MDCK SIAT-1 cells show improved isolation rates for recent human influenza viruses compared to conventional MDCK cells

WHO Collaborating Centre for Reference and Research on Influenza, 45 Poplar Road, Parkville, Melbourne, Australia, 3052; School of Applied Sciences and Engineering, Monash University Gippsland Campus, Churchill, Victoria, Australia, 3842

^* To whom correspondence should be addressed. Email: karen.laurie{at}influenzacentre.org.

	Abstract

The ability to isolate and propagate influenza virus is an essential tool for yearly surveillance of circulating virus strains, and to ensure an accurate clinical diagnosis for appropriate treatment. The suitability of MDCK-SIAT1 cells, engineered to express increased levels of -2,6-linked sialic acid receptors, as an alternative to conventional MDCK cells for isolation of circulating influenza virus was assessed. A higher number of influenza A (H1N1 and H3N2) and B viruses from stored human clinical specimens collected between 2005 and 2007 was isolated following inoculation in MDCK-SIAT1 cells compared to MDCK cells. In addition, a higher titre of virus was recovered following culture in MDCK-SIAT1 cells. All A(H1N1) viruses recovered from MDCK-SIAT1 cells were able to agglutinate both turkey and guinea pig RBC, whilst half of the A(H3N2) viruses recovered after passage in MDCK-SIAT1 cells lost the ability to agglutinate turkey RBC. Importantly, the HA-1 domain of the haemagglutinin gene was genetically stable after passaging in MDCK-SIAT1 cells, a feature not always seen following MDCK cell- or embryonated chicken egg-passage of human influenza virus. These data indicate that the MDCK-SIAT1 cell line is superior to conventional MDCK cells for isolation of human influenza from clinical specimens and may be used routinely for the isolation and propagation of current human influenza viruses, for surveillance, diagnostic and research purposes.