I FCoV strain Black but encode the type II FCoV strain 79-1146 S protein. Our data demonstrate that recombinant FCoVs expressing a type II FCoV S protein acquire the ability to efficiently use fAPN for host cell entry and corroborate the notion that type I FCoVs use another main host cell receptor. We also observed that recombinant FCoVs display a large-plaque phenotype and, unexpectedly, accelerated growth kinetics indistinguishable from that of type II FCoV strain 79-1146. Thus, the main phenotypic differences for type I and type II FCoVs in cell culture, namely, the growth kinetics and the efficient usage of fAPN as a cellular receptor, can be attributed solely to the FCoV S protein.
authors.affiliation: Institut für Virologie, Justus Liebig Universität Giessen, Giessen, Germany.
authors.forename: Gergely
authors.initials: G
authors.lastname: Tekes
authors.forename: Regina
authors.initials: R
authors.lastname: Hofmann-Lehmann
authors.forename: Barbara
authors.initials: B
authors.lastname: Bank-Wolf
authors.forename: Reinhard
authors.initials: R
authors.lastname: Maier
authors.forename: Heinz-Jürgen
authors.initials: HJ
authors.lastname: Thiel
authors.forename: Volker
authors.initials: V
authors.lastname: Thiel
mesh_terms: D000818:Animals; D002415:Cats; D002460:Cell Line; D046528:Chimerism; D016765:Coronavirus, Feline / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D006224:Cricetinae; D005434:Flow Cytometry; D005814:Genes, Viral; D008562:Membrane Glycoproteins / Q000235:genetics*; D011991:Receptors, Virus / Q000502:physiology*; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins / Q000235:genetics*
chemical_list: D008562:Membrane Glycoproteins; D011991:Receptors, Virus; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus