Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 20, 2002
Publication Date: July 20, 2002
Technical Abstract: Our previous studies have shown that mice immunized with recombinant adenovirus encoding the hemagglutinin gene (rAd-HA) of swine influenza H3N2 virus were protected from lethal challenge with heterologous virus, A/HK/1/68 (H3N2). Here, we extend these studies to evaluate the protective mechanism induced by rAd-HA. Balb/c mice were immunized twice with rAd-HA. Four weeks after the 2nd immunization, both immunized and control mice wer challenged with 10 LD50 of A/HK/1/68 (H3N2). Five mice from each group were killed at 0, 5, 10, 15 and 20 days post challenge. Lymphocytes were isolated from mediastinal lymph node, lung and spleen and the cells were stimulated with K**d-restricted HA peptide (IYSTVASSL) at 37 C in a humidified atmosphere containing 6% CO2. After 6 hours incubation, cells were labeled with monoclonal antibodies for lymphocyte surface markers (CD4, CD8) and intracellular cytokines [interferon gamma (-IFN) and IL-4]. FASC analysis showed that 40% of lymphocytes isolated from lungs of mice immunized with rAd-HA and killed 10 days post challenge secreted -IFN and were negative for both CD4 and CD8. No cells secreted IL-4 and cells from control mice were negative for interferon gamma. Additional studies are in progress to examine the role of these cells in protection from heterologous virus. Evaluation of the specific immune response induced by recombinant adenoviral vaccine will improve the understanding of protective immunity against swine influenza and lead to the development of more efficacious swine vaccines.