Mucosal immunity, particularly IgA antibody, is the first line of defense in the upper respiratory tract. In addition, IgG and IgM are important in preventing viral pneumonia. Vaccination of the upper respiratory tract may induce production of these antibodies, therefore, lowering the risks for respiratory infection. Mice were immunized with whole Philippines (H3N2) influenza vaccine in combination with cholera toxin (CT) either intranasally (IN) or intraperitoneally (IP), followed by a subsequent IN challenge after 7 days. Fourteen days following primary immunization, serum antibody responses were measure-d by ELISA. Mice that received both primary and secondary IN immunizations produced the highest level of serum, nasal wash and fecal IgA. Serum IgG and IgM levels were high in both IN and IP immunized mice. To further assess antibody responses, anti-influenza antibody-forming cells within lungs, spleens, nasal passages, upper respiratory nodes and lower respiratory nodes were isolated 14 days following primary immunization. In concurrence with serum antibody production, IgA antibody forming cells in these tissues were highest in mice that had received two IN immunizations, while IgG and IgM antibody forming cells were similar between IN:IN and IP:IN immunized groups. In conclusion, we have determined the upper respiratory tract is a separate compartment of the immune system from that stimulated by systemic immunization.
|State||Published - 20 Mar 1998|