The proteins in nasal secretion. II. A longitudinal study of IgA and neutralizing antibody levels in nasal washings from men infected with influenza virus

Following influenza virus infection, virus-neutralizing antibody was detected earlier, rose to high titers sooner, and was demonstrable more frequently in nasal washings from men who had had relatively high concentrations of immunoglobulin A (IgA) in their nasal washings prior to the infection. Four men who had relatively low levels of nasal IgA before inoculation were the only ones who experienced typical febrile influenza. Virus-neutralizing antibody was detected relatively late and infrequently in the postinoculation nasal washings from these men. These findings suggest that the immunologic response to influenza virus at the mucous membrane surface may play a role in limiting infection, and thereby avert clinical illness.