3.3 In vitro inhibitory effects of aprotinin on
infections caused by oseltamivir-resistant influenza A and B viruses
We next examined the inhibitory effects of aprotinin against an
oseltamivir-resistant IAV (A/Bris/10/07; H3N2). As shown in Fig. 4A,
A/Bris/10/07 (H3N2) virus was less susceptible to oseltamivir. Our
genetic analysis revealed that the H28T mutation in HA conferred the
reduced susceptibility of the H3N2 virus to oseltamivir (data not
shown). However, aprotinin could effectively reduce the production of
the H3N2 virus (Fig. 5A).
IBVs are generally less susceptible to oseltamivir than IAVs.[21,22]
Therefore, we here investigated the inhibitory effects of aprotinin on
influenza B virus (B/Seoul/32/2011) infection. As shown in Fig. 5B, the
IBV was around 50- to 100-fold less susceptible to oseltamivir. However,
aprotinin was more effective than oseltamivir at reducing IBV
production.
Taken together, these results suggest that aprotinin can significantly
reduce the production of oseltamivir-resistant IAV and of IBV, which is
less susceptible to oseltamivir.