H1N1/09 Influenza A Virus Infection of Immortalized First Trimester Human Trophoblast Cell Lines



Shihoko Komine-Aizawa, Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, 30-1 Ohyaguchikamicho, Itabashi-ku, Tokyo 173-8610, Japan.

E-mail: aizawa.shihoko@nihon-u.ac.jp



Although high maternal mortality was reported in the most recent pandemic of swine-origin influenza A H1N1/09 (H1N1/09), its direct effects on the feto-placental unit are unknown. In the present study, we examined the susceptibility of immortalized human trophoblasts to clinical isolates of pandemic 2009 H1N1 influenza A (H1N1/09) virus.

Method of study

The H1N1/09 virus was isolated from a patient with influenza, sequenced and identified as the A/Narita/2009 (H1N1) strain. The trophoblast cell lines Swan71 and HTR8 were challenged with the virus and examined for the expression of H1N1/09 viral RNA and proteins.


Viral RNA and proteins were observed 24 hr after inoculation. However, viral release was not detected.


First trimester human trophoblast cell lines were susceptible to the H1N1/09 influenza A virus. However, viral release and cytopathic effects were minimal. Our data suggest that placental damage by the H1N1/09 virus may be limited.