Arch Virol (2000) 145: 2335–2349
Antibody responses to respiratory coronavirus infections
of cattle during shipping fever pathogenesis
X. Q. Lin
, K. L. O’Reilly
, J. Storz
, C. W. Purdy
, and R. W. Loan
Department of Veterinary Microbiology and Parasitology, School of Veterinary Medicine,
Louisiana State University, Baton Rouge, Louisiana U.S.A.
Conservation and Production Research Laboratory, USDA, ARS, Bushland, Texas, U.S.A.
Department of Veterinary Pathobiology, Texas A&M University, College Station,
Accepted May 11, 2000
Summary. Antibody responses against respiratory bovine coronavirus (RBCV)
infections were monitored in cattle from the onset of a naturally occurring severe
shipping fever (SF) epizootic to complete recovery of affected cattle or fatal out-
comes. The infection with RBCV was detected in nasal secretions of 86 cattle, and
81 of them developed acute respiratory tract disease, including fatal pneumonia.
Cattle nasally shedding RBCV at the beginning of the epizootic experienced char-
acteristic primary immune responses with speciﬁc antibodies for hemagglutinin-
esterase (HE) and spike (S) glycoproteins. Virus shedding in nasal secretions of
the majority of the cattle ceased between days 7 and 14 with the appearance of
HE- and S-speciﬁc antibodies. Nasal samples and lung tissues from 9 of the 10
fatal cases had high titers of RBCV, but these cattle had only IgM responses to
RBCV infections. Cattle remaining negative in RBCV isolation tests entered this
epizootic with antibodies against HE and S. Protection against respiratory tract
IgG2. The HE and S glycoproteins were recognized earliest by the bovine im-
mune system while the N protein induced antibody responses during the later
stage of initial infection and the early stage of reinfection. The membrane (M)
glycoprotein was the least immunogenic of the major viral structural proteins.
Coronaviruses, a genus in the family Coronaviridae, are enveloped, positive-
strand RNA viruses that emerge as increasingly important causes of human and
animal diseases. These diseases include respiratory infections, gastroenteritis,