Arch Virol (2002) 147: 2047–2056
The role of feline aminopeptidase N as a receptor
for infectious bronchitis virus
, G. T. Pharr, and C. Wang
Department of Basic Sciences, College of Veterinary Medicine, Mississippi State
University, Mississippi State, U.S.A.
Received March 26, 2002; accepted July 11, 2002
Published online September 18, 2002
Summary. Feline aminopeptidase N (fAPN) has been shown to serve as a
receptor for feline, canine, porcine and human coronaviruses. Our objective was
to determine if fAPN can serve as a receptor for infectious bronchitis virus (IBV).
Feline kidney cells that express fAPN and hamster kidney ﬁbroblasts that do not
express fAPN were inoculated with IBV and monitored for replication by indirect
ﬂuorescent assay and confocal microscopy and in chicken embryonated eggs.
The results showed that the feline cells were permissive to IBV but the hamster
cells were not. The hamster cells became permissive to IBV after transfection
with a fAPN cDNA suggesting that the feline APN molecule plays a role in IBV
Members of the family Coronaviridae infect a wide range of hosts and have been
classiﬁed into three groups. One major group (group I) was recently shown to use
aminopeptidase N (APN) as its cell surface receptor [7, 9, 10, 11, 16, 21–23, 28,
43]. Aminopeptidase N, also called CD13 in humans , is a zinc metallopro-
tease. It is a 150-kDa glycoprotein with zinc located in its globular region that is
believed to be the active enzymatic site playing a major role in the cleaving of
peptides[1,2, 12, 15, 33].APNisexpressedontheplasmamembranesof granulo-
cytes [2, 36], lymphocytes and monocytes [26, 30, 31, 35]. It is also expressed on
Presentaddress: DepartmentofMicrobiology andImmunology,CornellUniversityDuck
Research Laboratory, P.O. Box 217, Eastport, NY 11941-0217, U.S.A.