Immunoglobulin Classes of Serum Neutralizing Antibody Formed in Response to Immunization with Dead Influenza Virus Vaccine

Serum specimens obtained at weekly intervals from 4 normal adult volunteers immunized with dead influenza virus vaccine were fractionated on Sephadex G-200 in order to study the classes of immuno-globulins which make up the influenza virus neutralizing antibody. Neutralizing antibody activity was found only in the IgG class of immunoglobulins. This finding is similar to the results obtained in volunteers inoculated with live influenza virus via the respiratory tract. Since the neutralizing antibody in respiratory secretion is mostly found in the IgA class, the lack of IgA serum antibody supports the hypothesis of local production of antibody in external secretions.