A pneumo-virulent United States isolate of porcine reproductive and respiratory syndrome virus induces apoptosis in bystander cells both in vitro and in vivo

• Published in: Journal of general virology Vol. 79; no. 12; pp. 2989 - 2995
• Main Authors: Sirinarumitr, T, Zhang, Y, Kluge, JP, Halbur, PG, Paul, PS
• Format: Journal Article
• Language: English
• Published: England Soc General Microbiol 01-12-1998
• Subjects: Animals; Apoptosis; Porcine Reproductive and Respiratory Syndrome - pathology; Porcine Reproductive and Respiratory Syndrome - virology; Porcine respiratory and reproductive syndrome virus; Porcine respiratory and reproductive syndrome virus - physiology; Swine; United States; Virulence; United States
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/0022-1317-79-12-2989

T Sirinarumitr, Y Zhang, JP Kluge, PG Halbur and PS Paul
Department of Veterinary Pathology, Veterinary Medical Research Institute, College of Veterinary Medicine, Iowa State University, Ames 50011, USA.
Evidence of apoptosis was detected for the United States porcine
reproductive and respiratory syndrome virus (PRRSV) in ATCC CRL11171 cells
inoculated with strain ATCC VR2385 and in the tissues of pigs infected with
the same strain. Apoptosis was detected by agarose gel electrophoresis,
transmission electron microscopy and terminal deoxytransferase dUTP nick
end labelling (TUNEL) techniques. By electron microscopy and
double-labelling techniques, apoptosis was detected primarily in uninfected
bystander cells in the continuous cell line rather than the PRRSV-infected
cells. In the lungs, the apoptotic cells were predominantly alveolar and
pulmonary intravascular macrophages, and mononuclear cells in the alveolar
septa. In the lymph nodes, the apoptotic cells were predominantly tingible
body macrophages and mononuclear cells. The induction of apoptosis in a
large number of mononuclear cells in the lungs and lymph nodes appears to
be a mechanism of PRRSV pathogenesis and might be an explanation for a
dramatic reduction in the number of alveolar macrophages and circulating
lymphocytes and monocytes in PRRSV-infected pigs.