Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA ; Department of Biochemistry, School of Pharmaceutical Sciences, University of Shizuoka, and Global COE Program for Innovation in Human Health Sciences, Japan.
FEBS Open Bio. 2012 Sep 5;2:261-6. doi: 10.1016/j.fob.2012.08.007. Print 2012.
Avian influenza A viruses (IAVs) and human 1918, 1957, and 1968 pandemic IAVs all have neuraminidases (NAs) that are stable at low pH sialidase activity, yet most human epidemic IAVs do not. We examined the pH stability of H5N1 highly pathogenic avian IAV (HPAI) NAs and identified amino acids responsible for conferring stability at low pH. We found that, unlike other avian viruses, most H5N1 IAVs isolated since 2003 had NAs that were unstable at low pH, similar to human epidemic IAVs. These H5N1 viruses are thus already human virus-like and, therefore, have the frequent infections of humans.
禽流感 A 病毒（IAV）和人类 1918、1957 和 1968 年大流行 IAV 都具有神经氨酸酶（NA），在低 pH 值下具有稳定的唾液酸酶活性，但大多数人类流行 IAV 则没有。我们研究了 H5N1 高致病性禽流感（HPAI）IAV 的 NA 在低 pH 值下的稳定性，并确定了赋予其在低 pH 值下稳定性的氨基酸。我们发现，与其他禽类病毒不同，自 2003 年以来分离到的大多数 H5N1 IAV 的 NA 在低 pH 值下不稳定，类似于人类流行 IAV。因此，这些 H5N1 病毒已经具有人类病毒样特征，因此经常感染人类。
