SUPPLEMENTATION OF CONVENTIONAL INFLUENZA-A VACCINE WITH PURIFIED VIRAL NEURAMINIDASE RESULTS IN A BALANCED AND BROADENED IMMUNE-RESPONSE

Influenza virus neuraminidase was chromatographically extracted from A /Johannesburg/33/94 (H3N2) and used to supplement conventional monoval ent H3(JH)N2(JH) inactivated influenza vaccine. Immunization of mice w ith this preparation resulted in high titers of antibodies to both hem agglutinin (HA) and neuraminidase (NA) equivalent for each antigen to titers in animals immunized with either antigen alone, Homotypic infec tion was suppressed and greater reduction in viral replication was obs erved following heterotypic infectious challenge than was observed fol lowing the non-supplemented vaccine. There was no evidence of suppress ion of the immune response to the HA despite the presence of high amou nts of NA in the vaccine, Supplementation of conventional inactivated influenza vaccine with NA takes advantage of the equivalent immunogeni city of dissociated HA and NA, to produce a more balanced immune respo nse to both surface antigens, without the antigenic competition tht oc curs after immunization with conventional vaccine or infection. These studies in a mouse model system suggest that supplementation of curren t inactivated influenza vaccines offers the prospect of improved immun ization of humans against influenza, (C) 1998 Elsevier Science Ltd, Al l rights reserved.