Deletions in the neuraminidase stalk region of H2N2 and H9N2 avian influenza subtypes do not affect post-influenza secondary bacterial pneumonia.

CHOCKALINGAM AK; HICKMAN D; PENA L; YE J; FERRERO A; ECHENIQUE JR; CHEN H; SUTTON T; PEREZ DR.

AMER SOC MICROBIOLOGY

Año: 2012 vol. 86 p. 3564 - 3564

e investigated the synergism between influenza and Streptococcus pneumoniae (Sp), particularly the role of deletions in the stalk region of the neuraminidase (NA) of H2N2 and H9N2 avian influenza viruses. Deletions in the NA stalk (ΔNA) had no effect on NA activity or in adherence of Sp on virus-infected human alveolar epithelial (A549) and mouse lung adenoma (LA-4) cells, although it delayed virus elution from turkey red blood cells. Sequential Sp infection of mice previously inoculated with isogenic recombinant influenza H2N2 and H9N2 viruses displayed severe pneumonia, elevated levels of intrapulmonary pro-inflammatory responses and death. No differences between wt and ΔNA viruses were detected with respect to effects in post-influenza pneumococcal pneumonia as measured by bacterial growth, lung inflammation, morbidity, mortality, and cytokine/chemokine concentrations. Differences were observed, however, in influenza-infected mice that were treated with oseltamivir prior