Could a nasal spray of engineered proteins be used as front-line prophylactic defense against the influenza infection and provide a new way to prevent infection of current and emerging influenza viruses? Recent evidence from a recently published study suggests that this novel approach to influenza prevention may indeed work, or at least in mice.
In the study, researchers engineered a multivalent biologic using carbohydrate-binding modules that bind with high affinity to sialic acid, the critical component of the cell surface receptor in the respiratory tract for the influenza virus. To test the efficacy of the novel biologic to prevent influenza, the researchers administered a single 1-ug intranasal dose to mice seven days prior to injecting the mice with a lethal challenge of the 2009 pandemic H1N1 influenza virus. The study found that the single dose provided complete protection from the virus.
Additionally, the study found that the novel biologic induced a significant cytokine response.
“These host cell responses protect against influenza infection and are less likely to become resistant than drugs aimed at the virus,” said Robert G. Webster, PhD, Rose Marie Thomas Chair, and member in the infectious diseases department of St. Jude Children’s Research Hospital, Memphis, Tenn., one of the investigators of the study.
According to Dr. Webster, the novel biologic acts in a different way from the neuroaminidase inhibitors to which the H1N1 viruses became totally resistant to in 2007 and 2008.
“This shows our vulnerability to emerging novel influenza viruses like the H7N9 virus that is currently causing up to 30% mortality in China,” he said.
While emphasizing that these results are encouraging, Dr. Webster cautioned that these studies are at the very early stages of development and that phase I studies in humans have not yet begun. He also emphasized that additional preclinical studies are needed for both circulating H1N1 influenza viruses as well as the H5N1 and H7N9 viruses.
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