Comparative thermostability analysis of zoonotic and human influenza virus A and B neuraminidase

Abstract

Neuraminidase (NA) thermostability of influenza A and B viruses isolated from birds, swine and humans was measured to evaluate its variability associated with host body temperature. The highest 50% inactivation temperature (IT 50 ) was observed with H3N8 avian influenza virus (74 °C), and the lowest IT 50 was observed with the seasonal human H3N2 virus (45.5 °C).The IT 50 values of A(H1N1)pdm09 viruses 56.4-58.5 °C were statistically higher than that of the prepandemic strain A/ Solomon Islands/03/06 (52.5 °C). An analysis of Ca 2+ binding sites revealed the correspondence of amino acid changes to NA thermostability. This study demonstrates that changes in NA thermostability correspond to differences in host body temperature.

Host–Virus Interaction: How Host Cells Defend against Influenza A Virus Infection

“…In addition, NA possesses at least two calcium binding sites [21]. Gene analysis of these Ca 2+ binding sites reveals that they are related to NA thermostability, further suggesting a correlation between NA thermostability and virus adaption [22]. Furthermore, NA is also the major antigenic target of the host humoral immunity, and NA-specific antibodies function in limiting virus egress via interfering with the sialidase activity have drawn wide attention for development of antiviral therapies [23,24].…”