Immunity to influenza in ferrets. 3. Proteins in nasal secretions.

Abstract

Nasal washings from ferrets previously infected with influenza virus A2/Hong Kong/3/68 contain increased concentrations of total protein. The level of protein rose to a maximum, which was three- to fivefold greater than the normal concentration, at seven to nine days after infection, and subsequently fell to levels seen before infection by days 11-13 after infection. Nasal washings from ferrets that were immune to infection with influenza A2/Hong Kong/3/68 did not contain significantly increased levels of protein after challenge. Since an increase in protein in nasal washings was observed only in ferrets susceptible to infection with influenza virus, the measurement of nasal-wash protein was a good parameter for assessment of immunity to infection. A nasal-wash pool from normal ferrets contained only albumin and a trace amount of y-globulin. However, immunoelectrophoresis of a nasal-wash pool from infected animals showed five distinct proteins and trace amounts of two further proteins. Albumin was identified, together with an IgG, which was shown to be identical to serum IgG. However, no protein analogous to human secretory IgA or IgM was detected in the infected nasalwash pool.