Replication characteristics of swine influenza viruses in precision-cut lung slices reflect the virulence properties of the viruses.
Precision-cut lung slices of pigs were infected with five swine influenza A viruses of different subtypes (A/sw/Potsdam/15/1981 H1N1, A/sw/Bad Griesbach/IDT5604/2006 H1N1, A/sw/Bakum/1832/2000 H1N2, A/sw/Damme/IDT5673/2006 H3N2, A/sw/Herford/IDT5932/2007 H3N2). The viruses were able to infect ciliated and mucus-producing cells. The infection of well-differentiated respiratory epithelial cells by swine influenza A viruses was analyzed with respect to the kinetics of virus release into the supernatant. The highest titres were determined for H3N2/2006 and H3N2/2007 viruses. H1N1/1981 and H1N2/2000 viruses replicated somewhat slower than the H3N2 viruses whereas a H1N1 strain from 2006 multiplied at significantly lower titres than the other strains. Regarding their ability to induce a ciliostatic effect, the two H3N2 strains were found to be most virulent. H1N1/1981 and H1N2/2000 were somewhat less virulent with respect to their effect on ciliary activity. The lowest ciliostatic effect was observed with H1N1/2006. In order to investigate whether this finding is associated with a corresponding virulence in the host, pigs were infected experimentally with H3N2/2006, H1N2/2000, H1N1/1981 and H1N1/2006 viruses. The H1N1/2006 virus was significantly less virulent than the other viruses in pigs which was in agreement with the results obtained by the in vitro-studies. These findings offer the possibility to develop an ex vivo-system that is able to assess virulence of swine influenza A viruses.
Fandan
F
Meng
Darsaniya
D
Punyadarsaniya
Sabine
S
Uhlenbruck
Isabel
I
Hennig-Pauka
Christel
C
Schwegmann-Wessels
Xiaofeng
X
Ren
Ralf
R
Dürrwald
Institute of Virology University of Veterinary Medicine, Hannover, Germany. Georg.Herrler@tiho-hannover.de.
Georg
G
Herrler
D000818:Animals; D004847:Epithelial Cells / Q000821:virology*; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D057221:Influenza A Virus, H1N2 Subtype / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D053122:Influenza A Virus, H3N2 Subtype / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D009980:Influenza A virus / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D008168:Lung / Q000821:virology*; D009976:Orthomyxoviridae Infections / Q000662:veterinary* / Q000821:virology; D013552:Swine; D013553:Swine Diseases / Q000821:virology*; D019562:Viral Load / Q000662:veterinary; D014774:Virulence; D014779:Virus Replication