Neuraminidase- and Hemagglutinin-Inhibiting Antibodies in Serum and Nasal Secretions of Volunteers Immunized with Attenuated and Inactivated Influenza B/Eng/13/65 Virus Vaccines

Abstract

Abstract The antibody response to virus hemagglutinin and neuraminidase in serum and nasal secretions was studied in 19 volunteers immunized with attenuated or inactivated influenza B/Eng/13/65 virus vaccines. The live attenuated virus given intranasally produced high titers of neuraminidase- and hemagglutinin-inhibiting antibodies in nasal secretions and moderate titers in serum. High titers of hemagglutinin-inhibiting antibody were also present in nasal secretions and serum after subcutaneous immunization with inactivated influenza virus. However, the inactivated virus was found to produce little or no neuraminidase-inhibiting antibody in nasal secretion despite high titers of this antibody in the serum. Absorption studies indicated that the neuraminidase-inhibiting antibody in nasal secretion was associated with the IgA class of immunoglobin. These observations indicate that the intranasal administration of live virus was a better route for the stimulation of neuraminidase-inhibiting antibody in nasal secretion than a single subcutaneous dose of inactivated virus.